The mechanical and thermodynamic properties of W-Ti alloys(including W_(15)Ti_(1),W_(14)Ti_(2),W_(12)Ti_(4) and W_(8)Ti_(8) alloys)were investigated by the first-principles approach based on density functional theory....The mechanical and thermodynamic properties of W-Ti alloys(including W_(15)Ti_(1),W_(14)Ti_(2),W_(12)Ti_(4) and W_(8)Ti_(8) alloys)were investigated by the first-principles approach based on density functional theory.The results indicate that W-Ti alloys except W_(8)Ti_(8) are thermodynamically stable.The modulus and hardness of W-Ti alloys are smaller than those of pure tungsten and gradually decrease with increasing Ti concentration.However,their B/G ratios and Poisson's ratios exceed those of pure tungsten,suggesting that the introduction of Ti decreases the mechanical strength while enhancing the ductility of W-Ti alloys.The thermal expansion coefficients for W-Ti alloys all surpass those of pure tungsten,indicating that the introduction of titanium exacerbates the thermal expansion behavior of W-Ti alloys.Nevertheless,elevated pressure has the capacity to suppress the thermal expansion tendencies in titanium-doped tungsten alloys.This study offers theoretical insights for the design of nuclear materials by exploring the mechanical and thermodynamic properties of W-Ti alloys.展开更多
In this paper,the effect of sodium laurate(SL)on the properties of sodium lauroyl glutamate(SLG),such as surface activity,foam,wetting,emulsification,and resistance to hard water,has been systematically investigated.T...In this paper,the effect of sodium laurate(SL)on the properties of sodium lauroyl glutamate(SLG),such as surface activity,foam,wetting,emulsification,and resistance to hard water,has been systematically investigated.The results showed that the critical micelle concentration(cmc)of SLG was 0.30 mmol/L,and the surface tension at the cmc(γcmc)was 34.95 mN/m.With the increase of SL content,the efficiency of SLG solution in reducing the surface tension was decreased.When the SL content was increased,there was no significant change in the foaming ability and foam stability of SLG solutions.The increase of SL content improved both the emulsification and wettability of SLG,but reduced its water resistance.展开更多
Carbon fibre,steel fibre and graphite were used as conductive fillers to prepare cementitious materials with excellent electrothermal properties.The electrically conductive cementitious materials with different volume...Carbon fibre,steel fibre and graphite were used as conductive fillers to prepare cementitious materials with excellent electrothermal properties.The electrically conductive cementitious materials with different volume dosages were analysed through compressive and flexural strength,electrochemical impedance spectroscopy and temperature rise tests.An equivalent circuit model was established to study the electrically conductive heat generation mechanism in the electrically conductive cementitious composites.The results indicate that the mechanical properties of cementitious composite materials with a ternary conductive phase are better than those of pristine cementitious materials because the fibrous filler improves their mechanical properties.However,the incorporation of graphite in the material reduces its strength.Introducing fibrous and point-like conductive phase materials into the cementitious material enhances the overall conductive pathway and considerably reduces the electrical resistance of the cementitious material,enhancing its conductive properties.The volume ratios of carbon fibre,steel fibre and graphite that achieve an optimal complex doping in the cementitious material were 0.35%,0.6%and 6%,respectively.This was determined using the mutation point of each circuit element parameter as the percolation threshold.In addition,at a certain safety voltage,there is a uniform change between the internal and surface temperatures of the conductive cementitious material,and the heating effect in this materialis is considerably better than that in the pristine cementitious material.展开更多
Although poly(lactic acid)(PLA)is a good environmentally-friendly bio-degradable polymer which is used to substitute traditional petrochemical-based polymer packaging films,the barrier properties of PLA films are stil...Although poly(lactic acid)(PLA)is a good environmentally-friendly bio-degradable polymer which is used to substitute traditional petrochemical-based polymer packaging films,the barrier properties of PLA films are still insufficient for high-barrier packaging applications.In this study,oxygen scavenger hydroxyl-terminated polybutadiene(HTPB)and cobalt salt catalyst were incorporated into the PLA/poly(butylene adipate-co-terephthalate)(PLA/PBAT),followed by melting extrusion and three-layer co-extrusion blown film process to prepare the composite films.The oxygen permeability coefficient of the composite film combined with 6 wt%oxygen scavenger and 0.4 wt%catalyst was decreased significantly from 377.00 cc·mil·m^(-2)·day^(-1)·0.1 MPa^(-1) to 0.98 cc·mil·m^(-2)·day^(-1)·0.1 MPa^(-1),showing a remarkable enhancement of 384.69 times compared with the PLA/PBAT composite film.Meanwhile,the degradation behavior of the composite film was also accelerated,exhibiting a mass loss of nearly 60%of the original mass after seven days of degradation in an alkaline environment,whereas PLA/PBAT composite film only showed a mass loss of 32%.This work has successfully prepared PLA/PBAT composite films with simultaneously improved oxygen barrier property and degradation behavior,which has great potential for high-demanding green chemistry packaging industries,including food,agricultural,and military packaging.展开更多
In order to achieve the large-scale application of manufactured sand in railway high-strength concrete structure,a series of high-strength manufactured sand concrete(HMC)are prepared by taking the manufactured sand li...In order to achieve the large-scale application of manufactured sand in railway high-strength concrete structure,a series of high-strength manufactured sand concrete(HMC)are prepared by taking the manufactured sand lithology(tuff,limestone,basalt,granite),stone powder content(0,5%,10%,15%)and concrete strength grade(C60,C80,C100)as variables.The evolution of mechanical properties of HMC and the correlation between cubic compressive strength and other mechanical properties are studied.Compared to river sand,manufactured sand enhances the cubic compressive strength,axial compressive strength and elastic modulus of concrete,while its potential microcracks weaken the flexural strength and splitting tensile strength of concrete.Stone powder content displays both positive and negative effects on mechanical properties of HMC,and the stone powder content is suggested to be less than 10%.The empirical formulas between cubic compressive strength and other mechanical properties are proposed.展开更多
The microstructures and thermodynamic properties of mixed systems comprising pyridinium ionic liquid[HPy][BF_(4)]and acetonitrile at different mole fractions were studied using molecular dynamics simulation in this wo...The microstructures and thermodynamic properties of mixed systems comprising pyridinium ionic liquid[HPy][BF_(4)]and acetonitrile at different mole fractions were studied using molecular dynamics simulation in this work.The following properties were determined:density,self-diffusion coefficient,excess molar volume,and radial distribution function.The results show that with an increase in the mole fraction of[HPy][BF_(4)],the self-diffusion coefficient decreases.Additionally,the excess molar volume initially decreases,reaches a minimum,and then increases.The rules of radial distribution functions(RDFs)of characteristic atoms are different.With increasing the mole fraction of[HPy][BF_(4)],the first peak of the RDFs of HA1-F decreases,while that of CT6-CT6 rises at first and then decreases.This indicates that the solvent molecules affect the polar and non-polar regions of[HPy][BF_(4)]differently.展开更多
Since the discovery of carbon dots(CDs)in 2004,the unique photoluminescence phenomenon of CDs has attracted widespread attention.However,the molecular weight of CDs has not been adequately quantified at present,due to...Since the discovery of carbon dots(CDs)in 2004,the unique photoluminescence phenomenon of CDs has attracted widespread attention.However,the molecular weight of CDs has not been adequately quantified at present,due to CDs are atomically imprecise and their molecular weight distribution is broad.In this paper,a series of Pluronic-modified CDs were prepared and the structure of the CDs was briefly analyzed.Subsequently,a molecular weight measurement method based on colligative properties was developed,and the correction coefficient in the algorithm was briefly analyzed.The calculated molecular weight was applied to the determination of surface adsorption capacity.This work provided a method for averaging the molecular weight of atomically imprecise particulate materials,which is expected to provide new opportunities in related fields.展开更多
Observational data of ball lightning often contradict each other, so it was sometimes proposed to build a theory of ball lightning based on only a small number of statistically reliable observations. Work on this prin...Observational data of ball lightning often contradict each other, so it was sometimes proposed to build a theory of ball lightning based on only a small number of statistically reliable observations. Work on this principle did not bring results. The correct approach to creating the theory of ball lightning should be the desire to explain all of its properties, even those that are rare. In the database of ball lightning observations, the most valuable are the cases when it left traces available for quantitative analysis, or was filmed by video cameras. Ball lightning is a material body consisting of a shell and a multi-element core. Cases of water heating made it possible to determine energy density of ball lightning, which turned out to be higher than 1010 J/m3. A study of results of ball lightning explosion, as well as its effect on snow, made it possible to assume that it is capable of generating radiation with a wavelength of about 10 cm, the power of which can be greater than 120 kW. Ball lightning has an electric charge of 10−3 - 10−1 C. The presence of an electric charge explains the complex nature of its movement in atmosphere. Ball lightning is formed under the action of magnetic field pulse and ultraviolet radiation of linear lightning channel. A model of ball lightning in the form of a core of charged “dynamic capacitors” and a shell of polarized water molecules is considered. It is shown that this shell is capable of withstanding the force of Coulomb repulsion of the core charges and the pressure caused by the movement of charge carriers. The glow of ball lightning core occurs due to orbital motion of electrons at a speed close to light speed. The intensity of the glow is determined by the degree of uniformity of electrons arrangement along the orbit.展开更多
Edible mushroom proteins are the promising ones with the advantages of complete essential amino acid profile and multiple functional activities.To reinforce their applications in functional food development,this study...Edible mushroom proteins are the promising ones with the advantages of complete essential amino acid profile and multiple functional activities.To reinforce their applications in functional food development,this study comprehensively evaluated the physicochemical and functional properties of protein isolates from 5 mushroom species,i.e.,Pleurotus eryngii(PEP),Pleurotus ostreatus(POP),Lentinula edodes(LEP),Flammulina velutipes(FVP)and Hypsizygus marmoreus(HMP).Results showed that PEP,LEP,FVP,POP and HMP exhibited better protein solubility(PS),water holding capacity(WHC),emulsification activity index(EAI),and foaming capacity(FC)than those of soybean protein and pea protein isolates(PPI).PEP(51.95%)and POP(49.15%)had a higher amount ofβ-sheet structure.Principal component analysis and correlation analysis showed that the seven proteins could be divided into 3 clusters,and WHC,EAI and FC were significantly positively correlated with PS andβ-sheet.The least gelation concentration of PEP(16%)and FVP(16%)at p H 6.0 and 7.0 was similar to PPI,and PEP showed better hardness,springiness and rheological properties than other proteins gels.Overall,our study showed that 5 edible mushroom proteins possessed excellent functionalities(except for gelling capacity),which provided novel insights on unexploited sources of mushroom proteins used as protein-based foods in the food industry.展开更多
The mechanical behavior of cemented gangue backfill materials(CGBMs)is closely related to particle size distribution(PSD)of aggregates and properties of cementitious materials.Consequently,the true triaxial compressio...The mechanical behavior of cemented gangue backfill materials(CGBMs)is closely related to particle size distribution(PSD)of aggregates and properties of cementitious materials.Consequently,the true triaxial compression tests,CT scanning,SEM,and EDS tests were conducted on cemented gangue backfill samples(CGBSs)with various carbon nanotube concentrations(P_(CNT))that satisfied fractal theory for the PSD of aggregates.The mechanical properties,energy dissipations,and failure mechanisms of the CGBSs under true triaxial compression were systematically analyzed.The results indicate that appropriate carbon nanotubes(CNTs)effectively enhance the mechanical properties and energy dissipations of CGBSs through micropore filling and microcrack bridging,and the optimal effect appears at P_(CNT)of 0.08wt%.Taking PSD fractal dimension(D)of 2.500 as an example,compared to that of CGBS without CNT,the peak strength(σ_(p)),axial peak strain(ε_(1,p)),elastic strain energy(Ue),and dissipated energy(U_(d))increased by 12.76%,29.60%,19.05%,and90.39%,respectively.However,excessive CNTs can reduce the mechanical properties of CGBSs due to CNT agglomeration,manifesting a decrease inρ_(p),ε_(1,p),and the volumetric strain increment(Δε_(v))when P_(CNT)increases from 0.08wt%to 0.12wt%.Moreover,the addition of CNTs improved the integrity of CGBS after macroscopic failure,and crack extension in CGBSs appeared in two modes:detour and pass through the aggregates.Theσ_(p)and U_(d)firstly increase and then decrease with increasing D,and porosity shows the opposite trend.Theε_(1,p)andΔε_(v)are negatively correlated with D,and CGBS with D=2.150 has the maximum deformation parameters(ε_(1,p)=0.05079,Δε_(v)=0.01990)due to the frictional slip effect caused by coarse aggregates.With increasing D,the failure modes of CGBSs are sequentially manifested as oblique shear failure,"Y-shaped"shear failure,and conjugate shear failure.展开更多
Peanut varieties are diverse globally,with their characters and nutrition determining the product quality.However,the comparative analysis and statistical analysis of key quality indicators for peanut kernels across t...Peanut varieties are diverse globally,with their characters and nutrition determining the product quality.However,the comparative analysis and statistical analysis of key quality indicators for peanut kernels across the world remains relatively limited,impeding the comprehensive evaluation of peanut quality and hindering the industry development on a global scale.This study aimed to compare and analyze the apparent morphology,microstructure,single-cell structure,engineering and mechanical properties,as well as major nutrient contents of peanut kernels from 10 different cultivars representing major peanut-producing countries.The surface and cross-section microstructure of the peanut kernels exhibited a dense“blocky”appearance with a distinct cellular structure.The lipid droplets were predominantly spherical with a regular distribution within the cells.The single-cell structure of the kernels from these 10 peanut cultivars demonstrated varying morphologies and dimensions,which exhibited correlations with their mechanical and engineering properties.Furthermore,the mass loss versus temperature profiles of the peanut kernels revealed five distinct stages,corresponding to moisture loss,volatile loss,protein denaturation,and the degradation of various biomacromolecules.Variations were also observed in the lipid,protein,and sucrose contents,texture,bulk density,true density,porosity,geometric mean diameter,and sphericity among the diferent peanut varieties.This study establishes relationships and correlations among microstructure,engineering properties,and nutritional composition of commonly grown peanut varieties in major peanut-processing countries.The findings provide valuable insights into peanut quality evaluation,empowering the peanut industry to enhance their processing and product development efforts.展开更多
Graphene nanoplatelets(GNPs)have attracted tremendous interest due to their unique properties and bonding capabilities.This study focuses on the effect of GNP dispersion on the mechanical,thermal,and morphological beh...Graphene nanoplatelets(GNPs)have attracted tremendous interest due to their unique properties and bonding capabilities.This study focuses on the effect of GNP dispersion on the mechanical,thermal,and morphological behavior of GNP/epoxy nanocomposites.This study aims to understand how the dispersion of GNPs affects the properties of epoxy nanocomposite and to identify the best dispersion approach for improving mechanical performance.A solvent mixing technique that includes mechanical stirring and ultrasonication was used for producing the nanocomposites.Fourier transform infrared spectroscopy was used to investigate the interaction between GNPs and the epoxy matrix.The measurements of density and moisture content were used to confirm that GNPs were successfully incorporated into the nanocomposite.The findings showed that GNPs are successfully dispersed in the epoxy matrix by combining mechanical stirring and ultrasonication in a single step,producing well-dispersed nanocomposites with improved mechanical properties.Particularly,the nanocomposites at a low GNP loading of 0.1 wt%,demonstrate superior mechanical strength,as shown by increased tensile properties,including improved Young's modulus(1.86 GPa),strength(57.31 MPa),and elongation at break(4.98).The nanocomposite with 0.25 wt%GNP loading performs better,according to the viscoelastic analysis and flexural properties(113.18 MPa).Except for the nanocomposite with a 0.5 wt%GNP loading,which has a higher thermal breakdown temperature,the thermal characteristics do not significantly alter.The effective dispersion of GNPs in the epoxy matrix and low agglomeration is confirmed by the morphological characterization.The findings help with filler selection and identifying the best dispersion approach,which improves mechanical performance.The effective integration of GNPs and their interaction with the epoxy matrix provides the doorway for additional investigation and the development of sophisticated nanocomposites.In fields like aerospace,automotive,and electronics where higher mechanical performance and functionality are required,GNPs'improved mechanical properties and successful dispersion present exciting potential.展开更多
Soil cement bentonite(SCB)is a common material for constructing vertical cutoff walls to prevent groundwater migration at contaminated industrial sites.However,site contaminants can degrade the durability of the cutof...Soil cement bentonite(SCB)is a common material for constructing vertical cutoff walls to prevent groundwater migration at contaminated industrial sites.However,site contaminants can degrade the durability of the cutoff wall.To enhance its performance,this study developed a silica fume-SCB(SSCB).The macroscopic and microscopic properties of SSCB were assessed by unconfined compressive strength test,variable head permeability test,X-ray diffraction(XRD),scanning electron microscopy(SEM)and nuclear magnetic resonance(NMR)spectroscopy.The correlation between its multi-scale properties was analyzed based on pore characteristics.The results indicate that increasing the silica fume substitution ratio improved SSCB strength,especially in the middle and late curing stages.Moreover,increasing the substitution ratio decreased SSCB permeability coefficient,with a more pronounced effect in earlier curing stages.Silica fume addition also refined SSCB pore structure and reduced its porosity.The fractal dimension was used to quantify SSCB pore structure complexity.Increasing silica fume content reduced small pore fractal dimension in SSCB.Concurrently,SSCB strength increased and SSCB permeability coefficient decreased.The findings of this research will demonstrate the great potential of SSCB backfill for practical applications.展开更多
Polyethylene glycol(PEG)with different chains was used to modify epoxy asphalt.Molecular models of PEG⁃modified epoxy asphalt were developed using molecu⁃lar simulations(MS).The thermodynamic and mechanical properties...Polyethylene glycol(PEG)with different chains was used to modify epoxy asphalt.Molecular models of PEG⁃modified epoxy asphalt were developed using molecu⁃lar simulations(MS).The thermodynamic and mechanical properties of PEG⁃modified epoxy asphalt were analyzed,and its toughening mechanisms were explored.A method based on the Dijkstra algorithm was proposed to evaluate ep⁃oxy asphalt crosslinked networks.The results show that the introduction of PEG chains into epoxy asphalt can lower the glass transition temperature and enhance its toughness be⁃cause of the extended length of the PEG chains,which can in⁃crease the free volume and improve the mobility of the epoxy resin in the epoxy asphalt.The crosslinked network quantita⁃tive evaluation method based on the Dijkstra algorithm can ef⁃fectively evaluate the distribution of epoxy asphalt crosslink⁃ing bonds,providing further explanation of the toughening mechanism of PEG⁃modified epoxy asphalt.The feasibility of designing and screening epoxy asphalt materials by MS is verified,and a guide for toughening mechanism research of epoxy asphalt at the molecular level is provided.展开更多
This study focuses on the thermophysical characterizations of composite materials made from polypropylene reinforced with residues and fibers from Borassus wood from Chad. These properties are experimentally determine...This study focuses on the thermophysical characterizations of composite materials made from polypropylene reinforced with residues and fibers from Borassus wood from Chad. These properties are experimentally determined at different temperatures using the hot wire method of the “FP2C” machine, where the hot wire probe is inserted between two specimens. The values of the thermal conductivity in powdered Borassus wood range from 0.170 W/mK to 0.182 W/mK for female wood (FNTF) and from 0.169 W/mK to 0.173 W/mK for male wood. For the female and male fibers, the thermal conductivity values range from 0.137 W/mK to 0.157 W/mK for the female and from 0.138 W/mK to 0.168 W/mK for the male. The thermal effusivity of the residues and fibers of Borassus wood varies from: 509.6 Ws1/2/m2K to 543 Ws1/2/m2K for the powder of female wood and from 524.6 Ws1/2/m2K to 547 Ws1/2/m2K for the powder of male wood. For the fibers of Borassus wood, the values range from 410.6 Ws1/2/m2K to 523.6 Ws1/2/m2K for the female wood fibers and from 420.3 Ws1/2/m2K to 480.3 Ws1/2/m2K for the male wood fibers. These results are important for the applications of Borassus wood residues and fibers in construction works regarding the thermal insulation of habitats.展开更多
This study investigates the surface properties of the dissimilar AA7075/Mg-WE43 joints wherein the effect of positioning the AA7075 on the advancing or retreating sides during friction stir welding(FSW)was scrutinized...This study investigates the surface properties of the dissimilar AA7075/Mg-WE43 joints wherein the effect of positioning the AA7075 on the advancing or retreating sides during friction stir welding(FSW)was scrutinized.The EBSD analysis revealed that the average grain size reduced from 4.11±0.7μm to 2.04±0.9μm when AA7075 was shifted from advancing to retreating side.The results showed that positioning AA7075 on the retreating side significantly reduced the wear rate from 0.41 mm^(3)/Nm to 0.27 mm^(3)/Nm and mitigates the problem of brittle intermetallic compound(IMC)formation,consequently reducing the average microhardness.Corrosion resistance improved from 77.59 mpy to 56.299 mpy.The higher grain refinement improved wear resistance due to higher grain boundary density and greater chances of formation of protective oxide films.The current work thus enhances the practical applicability of AA7075/Mg-WE43 welds for lightweighting of automotive structures.展开更多
Scorpions are distributed almost all over the world and inhabit rainforests,deserts,mountains,and littoral zones.Their multifunctional chelae play a key role in their biology.The chela is the pincer that has originate...Scorpions are distributed almost all over the world and inhabit rainforests,deserts,mountains,and littoral zones.Their multifunctional chelae play a key role in their biology.The chela is the pincer that has originated from the last two segments of the pedipalp.Many previous studies have focused on the morphology of the chela and the overall pincer force.The knowledge about the material properties of scorpion chelae remains rather poor.In particular,little is known about the spines located on the grasping edge of the chela.In this study,we use a combination of nanoindentation,micro-computer tomography,confocal laser scanning microscopy,scanning electron microscopy and energy-dispersive X-ray elemental analysis,to examine the mechanical properties,relative density,sclerotization level,microstructure and biomineralization of both the regular cuticle and the spine cuticle of the chela in the scorpion Androctonus bicolor.Our results show that the mechanical property values of the spine cuticle are significantly higher than those of the regular cuticle.This can reduce the risk of damage to the chela,increase the chance of indentation into the prey tissue and is very likely to result from both higher sclerotization level and biomineralization due to the accumulation of zinc.The specialized microstructure of the cuticle could contribute to the enhancement of the stiffness,strength and toughness of the chela.This study aids in better understanding the material structure,composition and properties of the scorpion chela cuticle.展开更多
With the rapid development of the world economy,complex air pollution has increasingly become a serious threat;for example,with haze events occurring frequently in various regions of the globe.Recent evidence has indi...With the rapid development of the world economy,complex air pollution has increasingly become a serious threat;for example,with haze events occurring frequently in various regions of the globe.Recent evidence has indicated that secondary aerosols play an important role in haze formation,and that heterogeneous processes are among the main forces driving their explosive growth.In this regard,this paper reviews recent advances in the understanding of the impact of heterogeneous processes on haze chemistry,including the impact on NO_(2)chemistry,marine aerosols,and the hygroscopicity and optical properties of atmospheric aerosols.It is distinguished from past reviews on this topic by focusing mainly on new insights from the past five years.We summarize the main findings of the impacts of heterogeneous processes on NO_(2)chemistry,marine aerosols,and the physicochemical properties of atmospheric aerosols,and propose several future research directions.展开更多
Cr_(2)O_(3)was used as grain inhibitor in Ti(C,N)-based cermets with vacuum sintering.The microstructure and mechanical and tribological properties of cermets with Cr_(2)O_(3)and Cr_(3)C_(2)were investigated.The resul...Cr_(2)O_(3)was used as grain inhibitor in Ti(C,N)-based cermets with vacuum sintering.The microstructure and mechanical and tribological properties of cermets with Cr_(2)O_(3)and Cr_(3)C_(2)were investigated.The results show that adding Cr_(2)O_(3)promotes a gray core/gray rim structure formation and finer size of Ti(C,N)hard phase.Compared with the cermet with an equal Cr_(3)C_(2)addition,the cermet with 0.6 wt.%Cr_(2)O_(3)exhibits 16.5%higher transverse rupture strength.This enhancement is likely due to the smaller lattice misfit at the core/rim interface and more uniform Cr distribution in the binder.Additionally,at room temperature(25℃)and 800℃,Cr_(2)O_(3)-containing cermets demonstrate lower coefficients of friction and volume wear ratios than Cr_(3)C_(2)-containing cermets,with the wear ratio difference reaching an order of magnitude.Scanning electron microscopy and X-ray photoelectron spectroscopy results further confirm more oxidation wear in Cr_(2)O_(3)-containing cermets than in Cr_(3)C_(2)-containing cermets.展开更多
Furfurylation,a renowned chemical modification technique,uses furfuryl alcohol to enhance the properties of wood.This technology can be further refined by incorporating renewable tannins,which promote cross-linking wi...Furfurylation,a renowned chemical modification technique,uses furfuryl alcohol to enhance the properties of wood.This technology can be further refined by incorporating renewable tannins,which promote cross-linking with furfuryl alcohol.This study investigates the effects of furfurylation and tannin-modified furfurylation on the physical and mechanical properties of tropical Gmelina wood(Gmelina arborea Roxb.).Experiments involved impregnating Gmelina wood with aqueous solutions of furfuryl alcohol(FA)at 40%and 70%concentrations,as well as FA-tannin combinations(FA 40%-TA and FA 70%-TA),followed by polymerization at 103℃.The results demonstrated that both FA and FA-tannin treatments significantly improved the wood’s physical and mechanical properties.Notably,FA-tannin treatments achieved anti-swelling efficiency comparable to FA alone.However,the addition of tannins(FA 70%-TA)enhanced leaching resistance by up to 47%,contributing to a more environmentally sustainable modification process.Mechanically,the inclusion of tannins in FA 70%-TA slightly increased the modulus of elasticity(14%~8732 kg/cm^(2))and the modulus of rupture(9%~40.9 kg/cm^(2)).Furthermore,the tannin addition imparted a darker color to the modified wood,enhancing its aesthetic appeal.This study highlights the potential of tannin-modified furfurylation to advance wood modification technology,combining improved performance with environmental benefits.展开更多
基金Funded by National Key R&D Program of China(No.2021YFB3802300)the National Natural Science Foundation of China(No.52171045)the Joint Fund(No.8091B022108)。
文摘The mechanical and thermodynamic properties of W-Ti alloys(including W_(15)Ti_(1),W_(14)Ti_(2),W_(12)Ti_(4) and W_(8)Ti_(8) alloys)were investigated by the first-principles approach based on density functional theory.The results indicate that W-Ti alloys except W_(8)Ti_(8) are thermodynamically stable.The modulus and hardness of W-Ti alloys are smaller than those of pure tungsten and gradually decrease with increasing Ti concentration.However,their B/G ratios and Poisson's ratios exceed those of pure tungsten,suggesting that the introduction of Ti decreases the mechanical strength while enhancing the ductility of W-Ti alloys.The thermal expansion coefficients for W-Ti alloys all surpass those of pure tungsten,indicating that the introduction of titanium exacerbates the thermal expansion behavior of W-Ti alloys.Nevertheless,elevated pressure has the capacity to suppress the thermal expansion tendencies in titanium-doped tungsten alloys.This study offers theoretical insights for the design of nuclear materials by exploring the mechanical and thermodynamic properties of W-Ti alloys.
文摘In this paper,the effect of sodium laurate(SL)on the properties of sodium lauroyl glutamate(SLG),such as surface activity,foam,wetting,emulsification,and resistance to hard water,has been systematically investigated.The results showed that the critical micelle concentration(cmc)of SLG was 0.30 mmol/L,and the surface tension at the cmc(γcmc)was 34.95 mN/m.With the increase of SL content,the efficiency of SLG solution in reducing the surface tension was decreased.When the SL content was increased,there was no significant change in the foaming ability and foam stability of SLG solutions.The increase of SL content improved both the emulsification and wettability of SLG,but reduced its water resistance.
基金Funded by the Key R&D Projects of Shanxi Province(No.201903D321113)the Shanxi Provincial Natural Science Foundation(No.202303021212359)the General Research Projects of Taiyuan University(No.23TYYB07)。
文摘Carbon fibre,steel fibre and graphite were used as conductive fillers to prepare cementitious materials with excellent electrothermal properties.The electrically conductive cementitious materials with different volume dosages were analysed through compressive and flexural strength,electrochemical impedance spectroscopy and temperature rise tests.An equivalent circuit model was established to study the electrically conductive heat generation mechanism in the electrically conductive cementitious composites.The results indicate that the mechanical properties of cementitious composite materials with a ternary conductive phase are better than those of pristine cementitious materials because the fibrous filler improves their mechanical properties.However,the incorporation of graphite in the material reduces its strength.Introducing fibrous and point-like conductive phase materials into the cementitious material enhances the overall conductive pathway and considerably reduces the electrical resistance of the cementitious material,enhancing its conductive properties.The volume ratios of carbon fibre,steel fibre and graphite that achieve an optimal complex doping in the cementitious material were 0.35%,0.6%and 6%,respectively.This was determined using the mutation point of each circuit element parameter as the percolation threshold.In addition,at a certain safety voltage,there is a uniform change between the internal and surface temperatures of the conductive cementitious material,and the heating effect in this materialis is considerably better than that in the pristine cementitious material.
基金financial support of this work by the National Natural Science Foundation of China(Nos.22378332,52003219)the Open Fund of Zhejiang Key Laboratory of Flexible Electronics(No.2022FE008)+1 种基金the Natural Science Foundation of Ningbo(NO.2022J058)Ministry of Industry and Information Technology high quality development project(TC220A04A-206).
文摘Although poly(lactic acid)(PLA)is a good environmentally-friendly bio-degradable polymer which is used to substitute traditional petrochemical-based polymer packaging films,the barrier properties of PLA films are still insufficient for high-barrier packaging applications.In this study,oxygen scavenger hydroxyl-terminated polybutadiene(HTPB)and cobalt salt catalyst were incorporated into the PLA/poly(butylene adipate-co-terephthalate)(PLA/PBAT),followed by melting extrusion and three-layer co-extrusion blown film process to prepare the composite films.The oxygen permeability coefficient of the composite film combined with 6 wt%oxygen scavenger and 0.4 wt%catalyst was decreased significantly from 377.00 cc·mil·m^(-2)·day^(-1)·0.1 MPa^(-1) to 0.98 cc·mil·m^(-2)·day^(-1)·0.1 MPa^(-1),showing a remarkable enhancement of 384.69 times compared with the PLA/PBAT composite film.Meanwhile,the degradation behavior of the composite film was also accelerated,exhibiting a mass loss of nearly 60%of the original mass after seven days of degradation in an alkaline environment,whereas PLA/PBAT composite film only showed a mass loss of 32%.This work has successfully prepared PLA/PBAT composite films with simultaneously improved oxygen barrier property and degradation behavior,which has great potential for high-demanding green chemistry packaging industries,including food,agricultural,and military packaging.
基金Funded by the National Natural Science Foundation of China(Nos.U1934206,52108260)China Academy of Railway Sciences Fund(No.2021YJ078)+1 种基金Railway Engineering Construction Standard Project(No.2023-BZWW-006)New Cornerstone Science Foundation through the XPLORER PRIZE。
文摘In order to achieve the large-scale application of manufactured sand in railway high-strength concrete structure,a series of high-strength manufactured sand concrete(HMC)are prepared by taking the manufactured sand lithology(tuff,limestone,basalt,granite),stone powder content(0,5%,10%,15%)and concrete strength grade(C60,C80,C100)as variables.The evolution of mechanical properties of HMC and the correlation between cubic compressive strength and other mechanical properties are studied.Compared to river sand,manufactured sand enhances the cubic compressive strength,axial compressive strength and elastic modulus of concrete,while its potential microcracks weaken the flexural strength and splitting tensile strength of concrete.Stone powder content displays both positive and negative effects on mechanical properties of HMC,and the stone powder content is suggested to be less than 10%.The empirical formulas between cubic compressive strength and other mechanical properties are proposed.
文摘The microstructures and thermodynamic properties of mixed systems comprising pyridinium ionic liquid[HPy][BF_(4)]and acetonitrile at different mole fractions were studied using molecular dynamics simulation in this work.The following properties were determined:density,self-diffusion coefficient,excess molar volume,and radial distribution function.The results show that with an increase in the mole fraction of[HPy][BF_(4)],the self-diffusion coefficient decreases.Additionally,the excess molar volume initially decreases,reaches a minimum,and then increases.The rules of radial distribution functions(RDFs)of characteristic atoms are different.With increasing the mole fraction of[HPy][BF_(4)],the first peak of the RDFs of HA1-F decreases,while that of CT6-CT6 rises at first and then decreases.This indicates that the solvent molecules affect the polar and non-polar regions of[HPy][BF_(4)]differently.
文摘Since the discovery of carbon dots(CDs)in 2004,the unique photoluminescence phenomenon of CDs has attracted widespread attention.However,the molecular weight of CDs has not been adequately quantified at present,due to CDs are atomically imprecise and their molecular weight distribution is broad.In this paper,a series of Pluronic-modified CDs were prepared and the structure of the CDs was briefly analyzed.Subsequently,a molecular weight measurement method based on colligative properties was developed,and the correction coefficient in the algorithm was briefly analyzed.The calculated molecular weight was applied to the determination of surface adsorption capacity.This work provided a method for averaging the molecular weight of atomically imprecise particulate materials,which is expected to provide new opportunities in related fields.
文摘Observational data of ball lightning often contradict each other, so it was sometimes proposed to build a theory of ball lightning based on only a small number of statistically reliable observations. Work on this principle did not bring results. The correct approach to creating the theory of ball lightning should be the desire to explain all of its properties, even those that are rare. In the database of ball lightning observations, the most valuable are the cases when it left traces available for quantitative analysis, or was filmed by video cameras. Ball lightning is a material body consisting of a shell and a multi-element core. Cases of water heating made it possible to determine energy density of ball lightning, which turned out to be higher than 1010 J/m3. A study of results of ball lightning explosion, as well as its effect on snow, made it possible to assume that it is capable of generating radiation with a wavelength of about 10 cm, the power of which can be greater than 120 kW. Ball lightning has an electric charge of 10−3 - 10−1 C. The presence of an electric charge explains the complex nature of its movement in atmosphere. Ball lightning is formed under the action of magnetic field pulse and ultraviolet radiation of linear lightning channel. A model of ball lightning in the form of a core of charged “dynamic capacitors” and a shell of polarized water molecules is considered. It is shown that this shell is capable of withstanding the force of Coulomb repulsion of the core charges and the pressure caused by the movement of charge carriers. The glow of ball lightning core occurs due to orbital motion of electrons at a speed close to light speed. The intensity of the glow is determined by the degree of uniformity of electrons arrangement along the orbit.
基金supported by the special fund of Jiangsu Province for the transformation of scientific and technological achievements(BA2021062)Jiangsu agricultural science and technology independent innovation fund(CX(22)2007)。
文摘Edible mushroom proteins are the promising ones with the advantages of complete essential amino acid profile and multiple functional activities.To reinforce their applications in functional food development,this study comprehensively evaluated the physicochemical and functional properties of protein isolates from 5 mushroom species,i.e.,Pleurotus eryngii(PEP),Pleurotus ostreatus(POP),Lentinula edodes(LEP),Flammulina velutipes(FVP)and Hypsizygus marmoreus(HMP).Results showed that PEP,LEP,FVP,POP and HMP exhibited better protein solubility(PS),water holding capacity(WHC),emulsification activity index(EAI),and foaming capacity(FC)than those of soybean protein and pea protein isolates(PPI).PEP(51.95%)and POP(49.15%)had a higher amount ofβ-sheet structure.Principal component analysis and correlation analysis showed that the seven proteins could be divided into 3 clusters,and WHC,EAI and FC were significantly positively correlated with PS andβ-sheet.The least gelation concentration of PEP(16%)and FVP(16%)at p H 6.0 and 7.0 was similar to PPI,and PEP showed better hardness,springiness and rheological properties than other proteins gels.Overall,our study showed that 5 edible mushroom proteins possessed excellent functionalities(except for gelling capacity),which provided novel insights on unexploited sources of mushroom proteins used as protein-based foods in the food industry.
基金financially supported by the National Natural Science Foundation of China(Nos.52174092,51904290,and 52374147)the Natural Science Foundation of Jiangsu Province,China(No.BK20220157)+2 种基金the Fundamental Research Funds for the Central Universities,China(No.2022YCPY0202)the National Key Research and Development Program of China(No.2023YFC3804204)the Major Program of Xinjiang Uygur Autonomous Region S cience and Technology(No.2023A01002)。
文摘The mechanical behavior of cemented gangue backfill materials(CGBMs)is closely related to particle size distribution(PSD)of aggregates and properties of cementitious materials.Consequently,the true triaxial compression tests,CT scanning,SEM,and EDS tests were conducted on cemented gangue backfill samples(CGBSs)with various carbon nanotube concentrations(P_(CNT))that satisfied fractal theory for the PSD of aggregates.The mechanical properties,energy dissipations,and failure mechanisms of the CGBSs under true triaxial compression were systematically analyzed.The results indicate that appropriate carbon nanotubes(CNTs)effectively enhance the mechanical properties and energy dissipations of CGBSs through micropore filling and microcrack bridging,and the optimal effect appears at P_(CNT)of 0.08wt%.Taking PSD fractal dimension(D)of 2.500 as an example,compared to that of CGBS without CNT,the peak strength(σ_(p)),axial peak strain(ε_(1,p)),elastic strain energy(Ue),and dissipated energy(U_(d))increased by 12.76%,29.60%,19.05%,and90.39%,respectively.However,excessive CNTs can reduce the mechanical properties of CGBSs due to CNT agglomeration,manifesting a decrease inρ_(p),ε_(1,p),and the volumetric strain increment(Δε_(v))when P_(CNT)increases from 0.08wt%to 0.12wt%.Moreover,the addition of CNTs improved the integrity of CGBS after macroscopic failure,and crack extension in CGBSs appeared in two modes:detour and pass through the aggregates.Theσ_(p)and U_(d)firstly increase and then decrease with increasing D,and porosity shows the opposite trend.Theε_(1,p)andΔε_(v)are negatively correlated with D,and CGBS with D=2.150 has the maximum deformation parameters(ε_(1,p)=0.05079,Δε_(v)=0.01990)due to the frictional slip effect caused by coarse aggregates.With increasing D,the failure modes of CGBSs are sequentially manifested as oblique shear failure,"Y-shaped"shear failure,and conjugate shear failure.
基金supported by the National Key R&D Program of China(2021YFD2100400,2023YFE0104900)Xinjiang Agriculture Research System-Oil Crop Research System,China(XJARS-05)+3 种基金Taishan Industrial Experts Programme,China(tscx202306075)the Scientific and Technological Assistance Projects to Developing Countries,China(KY202201003)the Agricultural Science and Technology Innovation Program,Institute of Food Science and Technology,Chinese Academy of Agricultural Sciences(CAAS-ASTIP-2024-IFST)The authors are grateful for the financial support from the Arawana Charity Foundation,China.
文摘Peanut varieties are diverse globally,with their characters and nutrition determining the product quality.However,the comparative analysis and statistical analysis of key quality indicators for peanut kernels across the world remains relatively limited,impeding the comprehensive evaluation of peanut quality and hindering the industry development on a global scale.This study aimed to compare and analyze the apparent morphology,microstructure,single-cell structure,engineering and mechanical properties,as well as major nutrient contents of peanut kernels from 10 different cultivars representing major peanut-producing countries.The surface and cross-section microstructure of the peanut kernels exhibited a dense“blocky”appearance with a distinct cellular structure.The lipid droplets were predominantly spherical with a regular distribution within the cells.The single-cell structure of the kernels from these 10 peanut cultivars demonstrated varying morphologies and dimensions,which exhibited correlations with their mechanical and engineering properties.Furthermore,the mass loss versus temperature profiles of the peanut kernels revealed five distinct stages,corresponding to moisture loss,volatile loss,protein denaturation,and the degradation of various biomacromolecules.Variations were also observed in the lipid,protein,and sucrose contents,texture,bulk density,true density,porosity,geometric mean diameter,and sphericity among the diferent peanut varieties.This study establishes relationships and correlations among microstructure,engineering properties,and nutritional composition of commonly grown peanut varieties in major peanut-processing countries.The findings provide valuable insights into peanut quality evaluation,empowering the peanut industry to enhance their processing and product development efforts.
基金the Puncak RM for the project under the grant 6733204-13069 to carry out the experiments。
文摘Graphene nanoplatelets(GNPs)have attracted tremendous interest due to their unique properties and bonding capabilities.This study focuses on the effect of GNP dispersion on the mechanical,thermal,and morphological behavior of GNP/epoxy nanocomposites.This study aims to understand how the dispersion of GNPs affects the properties of epoxy nanocomposite and to identify the best dispersion approach for improving mechanical performance.A solvent mixing technique that includes mechanical stirring and ultrasonication was used for producing the nanocomposites.Fourier transform infrared spectroscopy was used to investigate the interaction between GNPs and the epoxy matrix.The measurements of density and moisture content were used to confirm that GNPs were successfully incorporated into the nanocomposite.The findings showed that GNPs are successfully dispersed in the epoxy matrix by combining mechanical stirring and ultrasonication in a single step,producing well-dispersed nanocomposites with improved mechanical properties.Particularly,the nanocomposites at a low GNP loading of 0.1 wt%,demonstrate superior mechanical strength,as shown by increased tensile properties,including improved Young's modulus(1.86 GPa),strength(57.31 MPa),and elongation at break(4.98).The nanocomposite with 0.25 wt%GNP loading performs better,according to the viscoelastic analysis and flexural properties(113.18 MPa).Except for the nanocomposite with a 0.5 wt%GNP loading,which has a higher thermal breakdown temperature,the thermal characteristics do not significantly alter.The effective dispersion of GNPs in the epoxy matrix and low agglomeration is confirmed by the morphological characterization.The findings help with filler selection and identifying the best dispersion approach,which improves mechanical performance.The effective integration of GNPs and their interaction with the epoxy matrix provides the doorway for additional investigation and the development of sophisticated nanocomposites.In fields like aerospace,automotive,and electronics where higher mechanical performance and functionality are required,GNPs'improved mechanical properties and successful dispersion present exciting potential.
基金Project(2019YFC1803601)supported by the National Key Research and Development Program of ChinaProject(52274182)supported by the National Natural Science Foundation of China+1 种基金Project(2021zzts0274)supported by the Fundamental Research Funds for the Central Universities,ChinaProject(CX20210295)supported by the Postgraduate Scientific Research Innovation Project of Hunan Province,China。
文摘Soil cement bentonite(SCB)is a common material for constructing vertical cutoff walls to prevent groundwater migration at contaminated industrial sites.However,site contaminants can degrade the durability of the cutoff wall.To enhance its performance,this study developed a silica fume-SCB(SSCB).The macroscopic and microscopic properties of SSCB were assessed by unconfined compressive strength test,variable head permeability test,X-ray diffraction(XRD),scanning electron microscopy(SEM)and nuclear magnetic resonance(NMR)spectroscopy.The correlation between its multi-scale properties was analyzed based on pore characteristics.The results indicate that increasing the silica fume substitution ratio improved SSCB strength,especially in the middle and late curing stages.Moreover,increasing the substitution ratio decreased SSCB permeability coefficient,with a more pronounced effect in earlier curing stages.Silica fume addition also refined SSCB pore structure and reduced its porosity.The fractal dimension was used to quantify SSCB pore structure complexity.Increasing silica fume content reduced small pore fractal dimension in SSCB.Concurrently,SSCB strength increased and SSCB permeability coefficient decreased.The findings of this research will demonstrate the great potential of SSCB backfill for practical applications.
基金The Major Science and Technology Project of Nan⁃jing(No.202209012)the Postgraduate Research and Practice Innova⁃tion Program of Jiangsu Province(No.KYCX22⁃0277).
文摘Polyethylene glycol(PEG)with different chains was used to modify epoxy asphalt.Molecular models of PEG⁃modified epoxy asphalt were developed using molecu⁃lar simulations(MS).The thermodynamic and mechanical properties of PEG⁃modified epoxy asphalt were analyzed,and its toughening mechanisms were explored.A method based on the Dijkstra algorithm was proposed to evaluate ep⁃oxy asphalt crosslinked networks.The results show that the introduction of PEG chains into epoxy asphalt can lower the glass transition temperature and enhance its toughness be⁃cause of the extended length of the PEG chains,which can in⁃crease the free volume and improve the mobility of the epoxy resin in the epoxy asphalt.The crosslinked network quantita⁃tive evaluation method based on the Dijkstra algorithm can ef⁃fectively evaluate the distribution of epoxy asphalt crosslink⁃ing bonds,providing further explanation of the toughening mechanism of PEG⁃modified epoxy asphalt.The feasibility of designing and screening epoxy asphalt materials by MS is verified,and a guide for toughening mechanism research of epoxy asphalt at the molecular level is provided.
文摘This study focuses on the thermophysical characterizations of composite materials made from polypropylene reinforced with residues and fibers from Borassus wood from Chad. These properties are experimentally determined at different temperatures using the hot wire method of the “FP2C” machine, where the hot wire probe is inserted between two specimens. The values of the thermal conductivity in powdered Borassus wood range from 0.170 W/mK to 0.182 W/mK for female wood (FNTF) and from 0.169 W/mK to 0.173 W/mK for male wood. For the female and male fibers, the thermal conductivity values range from 0.137 W/mK to 0.157 W/mK for the female and from 0.138 W/mK to 0.168 W/mK for the male. The thermal effusivity of the residues and fibers of Borassus wood varies from: 509.6 Ws1/2/m2K to 543 Ws1/2/m2K for the powder of female wood and from 524.6 Ws1/2/m2K to 547 Ws1/2/m2K for the powder of male wood. For the fibers of Borassus wood, the values range from 410.6 Ws1/2/m2K to 523.6 Ws1/2/m2K for the female wood fibers and from 420.3 Ws1/2/m2K to 480.3 Ws1/2/m2K for the male wood fibers. These results are important for the applications of Borassus wood residues and fibers in construction works regarding the thermal insulation of habitats.
文摘This study investigates the surface properties of the dissimilar AA7075/Mg-WE43 joints wherein the effect of positioning the AA7075 on the advancing or retreating sides during friction stir welding(FSW)was scrutinized.The EBSD analysis revealed that the average grain size reduced from 4.11±0.7μm to 2.04±0.9μm when AA7075 was shifted from advancing to retreating side.The results showed that positioning AA7075 on the retreating side significantly reduced the wear rate from 0.41 mm^(3)/Nm to 0.27 mm^(3)/Nm and mitigates the problem of brittle intermetallic compound(IMC)formation,consequently reducing the average microhardness.Corrosion resistance improved from 77.59 mpy to 56.299 mpy.The higher grain refinement improved wear resistance due to higher grain boundary density and greater chances of formation of protective oxide films.The current work thus enhances the practical applicability of AA7075/Mg-WE43 welds for lightweighting of automotive structures.
基金financially supported by the Grant GO995/48-1 to S.N.G.from the National Priority Program SPP2416″Code-Chi-Chitin,chitosan and chitooligosaccharides and their interaction with proteins of the extracellular matrix and cellular signaling”of the German Science Foundation(DFG).
文摘Scorpions are distributed almost all over the world and inhabit rainforests,deserts,mountains,and littoral zones.Their multifunctional chelae play a key role in their biology.The chela is the pincer that has originated from the last two segments of the pedipalp.Many previous studies have focused on the morphology of the chela and the overall pincer force.The knowledge about the material properties of scorpion chelae remains rather poor.In particular,little is known about the spines located on the grasping edge of the chela.In this study,we use a combination of nanoindentation,micro-computer tomography,confocal laser scanning microscopy,scanning electron microscopy and energy-dispersive X-ray elemental analysis,to examine the mechanical properties,relative density,sclerotization level,microstructure and biomineralization of both the regular cuticle and the spine cuticle of the chela in the scorpion Androctonus bicolor.Our results show that the mechanical property values of the spine cuticle are significantly higher than those of the regular cuticle.This can reduce the risk of damage to the chela,increase the chance of indentation into the prey tissue and is very likely to result from both higher sclerotization level and biomineralization due to the accumulation of zinc.The specialized microstructure of the cuticle could contribute to the enhancement of the stiffness,strength and toughness of the chela.This study aids in better understanding the material structure,composition and properties of the scorpion chela cuticle.
基金supported by the National Key Research and Development Program of China(No.2022YFC3701000)the National Natural Science Foundation of China(Nos.42130606 and 41931287)+1 种基金the Beijing National Laboratory for Molecular Sciences(BNLMS-CXXM-202011)the Youth Innovation Promotion Association of the Chinese Academy of Sciences(No.Y2021013).
文摘With the rapid development of the world economy,complex air pollution has increasingly become a serious threat;for example,with haze events occurring frequently in various regions of the globe.Recent evidence has indicated that secondary aerosols play an important role in haze formation,and that heterogeneous processes are among the main forces driving their explosive growth.In this regard,this paper reviews recent advances in the understanding of the impact of heterogeneous processes on haze chemistry,including the impact on NO_(2)chemistry,marine aerosols,and the hygroscopicity and optical properties of atmospheric aerosols.It is distinguished from past reviews on this topic by focusing mainly on new insights from the past five years.We summarize the main findings of the impacts of heterogeneous processes on NO_(2)chemistry,marine aerosols,and the physicochemical properties of atmospheric aerosols,and propose several future research directions.
基金Natural Science Foundation of Ningxia,China(No.2023AAC03284)Fundamental Research Funds for the Central Universities Research Project of North Minzu University,China(No.2022XYZCL04)+1 种基金Project of Key Laboratory of Powders and Advanced CeramicsCo-founded by Ningxia and the State Ethnic Affairs Commission,China(No.2103)。
文摘Cr_(2)O_(3)was used as grain inhibitor in Ti(C,N)-based cermets with vacuum sintering.The microstructure and mechanical and tribological properties of cermets with Cr_(2)O_(3)and Cr_(3)C_(2)were investigated.The results show that adding Cr_(2)O_(3)promotes a gray core/gray rim structure formation and finer size of Ti(C,N)hard phase.Compared with the cermet with an equal Cr_(3)C_(2)addition,the cermet with 0.6 wt.%Cr_(2)O_(3)exhibits 16.5%higher transverse rupture strength.This enhancement is likely due to the smaller lattice misfit at the core/rim interface and more uniform Cr distribution in the binder.Additionally,at room temperature(25℃)and 800℃,Cr_(2)O_(3)-containing cermets demonstrate lower coefficients of friction and volume wear ratios than Cr_(3)C_(2)-containing cermets,with the wear ratio difference reaching an order of magnitude.Scanning electron microscopy and X-ray photoelectron spectroscopy results further confirm more oxidation wear in Cr_(2)O_(3)-containing cermets than in Cr_(3)C_(2)-containing cermets.
基金funded by the Directorate General of Higher Education,Research,and Technology,Ministry of Education,Culture,Research,and Technology,Indonesia,which sponsored the research grant via the National Competitive Basic Research Scheme,No.027/E5/PG.02.00.PL/2024facilitated by IPB University(Bogor Agricultural University)through Research Contract No.22055/IT3.D10/PT.01.03/P/B/2024+1 种基金funded by Research Organization for Nanotechnology and Materials No.3/III.10/HK/2023National Research and Innovation Agency(BRIN),Indonesia.
文摘Furfurylation,a renowned chemical modification technique,uses furfuryl alcohol to enhance the properties of wood.This technology can be further refined by incorporating renewable tannins,which promote cross-linking with furfuryl alcohol.This study investigates the effects of furfurylation and tannin-modified furfurylation on the physical and mechanical properties of tropical Gmelina wood(Gmelina arborea Roxb.).Experiments involved impregnating Gmelina wood with aqueous solutions of furfuryl alcohol(FA)at 40%and 70%concentrations,as well as FA-tannin combinations(FA 40%-TA and FA 70%-TA),followed by polymerization at 103℃.The results demonstrated that both FA and FA-tannin treatments significantly improved the wood’s physical and mechanical properties.Notably,FA-tannin treatments achieved anti-swelling efficiency comparable to FA alone.However,the addition of tannins(FA 70%-TA)enhanced leaching resistance by up to 47%,contributing to a more environmentally sustainable modification process.Mechanically,the inclusion of tannins in FA 70%-TA slightly increased the modulus of elasticity(14%~8732 kg/cm^(2))and the modulus of rupture(9%~40.9 kg/cm^(2)).Furthermore,the tannin addition imparted a darker color to the modified wood,enhancing its aesthetic appeal.This study highlights the potential of tannin-modified furfurylation to advance wood modification technology,combining improved performance with environmental benefits.
