Joining dissimilar materials encounters significant engineering challenges due to the contrast in material properties that makes conventional welding not feasible.Magnetic Pulse Welding(MPW)offers a solidstate joining...Joining dissimilar materials encounters significant engineering challenges due to the contrast in material properties that makes conventional welding not feasible.Magnetic Pulse Welding(MPW)offers a solidstate joining technique that overcomes these issues by using impact to create strong bonds without melting the substrate materials.This study investigates the weldability of aluminum alloy Al-5754 with Al-7075 and MARS 380 steel,used in armouring solutions of defense systems,by the use of MPW.In this work,weldability windows are investigated by varying standoff distances between the coating material and its substrate(0.25-4.5 mm)and discharge energies(5-13 kJ)with both O-shape and U-shape inductors.Mechanical strength of the welded joints were assessed through single lap shear tests,identifying optimal welding parameters.Then,the velocity profiles of the flyer plates were measured using heterodyne velocimetry to understand the dynamics of the impact.Then,substructures assembled with the optimal welding conditions were subjected to ballistic testing using 7.62 mm×51 mm NATO and 9 mm×19 mm Parabellum munitions to evaluate the resilience of the welds under ballistic impact.The outcomes demonstrate that MPW effectively joins Al-5754 with both Al-7075 and MARS 380,producing robust welds capable of withstanding ballistic impacts under certain conditions.This research advances the application of MPW in lightweight ballistic protection of defense systems,contributing to the development of more resilient and lighter protective structures.展开更多
Physical and chemical processes observed in the mesosphere and thermosphere above the Earth’s low latitudes are complex and highly interrelated to activity in the low-latitude ionosphere.Metallic sodium detected by l...Physical and chemical processes observed in the mesosphere and thermosphere above the Earth’s low latitudes are complex and highly interrelated to activity in the low-latitude ionosphere.Metallic sodium detected by lidar can yield clues to dynamic and chemical processes in these spatial layers above the Earth’s atmosphere.This paper is based on sodium layer data collected at two low-latitude stations,one in the northern hemisphere and one in the southern.The low-latitude sodium layer exhibits conspicuous seasonal variations in shape,density,and altitude;these variations are similar between Earth’s hemispheres:sodium layer density at both stations reaches its seasonal maximum in autumn and minimum in summer.However,maximal Na density over Brazil is greater than that over Hainan.Nocturnal variations of Na density above the two low-latitude stations are also similar;at both,maxima are observed before sunrise.Some variations of the Na layer over Brazil that differ from those observed in the northern hemisphere may be related to the South Atlantic Magnetic Anomaly(SAMA)or fountain effect.We suggest that low-latitude Na layer data may provide useful additional evidence that could significantly improve the low-latitude part of the WACCM-Na model.展开更多
Colloidal transport and deposition in porous media are complex processes that result from the interaction between hydrodynamics(velocity,pore geometry,etc.)and Derjaguin-Landau-Verwey-Overbeek(DLVO)forces(particle-par...Colloidal transport and deposition in porous media are complex processes that result from the interaction between hydrodynamics(velocity,pore geometry,etc.)and Derjaguin-Landau-Verwey-Overbeek(DLVO)forces(particle-particle and particle-surface).They have important implications for engineering applications involving the reinjection of a fluidinto a medium,such as geothermal energy.The investigation of permeability stability is critical to ensure the sustainability of activities.This work aims to study the clogging mechanisms in a rock-like porous medium using a microfluidicdevice.The pore-throat network distributions reveal that the micromodel geometry mimics real rock samples.The transport of a monodispersed suspension is studied at different concentrations.Image analysis,velocity fieldmodeling,and pressure drop measurement are used to assess preferential clogging sites and porous medium permeability reduction,respectively.Experiments have shown that retention sites are located around preferential flow paths with relatively high flow velocities.When clogged,the pore thresholds are the deposition zones that lead to a reduction in permeability.However,pore bodies may also constitute deposition zones.Interestingly,as the concentration of the suspension increases,the kinetics of the permeability reduction are delayed,and the clogging mechanisms,as well as the type of deposit,evolve.Finally,at very high concentrations,the effects of hydrodynamic stripping are more important.These observations emphasize the role of the porous medium geometry in colloidal transport and deposition and thus permeability reduction.展开更多
The mechanical properties of solid oxide fuel cells(SOFCs)can limit their mechanical stability and lifespan.Understanding the correlation between the microstructure and mechanical properties of porous electrode is ess...The mechanical properties of solid oxide fuel cells(SOFCs)can limit their mechanical stability and lifespan.Understanding the correlation between the microstructure and mechanical properties of porous electrode is essential for enhancing the performance and durability of SOFCs.Accurate prediction of mechanical properties of porous electrode can be achieved by microscale finite element modeling based on three-dimensional(3D)microstructures,which requires expensive 3D tomography techniques and massive computational resources.In this study,we proposed a cost-effective alternative approach to access the mechanical properties of porous electrodes,with the elastic properties of La_(0.6)Sr_(0.4)Co_(0.2)Fe_(0.8)O_(3-δc)athode serving as a case study.Firstly,a stochastic modeling was used to reconstruct 3D microstructures from two-dimensional(2D)cross-sections as an alternative to expensive tomography.Then,the discrete element method(DEM)was used to predict the elastic properties of porous ceramics based on the discretized 3D microstructures reconstructed by stochastic modeling.Based on 2D microstructure and the elastic properties calculated by the DEM modeling of the 3D reconstructed porous microstructures,a convolutional neural network(CNN)based deep learning model was built to predict the elastic properties rapidly from 2D microstructures.The proposed combined framework can be implemented with limited computational resources and provide a basis for rapid prediction of mechanical properties and parameter estimation for multiscale modeling of SOFCs.展开更多
Pollution from road traffic contributes significantly to air pollution through pollutants from exhaust emissions(gases and particles)and non-exhaust emissions(tire wear particles,brake wear particles and the resuspens...Pollution from road traffic contributes significantly to air pollution through pollutants from exhaust emissions(gases and particles)and non-exhaust emissions(tire wear particles,brake wear particles and the resuspension of road dust).This research examined the hazard of tire particles(TP)and in particular evaluated the effect of TP size on lung macrophages.TP were obtained by cryogenic grinding of a tire and subsequent sieving to obtain four groups of particles(TP70,TP30,TP15,TP5)of different sizes with average diameters of 107μm,55μm,22μm,and 6μm,respectively.A complete physicochemical characterization was performed to determine the size distribution,chemical composition and morphology of these particles.We then investigated the proinflammatory response,oxidative stress and cytotoxicity induced in RAW264.7 cells exposed to four different TP concentrations for 24 h.TP had no direct effect on cytotoxicity,nor did they increase reactive oxygen species(ROS)production in the cells.However,TP induced a significant and size-dependent proinflammatory effect,which was particularly pronounced with small particles.Moreover,this effect was concentration-dependent.展开更多
Objectives:Cisplatin(CDDP)therapy for glioblastoma(GBM)is linked with several limitations,which include poor penetration of the blood-brain barrier(BBB),systemic toxicity,and the development of drug resistance mechani...Objectives:Cisplatin(CDDP)therapy for glioblastoma(GBM)is linked with several limitations,which include poor penetration of the blood-brain barrier(BBB),systemic toxicity,and the development of drug resistance mechanisms implicating oxidative stress dysregulation and compromised apoptotic pathways.This study evaluates C-Phycocyanin(C-PC)as a potential adjuvant to enhance CDDP efficacy by modulating redox balance and apoptosis.Methods:GBM cells(U87 and U87-EGFRvIII)were treated with CDDP,C-PC,or their combination.Cell viability was assessed by MTT assay;apoptosis was evaluated by DAPI staining andWestern blot analysis of cleaved Caspase-3 and poly(ADP-ribose)polymerase(PARP).Both intracellular and extracellular reactive oxygen species(ROS)were measured using 2′,7′-dichlorodihydrofluorescein diacetate(DCF-DA)fluorescence and lucigenin chemiluminescence,respectively.Catalase activity was quantified via hydrogen peroxide(H2O2)decomposition assay,and manganese superoxide dismutase(MnSOD)expression byWestern blot.Results:C-PCselectively decreased U87GBMcell viability while sparing normal cells.C-PC enhanced CDDP cytotoxicity,reducing viability to 26.5%vs.53.2%for CDDP alone.This effect correlated with increased apoptosis,evidenced by DNA fragmentation and higher cleaved caspase-3 and PARP levels.Combined treatment lowered ROS below survival thresholds while upregulating MnSOD and catalase activity.In U87-EGFRvIII cells,CDDP reduced viability modestly(85.2%),C-PC alone decreased viability significantly(51.5%)and induced cell death,but the combination did not further increase apoptosis.Here,C-PC’s pro-apoptotic effects,alone or with CDDP,were also associated with reduced oxidative stress in cells.Conclusion:We demonstrate that C-PC enhances CDDP cytotoxicity in sensitive U87 cells by promoting apoptosis and modulating ROS,suggesting potential for improved therapeutic efficacy with reduced systemic toxicity.Compared to the combination,C-PC monotherapy achieves superior cytotoxicity in CDDP-resistant U87-EGFRvIII cells,underscoring its potential as a standalone therapeutic approach for chemotherapy-resistant glioblastoma subtypes.展开更多
This study investigates the role of Interleukin 17(IL-17)in exacerbating periapical lesions caused by Porphyromonas gingivalis(Pg)lipopolysaccharides(LPS)in the context of metabolic disease and its potential impact on...This study investigates the role of Interleukin 17(IL-17)in exacerbating periapical lesions caused by Porphyromonas gingivalis(Pg)lipopolysaccharides(LPS)in the context of metabolic disease and its potential impact on glucose tolerance.Researchers developed a unique mouse model where mice were monocolonized with Pg to induce periapical lesions.After 1 month,they were fed a highfat diet(HFD)for 2 months to simulate metabolic disease and oral microbiota dysbiosis.To explore the role of LPS from Pg,wildtype(WT)mice were challenged with purified LPS from Porphyromonas gingivalis,as well as with LPS-depleted and non-depleted Pg bacteria;IL-17 knockout(KO)mice were also included to assess the role of IL-17 signaling.The impact on bone lysis,periapical injury,glucose intolerance,and immune response was assessed.Results showed that in WT mice,the presence of LPS significantly worsened bone lysis,Th17 cell recruitment,and periapical injury.IL-17 KO mice exhibited reduced bone loss,glucose intolerance,and immune cell infiltration.Additionally,inflammatory markers in adipose tissue were lower in IL-17 KO mice,despite increased dysbiosis.The findings suggest that IL-17 plays a critical role in amplifying Pg-induced periapical lesions and systemic metabolic disturbances.Targeting IL-17 recruitment could offer a novel approach to improving glycemic control and reducing type 2 diabetes(T2D)risk in individuals with periapical disease.展开更多
The chemical and electrochemical stability of lanthanide nickelates La2 NiO4+δ(LNO),Pr2 NiO4+δ(PNO)and their mixed compounds La(2-x)PrxNiO4+δ(LPNOs)with x=0.5,1 or 1.5 is reported.The aim is to promote these materi...The chemical and electrochemical stability of lanthanide nickelates La2 NiO4+δ(LNO),Pr2 NiO4+δ(PNO)and their mixed compounds La(2-x)PrxNiO4+δ(LPNOs)with x=0.5,1 or 1.5 is reported.The aim is to promote these materials as efficient electrodes for solid oxide fuel cell(SOFC)and/or solid oxide electrolysis cell(SOEC).La2 NiO4+δand La1.5Pr0.5NiO4+δcompounds are chemically very stable as powders over one month in the temperature range 600-800℃,while the other materials rich in praseodymium progressively decompose into various perovskite-deriving components with additional Pr6 O11.Despite their uneven properties,all these materials are quite efficient and sustainable as electrodes on top of gadolinium doped ceria(GDCBL)//yttrium doped zirconia(8 YSZ)electrolyte,for one month at 700℃without polarization.Under polarization(300 mA·cm-2),the electrochemical performances of LNO,PNO and La1.5Pr0.5NiO4+δ(LP5 NO)quickly degrade in SOFC mode,i.e.for the oxygen reduction reaction,while they show durability in SOEC mode,i.e.for the oxide oxidation reaction.展开更多
The introduction of tacrolimus in clinical practice has improved patient survival after organ transplant.However,despite the long use of tacrolimus in clinical practice,the best way to use this agent is still a matter...The introduction of tacrolimus in clinical practice has improved patient survival after organ transplant.However,despite the long use of tacrolimus in clinical practice,the best way to use this agent is still a matter of intense debate.The start of the genomic era has generated new research areas,such as pharmacogenetics,which studies the variability of drug response in relation to the genetic factors involved in the processes responsible for the pharmacokinetics and/or the action mechanism of a drug in the body.This variability seems to be correlated with the presence of genetic polymorphisms.Genotyping is an attractive option especially for the initiation of the dosing of tacrolimus;also,unlike phenotypic tests,the genotype is a stable characteristic that needs to be determined only once for any given gene.However,prospective clinical studies must show that genotype determination before transplantation allows for better use of a given drug and improves the safety and clinical efficacy of that medication.At present,research has been able to reliably show that the CYP3A5 genotype,but not the CYP3A4 or ABCB1 ones,can modify the pharmacokinetics of tacrolimus.However,it has not been possible to incontrovertibly show that the corresponding changes in the pharmacokinetic profile are linked with different patient outcomes regarding tacrolimus efficacy and toxicity.For these reasons,pharmacogenetics and individualized medicine remain a fascinating area for further study and may ultimately become the face of future medical practice and drug dosing.展开更多
The vanadium redox flow battery(VRFB)has been receiving great attention in recent years as one of the most viable energy storage technologies for large-scale applications.However,higher concentrations of vanadium spec...The vanadium redox flow battery(VRFB)has been receiving great attention in recent years as one of the most viable energy storage technologies for large-scale applications.However,higher concentrations of vanadium species are required in the H_(2)O-H_(2)SO_(4) electrolyte in order to improve the VRFB energy density.This might lead to unwanted precipitation of vanadium compounds,whose nature has not been accurately characterized yet.For this purpose,this study reports the preparation ofⅤ^((Ⅱ)),ⅤV^((Ⅲ)),Ⅴ^((Ⅳ))andⅤ^((Ⅴ))supersaturated solutions in a 5 M H_(2)SO_(4)-H_(2)O electrolyte by an electrolytic method,from the only vanadium sulfate compound commercially available(VOSO_(4)).The precipitates obtained by ageing of the stirred solutions are representative of the solids that may form in a VRFB operated with such supersaturated solutions.The solid phases are identified using thermogravimetric analysis,X-ray diffraction and SEM.We report that dissolvedⅤ^((Ⅱ)),Ⅴ^((Ⅲ))andⅤ^((Ⅳ))species precipitate as crystals of VSO_(4),V_(2)(SO_(4))3 and VOSO_(4) hydrates and not in their anhydrous form;conversely V^((Ⅴ))precipitates as an amorphous V_(2) O_(5) oxide partially hydrated.The measured hydration degrees(respectively 1.5,9,3 and 0.26 mol of H_(2)O per mol of compound)might significantly affect the overall engineering of VRFB operating with high vanadium concentrations.展开更多
A volume averaged columnar solidification model,which couples the flow,temperature and solute concentration fields,is applied to simulate experimental continuous casting cases with and without vertical electromagnetic...A volume averaged columnar solidification model,which couples the flow,temperature and solute concentration fields,is applied to simulate experimental continuous casting cases with and without vertical electromagnetic stirring(V-EMS).The calculated distribution of magnetic induction intensity and final macrosegregation maps are consistent with the experimental results.Calculation results reveal that the V-EMS promotes longitudinal melt flow,accelerates heat dissipation and solidification and finally reduces the central segregation of carbon.However,when V-EMS is applied,the solute distribution becomes asymmetric because the melt flow shows opposite directions between the near and far sides from stirrer.An obvious positive segregation band is observed at about 1/4 width of the billet near the stirrer in both calculated and experimental results.The position and degree of such positive segregation could be affected by installation height of stirrer,as demonstrated by additional simulation cases.展开更多
Projections of climate change are essential to guide sustainable development plans in the tropical Andean countries such as Peru. This study assessed the projections of precipitation and potential evaporation, rain er...Projections of climate change are essential to guide sustainable development plans in the tropical Andean countries such as Peru. This study assessed the projections of precipitation and potential evaporation, rain erosive potential, and precipitation concentration in the Mantaro River Basin, in the Peruvian Andes, which is important for agriculture and energy production in Peru. We assumed the Intergovernmental Panel on Climate Change （IPCC） AIB greenhouse gas emission scenario and simulated the global climate change by the HadCM3 global climate model. Due to the steepness of the mountain slopes and the narrowness of the river valley, this study uses the downscaling of the global model simulations by the regional Eta model down to 2o-km resolution. The downscaling projections show decrease in the monthly precipitation with respect to the baseline period, especially during the rainy season, between February and April, until the end of the 21st century. Meanwhile, a progressive increase in the monthly evaporation from the baseline period is projected. The Modified Fournier Index （MFI） shows a statistically significant downward trend in the Mantaro River Basin, whieh suggests a possible reduction in the rain erosive potential. The Precipitation Concentration Index （PCI） shows a statistically significant increasing trend, which indicates increasingly more irregular temporal distribution of precipitation towards the end of the century. The results of this study allow us to conclude that there should be a gradual increase in water deficit and precipitation concentration. Both changes can be negative for agriculture, power generation, and water supply in the Mantaro River Basin in Peru.展开更多
The present study focuses on the impacts of extreme drought and flooding situations in Amazonia, using level/discharge data from some rivers in the Amazon region as indicators of impacts. The last 10 years have featur...The present study focuses on the impacts of extreme drought and flooding situations in Amazonia, using level/discharge data from some rivers in the Amazon region as indicators of impacts. The last 10 years have featured various “once in a century” droughts and floods in the Amazon basin, which have affected human and natural systems in the region. We assess a history of such hazards based on river data, and discuss some of the observed impacts in terms of vulnerability of human and natural systems, as well as some of adaptation strategies implemented by regional and local governments to cope with them. A critical perspective of mitigation of drought and flood policies in Amazonia suggests that they have been mostly ineffective in reducing vulnerability for the majority of the population, constituting, perhaps, examples of maladaptation via the undermining of resilience.展开更多
This paper proposes an estimate of the stirring intensity needed to maintain an efficient segregation of impurities towards the liquid when crystallizing semiconductors such as silicon,with rapid solidification rates(...This paper proposes an estimate of the stirring intensity needed to maintain an efficient segregation of impurities towards the liquid when crystallizing semiconductors such as silicon,with rapid solidification rates(several cm/h).The method,valid far from stagnation points or detachments,is based on the properties of turbulent boundary layers,with a normal velocity of the liquid towards the solid/liquid interface due to solidification,that has the same effect as boundary layer suction in aeronautics.The transition between the diffusive regime(no segregation),and the convective regime(efficient segregation)occurs if the friction at the wall is greater than a threshold depending on the solidification rate.A chart is given to estimate the convecto-diffusive parameter from the ratio between stirring and solidification velocity,and the Reynolds number.展开更多
A deep understanding of the physical processes coming along with the current interruption in high voltage circuit breakers is essential for the optimization of today’s switching technologies.Therefore a switching arc...A deep understanding of the physical processes coming along with the current interruption in high voltage circuit breakers is essential for the optimization of today’s switching technologies.Therefore a switching arc in a model circuit breaker is studied by means of computational fluid dynamics(CFD)simulations and optical emission spectroscopy(OES)in this contribution.Experimental investigations are performed in carbon dioxide(CO2)at absolute filling pressures of 0.1 and 0.5 MPa.CFD simulations are carried out based on a model of the arcing zone including a consistent treatment of the radiation transport and the wall ablation.Carbon ion line radiation is analysed in the experiment using an optical path in the heating channel between the electrodes inside the nozzle system.The pressure value in the arc is estimated based on the line width-intensity dependence.Obtained values correspond to the measured pressure outside the arc.For the temperature profiles,a good agreement within the accuracy of the approaches is observed between the CFD simulations and the results of OES.展开更多
The solution-treated Mg-4Y-4Sm-0.5Zr alloy was extruded at temperatures from 325℃ to 500℃.Dynamic recrystallization(DRX) completely occurs when the alloy is extruded at 350℃and above.The grains of the extruded allo...The solution-treated Mg-4Y-4Sm-0.5Zr alloy was extruded at temperatures from 325℃ to 500℃.Dynamic recrystallization(DRX) completely occurs when the alloy is extruded at 350℃and above.The grains of the extruded alloy are obviously refined by the occurrence of DRX.The average grain size of the extruded alloy increases with increasing the extrusion temperature,leading to a slight decrease of the ultimate tensile strength(UTS) and the yield strength(YS) .On the contrary,the UTS and YS of the extruded and aged alloy increase with increasing the extrusion temperature.Values of UTS of 400 MPa,YS larger than 300 MPa and elongation(EL) of 7%are achieved after extrusion at 400℃ and ageing at 200℃ for 16 h.Both grain refinement and precipitation are efficient strengthening mechanisms for the Mg-4Y-4Sm-0.5Zr alloy.展开更多
In the restricted three-body problem,the traditional Lagrange points L1 and L2 are the only equilibrium points near the asteroid 243 Ida.The thrust generated by a solar sail over a spacecraft enables the existence of ...In the restricted three-body problem,the traditional Lagrange points L1 and L2 are the only equilibrium points near the asteroid 243 Ida.The thrust generated by a solar sail over a spacecraft enables the existence of new artificial equilibrium points,which depend on the position of the spacecraft with respect to the asteroid and the attitude of the solar sail.Such equilibrium points generate new spots to observe the body from above or below the plane of motion.Such points are very good observational locations due to their stationary condition.This work provides a preliminary analysis to observe Ida through the use of artificial equilibrium points as spots combined with transfer maneuvers between them.Such combination can be used to observe the asteroid from more different points of view in comparison to fixed ones.The analyses are made for a spacecraft equipped with a solar sail and capable of performing bi-impulsive maneuvers.The solar radiation pressure is used both to maintain the equilibrium condition and to reduce the costs of the transfers and/or to create transfers with longer duration.This is a new aspect of the present research,because it combines the continuous thrust with initial and final small impulses,which are feasible for most of the spacecraft,because the magnitudes of the impulses are very low.These combined maneuvers may reduce the transfer times of the maneuvers in most of the cases,compared with the maneuvers based only on continuous thrust.Several options involved in these transfers are shown,like to minimize the fuel spent(Dv)as a function of the transfer time or to extend the duration of the travel between the points.Extended transfer times can be useful when observations are required during the transfers.展开更多
Cellulose is the most abundant biomass material in nature and it is mainly extracted from natural or lignocellulosic fibers.After purification,cellulose fibers exhibit two interesting features for their further transf...Cellulose is the most abundant biomass material in nature and it is mainly extracted from natural or lignocellulosic fibers.After purification,cellulose fibers exhibit two interesting features for their further transformation into nanomaterials:a hierarchical and multi-level strcture,and a semicrystalline microstructure.Different forms of cellulose nanomaterials,resulting from a top-down deconstructing strategy(cellulose nanocrystals(CNCs),cellulose nanofibrils(CNFs))or bottom-up strategy(bacterial cellulose(BC))can be prepared.Multiple mechanical shearing actions applied to cellulosic fibers release more or less the nanofibrils individually.A controlled strong acid hydrolysis treatment can be applied to cellulosic fibers allowing dissolution of non-crystalline domains.Such cellulose nanomaterials have been the focus of an exponentially increasing number of works or reviews devoted to understand such materials and their applications.They have a high potential for an emerging industry.In the nanoscale,cellulose exhibits specific properties broadening the applications of this naturally occurring polymer.An overview of existing methods for the preparation of cellulose nanomaterials and their specific properties that outperform and contrast with cellulose in the microscale is proposed.展开更多
In the context of the Cigeo project,the French National Radioactive Waste Management Agency(Andra)is studying the behaviour of a deep geological facility for radioactive waste deposit in the CallovoOxfordian(COx)clays...In the context of the Cigeo project,the French National Radioactive Waste Management Agency(Andra)is studying the behaviour of a deep geological facility for radioactive waste deposit in the CallovoOxfordian(COx)claystone.The assessment of durability of this project requires the prediction of irreversible strain over a large time scale.The mechanical interaction of the host rock and the concrete support of tunnels must be investigated to ensure the long-term sustainability of the structure.The instantaneous and time-dependent behaviour of the claystone-concrete interface is experimentally investigated with direct shear tests and long-duration shear tests of a few months.The mechanical and structural state of the claystone which is affected after interaction with concrete reflects to the response of the claystone-concrete interface,and thus different types of COx claystone-concrete interfaces are tested.The delayed deformation of the interface is found to be linked to the level of the normal loading and the loading history while a different response of the interface was observed from the short-and long-duration tests,indicating a possible progressive modification of interface under long-duration loadings.展开更多
Double-pulse LIBS is a promising technique for deep-sea applications.LIBS measurements in shallow water with up to 400 mJ each pulse were done to select laser parameters which promote optimized spectral line emission ...Double-pulse LIBS is a promising technique for deep-sea applications.LIBS measurements in shallow water with up to 400 mJ each pulse were done to select laser parameters which promote optimized spectral line emission from plasma even at elevated pressures,where line broadening until loss of most of the spectral information can occur.Optical emission spectroscopy,using a Czerny-Turner spectrometer,has been applied to investigate the dependence of the emitted radiation on laser parameters and hydrostatic pressure.It has been found,that higher laser pulse energies,especially with short pulse delay as required in high water pressure,can also have an adverse effect on the measured spectrum.展开更多
基金funded on the one hand by Agence de l'Innovation de Défense(AID)grant reference number 2021650044on the other hand by Ecole Centrale de Nantes。
文摘Joining dissimilar materials encounters significant engineering challenges due to the contrast in material properties that makes conventional welding not feasible.Magnetic Pulse Welding(MPW)offers a solidstate joining technique that overcomes these issues by using impact to create strong bonds without melting the substrate materials.This study investigates the weldability of aluminum alloy Al-5754 with Al-7075 and MARS 380 steel,used in armouring solutions of defense systems,by the use of MPW.In this work,weldability windows are investigated by varying standoff distances between the coating material and its substrate(0.25-4.5 mm)and discharge energies(5-13 kJ)with both O-shape and U-shape inductors.Mechanical strength of the welded joints were assessed through single lap shear tests,identifying optimal welding parameters.Then,the velocity profiles of the flyer plates were measured using heterodyne velocimetry to understand the dynamics of the impact.Then,substructures assembled with the optimal welding conditions were subjected to ballistic testing using 7.62 mm×51 mm NATO and 9 mm×19 mm Parabellum munitions to evaluate the resilience of the welds under ballistic impact.The outcomes demonstrate that MPW effectively joins Al-5754 with both Al-7075 and MARS 380,producing robust welds capable of withstanding ballistic impacts under certain conditions.This research advances the application of MPW in lightweight ballistic protection of defense systems,contributing to the development of more resilient and lighter protective structures.
基金supported by the NSFC (42374204, 42004143,42364012)the Project of Stable Support for Youth Team in Basic Research Field,Chinese Academy of Sciences (Grant No.YSBR-018)+3 种基金the Scientific Projects of Hainan Province(KJRC2023C05, ZDYF2021GXJS040)the Innovational Fund for Scientific and Technological Personnel of Hainan Provincethe Chinese Meridian ProjectPandeng Program of National Space Science Center,Chinese Academy of Sciences
文摘Physical and chemical processes observed in the mesosphere and thermosphere above the Earth’s low latitudes are complex and highly interrelated to activity in the low-latitude ionosphere.Metallic sodium detected by lidar can yield clues to dynamic and chemical processes in these spatial layers above the Earth’s atmosphere.This paper is based on sodium layer data collected at two low-latitude stations,one in the northern hemisphere and one in the southern.The low-latitude sodium layer exhibits conspicuous seasonal variations in shape,density,and altitude;these variations are similar between Earth’s hemispheres:sodium layer density at both stations reaches its seasonal maximum in autumn and minimum in summer.However,maximal Na density over Brazil is greater than that over Hainan.Nocturnal variations of Na density above the two low-latitude stations are also similar;at both,maxima are observed before sunrise.Some variations of the Na layer over Brazil that differ from those observed in the northern hemisphere may be related to the South Atlantic Magnetic Anomaly(SAMA)or fountain effect.We suggest that low-latitude Na layer data may provide useful additional evidence that could significantly improve the low-latitude part of the WACCM-Na model.
文摘Colloidal transport and deposition in porous media are complex processes that result from the interaction between hydrodynamics(velocity,pore geometry,etc.)and Derjaguin-Landau-Verwey-Overbeek(DLVO)forces(particle-particle and particle-surface).They have important implications for engineering applications involving the reinjection of a fluidinto a medium,such as geothermal energy.The investigation of permeability stability is critical to ensure the sustainability of activities.This work aims to study the clogging mechanisms in a rock-like porous medium using a microfluidicdevice.The pore-throat network distributions reveal that the micromodel geometry mimics real rock samples.The transport of a monodispersed suspension is studied at different concentrations.Image analysis,velocity fieldmodeling,and pressure drop measurement are used to assess preferential clogging sites and porous medium permeability reduction,respectively.Experiments have shown that retention sites are located around preferential flow paths with relatively high flow velocities.When clogged,the pore thresholds are the deposition zones that lead to a reduction in permeability.However,pore bodies may also constitute deposition zones.Interestingly,as the concentration of the suspension increases,the kinetics of the permeability reduction are delayed,and the clogging mechanisms,as well as the type of deposit,evolve.Finally,at very high concentrations,the effects of hydrodynamic stripping are more important.These observations emphasize the role of the porous medium geometry in colloidal transport and deposition and thus permeability reduction.
基金supported by the National Natural Science Foundation of China(Grant Nos.12172104 and 11932005)the Talent Recruitment Project of Guangdong(2021QN02L892)+3 种基金the Stable Supporting Fund of Shenzhen(GXWD20231130153335002)the Shccig-Qinling Program(SMYJY202300140C)the program of Innovation Team in Universities and Colleges in Guangdong(2021KCXTD006)Development and Reform Commission of Shenzhen(XMHT20220103004).
文摘The mechanical properties of solid oxide fuel cells(SOFCs)can limit their mechanical stability and lifespan.Understanding the correlation between the microstructure and mechanical properties of porous electrode is essential for enhancing the performance and durability of SOFCs.Accurate prediction of mechanical properties of porous electrode can be achieved by microscale finite element modeling based on three-dimensional(3D)microstructures,which requires expensive 3D tomography techniques and massive computational resources.In this study,we proposed a cost-effective alternative approach to access the mechanical properties of porous electrodes,with the elastic properties of La_(0.6)Sr_(0.4)Co_(0.2)Fe_(0.8)O_(3-δc)athode serving as a case study.Firstly,a stochastic modeling was used to reconstruct 3D microstructures from two-dimensional(2D)cross-sections as an alternative to expensive tomography.Then,the discrete element method(DEM)was used to predict the elastic properties of porous ceramics based on the discretized 3D microstructures reconstructed by stochastic modeling.Based on 2D microstructure and the elastic properties calculated by the DEM modeling of the 3D reconstructed porous microstructures,a convolutional neural network(CNN)based deep learning model was built to predict the elastic properties rapidly from 2D microstructures.The proposed combined framework can be implemented with limited computational resources and provide a basis for rapid prediction of mechanical properties and parameter estimation for multiscale modeling of SOFCs.
基金supported by the Ecole des Mines Saint-Etienne and the Agence de l’Environnement et de la Maitrise de l’Energie。
文摘Pollution from road traffic contributes significantly to air pollution through pollutants from exhaust emissions(gases and particles)and non-exhaust emissions(tire wear particles,brake wear particles and the resuspension of road dust).This research examined the hazard of tire particles(TP)and in particular evaluated the effect of TP size on lung macrophages.TP were obtained by cryogenic grinding of a tire and subsequent sieving to obtain four groups of particles(TP70,TP30,TP15,TP5)of different sizes with average diameters of 107μm,55μm,22μm,and 6μm,respectively.A complete physicochemical characterization was performed to determine the size distribution,chemical composition and morphology of these particles.We then investigated the proinflammatory response,oxidative stress and cytotoxicity induced in RAW264.7 cells exposed to four different TP concentrations for 24 h.TP had no direct effect on cytotoxicity,nor did they increase reactive oxygen species(ROS)production in the cells.However,TP induced a significant and size-dependent proinflammatory effect,which was particularly pronounced with small particles.Moreover,this effect was concentration-dependent.
文摘Objectives:Cisplatin(CDDP)therapy for glioblastoma(GBM)is linked with several limitations,which include poor penetration of the blood-brain barrier(BBB),systemic toxicity,and the development of drug resistance mechanisms implicating oxidative stress dysregulation and compromised apoptotic pathways.This study evaluates C-Phycocyanin(C-PC)as a potential adjuvant to enhance CDDP efficacy by modulating redox balance and apoptosis.Methods:GBM cells(U87 and U87-EGFRvIII)were treated with CDDP,C-PC,or their combination.Cell viability was assessed by MTT assay;apoptosis was evaluated by DAPI staining andWestern blot analysis of cleaved Caspase-3 and poly(ADP-ribose)polymerase(PARP).Both intracellular and extracellular reactive oxygen species(ROS)were measured using 2′,7′-dichlorodihydrofluorescein diacetate(DCF-DA)fluorescence and lucigenin chemiluminescence,respectively.Catalase activity was quantified via hydrogen peroxide(H2O2)decomposition assay,and manganese superoxide dismutase(MnSOD)expression byWestern blot.Results:C-PCselectively decreased U87GBMcell viability while sparing normal cells.C-PC enhanced CDDP cytotoxicity,reducing viability to 26.5%vs.53.2%for CDDP alone.This effect correlated with increased apoptosis,evidenced by DNA fragmentation and higher cleaved caspase-3 and PARP levels.Combined treatment lowered ROS below survival thresholds while upregulating MnSOD and catalase activity.In U87-EGFRvIII cells,CDDP reduced viability modestly(85.2%),C-PC alone decreased viability significantly(51.5%)and induced cell death,but the combination did not further increase apoptosis.Here,C-PC’s pro-apoptotic effects,alone or with CDDP,were also associated with reduced oxidative stress in cells.Conclusion:We demonstrate that C-PC enhances CDDP cytotoxicity in sensitive U87 cells by promoting apoptosis and modulating ROS,suggesting potential for improved therapeutic efficacy with reduced systemic toxicity.Compared to the combination,C-PC monotherapy achieves superior cytotoxicity in CDDP-resistant U87-EGFRvIII cells,underscoring its potential as a standalone therapeutic approach for chemotherapy-resistant glioblastoma subtypes.
基金supported by the Paul Calas Award from the French Society of Endodontics(SFE)。
文摘This study investigates the role of Interleukin 17(IL-17)in exacerbating periapical lesions caused by Porphyromonas gingivalis(Pg)lipopolysaccharides(LPS)in the context of metabolic disease and its potential impact on glucose tolerance.Researchers developed a unique mouse model where mice were monocolonized with Pg to induce periapical lesions.After 1 month,they were fed a highfat diet(HFD)for 2 months to simulate metabolic disease and oral microbiota dysbiosis.To explore the role of LPS from Pg,wildtype(WT)mice were challenged with purified LPS from Porphyromonas gingivalis,as well as with LPS-depleted and non-depleted Pg bacteria;IL-17 knockout(KO)mice were also included to assess the role of IL-17 signaling.The impact on bone lysis,periapical injury,glucose intolerance,and immune response was assessed.Results showed that in WT mice,the presence of LPS significantly worsened bone lysis,Th17 cell recruitment,and periapical injury.IL-17 KO mice exhibited reduced bone loss,glucose intolerance,and immune cell infiltration.Additionally,inflammatory markers in adipose tissue were lower in IL-17 KO mice,despite increased dysbiosis.The findings suggest that IL-17 plays a critical role in amplifying Pg-induced periapical lesions and systemic metabolic disturbances.Targeting IL-17 recruitment could offer a novel approach to improving glycemic control and reducing type 2 diabetes(T2D)risk in individuals with periapical disease.
基金PEREN project(reference:ANR-2011-PREG-016–05)the ECOREVE project(reference:ANR-18-CE05-0036-01)the Agence Nationale de la Recherche(A.N.R.,France)for supporting these scientific works and for the financial support。
文摘The chemical and electrochemical stability of lanthanide nickelates La2 NiO4+δ(LNO),Pr2 NiO4+δ(PNO)and their mixed compounds La(2-x)PrxNiO4+δ(LPNOs)with x=0.5,1 or 1.5 is reported.The aim is to promote these materials as efficient electrodes for solid oxide fuel cell(SOFC)and/or solid oxide electrolysis cell(SOEC).La2 NiO4+δand La1.5Pr0.5NiO4+δcompounds are chemically very stable as powders over one month in the temperature range 600-800℃,while the other materials rich in praseodymium progressively decompose into various perovskite-deriving components with additional Pr6 O11.Despite their uneven properties,all these materials are quite efficient and sustainable as electrodes on top of gadolinium doped ceria(GDCBL)//yttrium doped zirconia(8 YSZ)electrolyte,for one month at 700℃without polarization.Under polarization(300 mA·cm-2),the electrochemical performances of LNO,PNO and La1.5Pr0.5NiO4+δ(LP5 NO)quickly degrade in SOFC mode,i.e.for the oxygen reduction reaction,while they show durability in SOEC mode,i.e.for the oxide oxidation reaction.
文摘The introduction of tacrolimus in clinical practice has improved patient survival after organ transplant.However,despite the long use of tacrolimus in clinical practice,the best way to use this agent is still a matter of intense debate.The start of the genomic era has generated new research areas,such as pharmacogenetics,which studies the variability of drug response in relation to the genetic factors involved in the processes responsible for the pharmacokinetics and/or the action mechanism of a drug in the body.This variability seems to be correlated with the presence of genetic polymorphisms.Genotyping is an attractive option especially for the initiation of the dosing of tacrolimus;also,unlike phenotypic tests,the genotype is a stable characteristic that needs to be determined only once for any given gene.However,prospective clinical studies must show that genotype determination before transplantation allows for better use of a given drug and improves the safety and clinical efficacy of that medication.At present,research has been able to reliably show that the CYP3A5 genotype,but not the CYP3A4 or ABCB1 ones,can modify the pharmacokinetics of tacrolimus.However,it has not been possible to incontrovertibly show that the corresponding changes in the pharmacokinetic profile are linked with different patient outcomes regarding tacrolimus efficacy and toxicity.For these reasons,pharmacogenetics and individualized medicine remain a fascinating area for further study and may ultimately become the face of future medical practice and drug dosing.
基金financial support from the French National Research Agency(project ANR-17-CE05-0023)。
文摘The vanadium redox flow battery(VRFB)has been receiving great attention in recent years as one of the most viable energy storage technologies for large-scale applications.However,higher concentrations of vanadium species are required in the H_(2)O-H_(2)SO_(4) electrolyte in order to improve the VRFB energy density.This might lead to unwanted precipitation of vanadium compounds,whose nature has not been accurately characterized yet.For this purpose,this study reports the preparation ofⅤ^((Ⅱ)),ⅤV^((Ⅲ)),Ⅴ^((Ⅳ))andⅤ^((Ⅴ))supersaturated solutions in a 5 M H_(2)SO_(4)-H_(2)O electrolyte by an electrolytic method,from the only vanadium sulfate compound commercially available(VOSO_(4)).The precipitates obtained by ageing of the stirred solutions are representative of the solids that may form in a VRFB operated with such supersaturated solutions.The solid phases are identified using thermogravimetric analysis,X-ray diffraction and SEM.We report that dissolvedⅤ^((Ⅱ)),Ⅴ^((Ⅲ))andⅤ^((Ⅳ))species precipitate as crystals of VSO_(4),V_(2)(SO_(4))3 and VOSO_(4) hydrates and not in their anhydrous form;conversely V^((Ⅴ))precipitates as an amorphous V_(2) O_(5) oxide partially hydrated.The measured hydration degrees(respectively 1.5,9,3 and 0.26 mol of H_(2)O per mol of compound)might significantly affect the overall engineering of VRFB operating with high vanadium concentrations.
基金financial support from the National Natural Science Foundation of China(Grant No.U1760206)the National Key R&D Program of China(Grant No.2017YFE0107900)+1 种基金the 111 Project 2.0 of China(Grant No.BP0719037)the financial support provided by the ESA-MAP MICAST project contract 14347/01/NL/SH.
文摘A volume averaged columnar solidification model,which couples the flow,temperature and solute concentration fields,is applied to simulate experimental continuous casting cases with and without vertical electromagnetic stirring(V-EMS).The calculated distribution of magnetic induction intensity and final macrosegregation maps are consistent with the experimental results.Calculation results reveal that the V-EMS promotes longitudinal melt flow,accelerates heat dissipation and solidification and finally reduces the central segregation of carbon.However,when V-EMS is applied,the solute distribution becomes asymmetric because the melt flow shows opposite directions between the near and far sides from stirrer.An obvious positive segregation band is observed at about 1/4 width of the billet near the stirrer in both calculated and experimental results.The position and degree of such positive segregation could be affected by installation height of stirrer,as demonstrated by additional simulation cases.
基金FAPEMIG (PPM X 45-16)CNPqpartially funded by CNPq 308035/2013-5
文摘Projections of climate change are essential to guide sustainable development plans in the tropical Andean countries such as Peru. This study assessed the projections of precipitation and potential evaporation, rain erosive potential, and precipitation concentration in the Mantaro River Basin, in the Peruvian Andes, which is important for agriculture and energy production in Peru. We assumed the Intergovernmental Panel on Climate Change （IPCC） AIB greenhouse gas emission scenario and simulated the global climate change by the HadCM3 global climate model. Due to the steepness of the mountain slopes and the narrowness of the river valley, this study uses the downscaling of the global model simulations by the regional Eta model down to 2o-km resolution. The downscaling projections show decrease in the monthly precipitation with respect to the baseline period, especially during the rainy season, between February and April, until the end of the 21st century. Meanwhile, a progressive increase in the monthly evaporation from the baseline period is projected. The Modified Fournier Index （MFI） shows a statistically significant downward trend in the Mantaro River Basin, whieh suggests a possible reduction in the rain erosive potential. The Precipitation Concentration Index （PCI） shows a statistically significant increasing trend, which indicates increasingly more irregular temporal distribution of precipitation towards the end of the century. The results of this study allow us to conclude that there should be a gradual increase in water deficit and precipitation concentration. Both changes can be negative for agriculture, power generation, and water supply in the Mantaro River Basin in Peru.
文摘The present study focuses on the impacts of extreme drought and flooding situations in Amazonia, using level/discharge data from some rivers in the Amazon region as indicators of impacts. The last 10 years have featured various “once in a century” droughts and floods in the Amazon basin, which have affected human and natural systems in the region. We assess a history of such hazards based on river data, and discuss some of the observed impacts in terms of vulnerability of human and natural systems, as well as some of adaptation strategies implemented by regional and local governments to cope with them. A critical perspective of mitigation of drought and flood policies in Amazonia suggests that they have been mostly ineffective in reducing vulnerability for the majority of the population, constituting, perhaps, examples of maladaptation via the undermining of resilience.
基金Item Sponsored by the French Agency for Environment and Energy (ADEME) as Part of the ISOPEM Project and labelled by TENERRDIS (Rhone-Alpes Energy Cluster)
文摘This paper proposes an estimate of the stirring intensity needed to maintain an efficient segregation of impurities towards the liquid when crystallizing semiconductors such as silicon,with rapid solidification rates(several cm/h).The method,valid far from stagnation points or detachments,is based on the properties of turbulent boundary layers,with a normal velocity of the liquid towards the solid/liquid interface due to solidification,that has the same effect as boundary layer suction in aeronautics.The transition between the diffusive regime(no segregation),and the convective regime(efficient segregation)occurs if the friction at the wall is greater than a threshold depending on the solidification rate.A chart is given to estimate the convecto-diffusive parameter from the ratio between stirring and solidification velocity,and the Reynolds number.
文摘A deep understanding of the physical processes coming along with the current interruption in high voltage circuit breakers is essential for the optimization of today’s switching technologies.Therefore a switching arc in a model circuit breaker is studied by means of computational fluid dynamics(CFD)simulations and optical emission spectroscopy(OES)in this contribution.Experimental investigations are performed in carbon dioxide(CO2)at absolute filling pressures of 0.1 and 0.5 MPa.CFD simulations are carried out based on a model of the arcing zone including a consistent treatment of the radiation transport and the wall ablation.Carbon ion line radiation is analysed in the experiment using an optical path in the heating channel between the electrodes inside the nozzle system.The pressure value in the arc is estimated based on the line width-intensity dependence.Obtained values correspond to the measured pressure outside the arc.For the temperature profiles,a good agreement within the accuracy of the approaches is observed between the CFD simulations and the results of OES.
基金Project(2009AA033501)supported by the National Hi-tech Research and Development Program of ChinaProject(2006BAE04B01-2)supported by the National Key Technology Research&Development Program of ChinaProject(06SR07104)supported by theInternational Cooperation Fund of Shanghai Science and Technology Committee,Shanghai/Rhone-Alpes Science and Technology
文摘The solution-treated Mg-4Y-4Sm-0.5Zr alloy was extruded at temperatures from 325℃ to 500℃.Dynamic recrystallization(DRX) completely occurs when the alloy is extruded at 350℃and above.The grains of the extruded alloy are obviously refined by the occurrence of DRX.The average grain size of the extruded alloy increases with increasing the extrusion temperature,leading to a slight decrease of the ultimate tensile strength(UTS) and the yield strength(YS) .On the contrary,the UTS and YS of the extruded and aged alloy increase with increasing the extrusion temperature.Values of UTS of 400 MPa,YS larger than 300 MPa and elongation(EL) of 7%are achieved after extrusion at 400℃ and ageing at 200℃ for 16 h.Both grain refinement and precipitation are efficient strengthening mechanisms for the Mg-4Y-4Sm-0.5Zr alloy.
基金financial support from CAPES–Coordination for the Improvement of Higher Education Personnelfrom CEFET-MG–Federal Center for Technological Education of Minas Gerais+1 种基金from CNPQ–National Council for Scientific and Technological Development(Nos.406841/2016-0 and 301338/2016-7)from FAPESP–Sao Paulo Research Foundation(Nos.2016/24561-0,2019/184805,and 2018/07377-6)。
文摘In the restricted three-body problem,the traditional Lagrange points L1 and L2 are the only equilibrium points near the asteroid 243 Ida.The thrust generated by a solar sail over a spacecraft enables the existence of new artificial equilibrium points,which depend on the position of the spacecraft with respect to the asteroid and the attitude of the solar sail.Such equilibrium points generate new spots to observe the body from above or below the plane of motion.Such points are very good observational locations due to their stationary condition.This work provides a preliminary analysis to observe Ida through the use of artificial equilibrium points as spots combined with transfer maneuvers between them.Such combination can be used to observe the asteroid from more different points of view in comparison to fixed ones.The analyses are made for a spacecraft equipped with a solar sail and capable of performing bi-impulsive maneuvers.The solar radiation pressure is used both to maintain the equilibrium condition and to reduce the costs of the transfers and/or to create transfers with longer duration.This is a new aspect of the present research,because it combines the continuous thrust with initial and final small impulses,which are feasible for most of the spacecraft,because the magnitudes of the impulses are very low.These combined maneuvers may reduce the transfer times of the maneuvers in most of the cases,compared with the maneuvers based only on continuous thrust.Several options involved in these transfers are shown,like to minimize the fuel spent(Dv)as a function of the transfer time or to extend the duration of the travel between the points.Extended transfer times can be useful when observations are required during the transfers.
基金LGP2 is part of the LabEx Tec 21(Investissements d’Avenir-grant agreement n°ANR-11-LABX-0030)of the PolyNat Carnot Institut(Investissements d’Avenir-grant agreement n°ANR-11-CARN-030-01).
文摘Cellulose is the most abundant biomass material in nature and it is mainly extracted from natural or lignocellulosic fibers.After purification,cellulose fibers exhibit two interesting features for their further transformation into nanomaterials:a hierarchical and multi-level strcture,and a semicrystalline microstructure.Different forms of cellulose nanomaterials,resulting from a top-down deconstructing strategy(cellulose nanocrystals(CNCs),cellulose nanofibrils(CNFs))or bottom-up strategy(bacterial cellulose(BC))can be prepared.Multiple mechanical shearing actions applied to cellulosic fibers release more or less the nanofibrils individually.A controlled strong acid hydrolysis treatment can be applied to cellulosic fibers allowing dissolution of non-crystalline domains.Such cellulose nanomaterials have been the focus of an exponentially increasing number of works or reviews devoted to understand such materials and their applications.They have a high potential for an emerging industry.In the nanoscale,cellulose exhibits specific properties broadening the applications of this naturally occurring polymer.An overview of existing methods for the preparation of cellulose nanomaterials and their specific properties that outperform and contrast with cellulose in the microscale is proposed.
文摘In the context of the Cigeo project,the French National Radioactive Waste Management Agency(Andra)is studying the behaviour of a deep geological facility for radioactive waste deposit in the CallovoOxfordian(COx)claystone.The assessment of durability of this project requires the prediction of irreversible strain over a large time scale.The mechanical interaction of the host rock and the concrete support of tunnels must be investigated to ensure the long-term sustainability of the structure.The instantaneous and time-dependent behaviour of the claystone-concrete interface is experimentally investigated with direct shear tests and long-duration shear tests of a few months.The mechanical and structural state of the claystone which is affected after interaction with concrete reflects to the response of the claystone-concrete interface,and thus different types of COx claystone-concrete interfaces are tested.The delayed deformation of the interface is found to be linked to the level of the normal loading and the loading history while a different response of the interface was observed from the short-and long-duration tests,indicating a possible progressive modification of interface under long-duration loadings.
基金funded by the Deutsche Forschungsgemeinschaft(DFG,German Research Foundation)–Project No.454848899。
文摘Double-pulse LIBS is a promising technique for deep-sea applications.LIBS measurements in shallow water with up to 400 mJ each pulse were done to select laser parameters which promote optimized spectral line emission from plasma even at elevated pressures,where line broadening until loss of most of the spectral information can occur.Optical emission spectroscopy,using a Czerny-Turner spectrometer,has been applied to investigate the dependence of the emitted radiation on laser parameters and hydrostatic pressure.It has been found,that higher laser pulse energies,especially with short pulse delay as required in high water pressure,can also have an adverse effect on the measured spectrum.
