The functional properties of glasses are governed by their formation history and the complex relaxation processes they undergo.However,under extreme conditions,glass behaviors are still elusive.In this study,we employ...The functional properties of glasses are governed by their formation history and the complex relaxation processes they undergo.However,under extreme conditions,glass behaviors are still elusive.In this study,we employ simulations with varied protocols to evaluate the effectiveness of different descriptors in predicting mechanical properties across both low-and high-pressure regimes.Our findings demonstrate that conventional structural and configurational descriptors fail to correlate with the mechanical response following pressure release,whereas the activation energy descriptor exhibits robust linearity with shear modulus after correcting for pressure effects.Notably,the soft mode parameter emerges as an ideal and computationally efficient alternative for capturing this mechanical behavior.These findings provide critical insights into the influence of pressure on glassy properties,integrating the distinct features of compressed glasses into a unified theoretical framework.展开更多
Traditional selection of combustion catalysis is time-consuming and labor-intensive.Theoretical calculation is expected to resolve this problem.The adsorption energy of HMX and O atoms on 13 metal oxides was calculate...Traditional selection of combustion catalysis is time-consuming and labor-intensive.Theoretical calculation is expected to resolve this problem.The adsorption energy of HMX and O atoms on 13 metal oxides was calculated using DMol3,since HMX and O are key substances in decomposition process.And the relationship between the adsorption energy of HMX,O on metal oxides(TiO_(2),Al_(2)O_(3),PbO,CuO,Fe_(2)O_(3),Co_(3)O_(4),Bi_(2)O_(3),NiO)and experimental T30 values(time required for the decomposition depth of HMX to reach 30%)was depicted as volcano plot.Thus,the T30 values of other metal oxides was predicted based on their adsorption energy on volcano plot and validated by previous experimental data.Further,the adsorption energy of HMX on ZrO_(2)and MnO_(2)was predicted based on the linear relationship between surface energy and adsorption energy,and T30 values were estimated based on volcano plot.The apparent activation energy data of HMX/MgO,HMX/SnO_(2),HMX/ZrO_(2),and HMX/MnO_(2)obtained from DSC experiments are basically consistent with our predicted T30 values,indicating that it is feasible to predict the catalytic activity based on the adsorption calculation,and it is expected that these simple structural properties can predict adsorption energy to reduce the large quantities of computation and experiment cost.展开更多
Styrene-butadiene-styrene(SBS)modified asphalt(SA)has long found effective applications in road construction materials.When combined with fillers,SBS-modified asphalt has demonstrated promising resistance to fatigue c...Styrene-butadiene-styrene(SBS)modified asphalt(SA)has long found effective applications in road construction materials.When combined with fillers,SBS-modified asphalt has demonstrated promising resistance to fatigue cracking caused by temperature fluctuations and aging.In this study,molybdenum disulfide(MoS_(2))and polyphosphoric acid(PPA)were ground in naphthenic oil(NO)and subjected to mechanical activation to create PPAmodified MoS_(2),referred to as OMS-PPA.By blending various ratios of OMS-PPA with SBS-modified asphalt,composite-modified asphalts were successfully developed to enhance their overall properties.To assess the mechanical characteristics and stability of these modified asphalts,various methods were employed,including penetration factor,flow activation energy,fluorescence microscopy,and dynamic shear rheology.Additionally,the short-term aging performance was evaluated using Fourier transform infrared(FTIR)spectroscopy and nanoindentation tests.The results revealed a 3.7%decrease in the penetration-temperature coefficient for SAOMS compared to SA,while 1-SA-OMS-PPA showed an even greater reduction of 7.1%.Furthermore,after short-term aging,carboxyl group generation in SA increased by 5.93%,while SA-OMS exhibited a smaller rise of 1.36%,and 1-SA-OMS-PPA saw an increase of just 0.93%.The study also highlighted significant improvements in the hardness of these materials.The hardness change ratio for SA-OMS decreased by 43.08%,while the ratio for 1-SA-OMS-PPA saw a notable reduction of 65.16% compared to unmodified SA.These findings suggest that OMS-PPA contributed to improvements in temperature sensitivity,particle dispersibility,and resistance to shortterm aging in asphalts.The results hold significant promise for the future development of advanced asphalt-based materials with potential high-value applications in flexible pavements for highways.展开更多
Hybrid energy storage can enhance the economic performance and reliability of energy systems in industrial parks,while lowering the industrial parks’carbon emissions and accommodating diverse load demands from users....Hybrid energy storage can enhance the economic performance and reliability of energy systems in industrial parks,while lowering the industrial parks’carbon emissions and accommodating diverse load demands from users.However,most optimization research on hybrid energy storage has adopted rulebased passive-control principles,failing to fully leverage the advantages of active energy storage.To address this gap in the literature,this study develops a detailed model for an industrial park energy system with hybrid energy storage(IPES-HES),taking into account the operational characteristics of energy devices such as lithium batteries and thermal storage tanks.An active operation strategy for hybrid energy storage is proposed that uses decision variables based on hourly power outputs from the energy storage of the subsequent day.An optimization configuration model for an IPES-HES is formulated with the goals of reducing costs and lowering carbon emissions and is solved using the non-dominated sorting genetic algorithm Ⅱ(NSGA-Ⅱ).A method using the improved NSGA-Ⅱ is developed for day-ahead nonlinear scheduling,based on configuration optimization.The research findings indicate that the system energy bill and the peak power of the IPES-HES under the optimization-based operational strategy are reduced by 181.4 USD(5.5%)and 1600.3 kW(43.7%),respectively,compared with an operation strategy based on proportional electricity storage on a typical summer day.Overall,the day-ahead nonlinear optimal scheduling method developed in this study offers guidance to fully harness the advantages of active energy storage.展开更多
In order to evaluate the spontaneous combustion hazard of sulfide concentrates in storage, three different kinds of sulfide concentrates （sulfur-rich sulfide concentrate, iron sulfide concentrate and copper sulfide c...In order to evaluate the spontaneous combustion hazard of sulfide concentrates in storage, three different kinds of sulfide concentrates （sulfur-rich sulfide concentrate, iron sulfide concentrate and copper sulfide concentrate） were obtained from a storage yard in Dongguashan Copper Mine, China. The reaction processes at different heating rates of 5, 10, 15, 20, and 25 ℃/min in air flow from ambient temperature to 1 000 ℃ were studied by TG-DTG-DSC analysis. By the peak temperatures of DTG curves, the whole reaction process for each sample was divided into different stages, and the corresponding apparent activation energies were calculated by the Ozawa-Flynn-Wall method. It is found that the reaction process of each sample is considerably complex; the apparent activation energy values change from 36 to 160 kJ/mol in different temperature ranges; sulfur-rich sulfide and iron sulfide concentrates have lower apparent activation energy than copper sulfide concentrate below 150 ℃; so they are more inclined to cause spontaneous combustion at ambient temperature.展开更多
To investigate the flow behavior of 2219 Al alloy during warm deformation,the thermal compression test was conducted in the temperature range of 483-573 K and the strain rate range of 0.001-5 s^(-1) on a Gleeble-3500 ...To investigate the flow behavior of 2219 Al alloy during warm deformation,the thermal compression test was conducted in the temperature range of 483-573 K and the strain rate range of 0.001-5 s^(-1) on a Gleeble-3500 thermomechanical simulation unit.The true stress-true strain curves obtained showed that the flow stress increased with the decrease in temperature and/or the increase in strain rate and the softening mechanism primarily proceeded via dynamic recovery.The modification on the conventional Arrhenius-type constitutive model approach was made,the material variables and activation energy were determined to be dependent on the deformation parameters.The modified flow stresses were found to be in close agreement with the experimental values.Furthermore,the activation energy obtained under different deformation conditions showed that it decreased with the rise in temperature and/or strain rate,and was also affected by the coupled effect of strain and strain rate.展开更多
The hot deformation behaviors of Ni18 Cr9 Co9 Fe5 Nb3 Mo superalloy were explored in the formation temperature range free ofγ’phase with various strain rates applied.The hot deformation behaviors are initially model...The hot deformation behaviors of Ni18 Cr9 Co9 Fe5 Nb3 Mo superalloy were explored in the formation temperature range free ofγ’phase with various strain rates applied.The hot deformation behaviors are initially modeled with Arrhenius equation which gives an average activation energy of 581.1 kJ mol^(-1).A modified Arrhenius approach,including the updated Zener-Hollomon parameter is proposed to consider the change of activation ene rgy under different deformation conditions which turns out a relatively accurate computation for activation energy of hot deformation,i.e.,the standard variance for modified model calculated in the covered deformation condition is just 35.4%of that for Arrhenius equation.The modified model also proposes a map for activation ene rgy which ranges from 571.5-589.0 kJ mol^(-1)for various deformation conditions.Microstructural features of the representative superalloy specimens were characterized by electron backscattered diffraction(EBSD)techniques in order to clarify the influence of activation energy on the microstructural formation.It is found that the Ni-based superalloy samples with higher activation energy are promoted by the degree of dynamic recrystallization which suggests that the rise in activation energy gives either a better recrystallization rate or finer grains.展开更多
Synthesis and use of the iron compounds supported on granular activated carbon （ICs/GAC） have shown significant environmental implications for perchlorate （ClO4^- ） removal. ICs/GAC was synthesized via hydrolyzing...Synthesis and use of the iron compounds supported on granular activated carbon （ICs/GAC） have shown significant environmental implications for perchlorate （ClO4^- ） removal. ICs/GAC was synthesized via hydrolyzing FeSO 4 ·7H2O on GAC, reduced by NaBH 4 solution in polyethylene glycol 6000 and ethanol solution, dried in vacuum condition and exposed to air. Synthesized ICs/GAC was characterized using transmission electron micrograph （TEM）, Brunauer-Emmett-Teller, X-ray photoelectron spectroscopy （XPS）. ICs/GAC was determined to be containing a large amount of FeOHSO 4 , Fe2O3 and a small amount of zero-valent iron （ZVI） nanoparticles according to TEM and XPS measurements. Batch static kinetic tests showed that 97% of ClO4^- was removed within 10 hr at 90°C and 86% of ClO4^- was removed within 12 hr at 25°C, at ICs/GAC dosage of 20 g/L. The experimental results also showed that FeOHSO 4 and Fe 2 O 3 nanoparticles have the function of perchlorate adsorption and play important roles in ClO4^- removal. The activation energy （E a ） was determined to be 9.56 kJ/mol.展开更多
The oxidation behaviors of AZ80,AZ8O-0.32 Y and AZ8O-0.38 Nd(wt.%)alloys were researched at 413℃,420℃,427v and 433℃for up to 6 h in air environment via a high precision analytical balance,a laser confocal microscop...The oxidation behaviors of AZ80,AZ8O-0.32 Y and AZ8O-0.38 Nd(wt.%)alloys were researched at 413℃,420℃,427v and 433℃for up to 6 h in air environment via a high precision analytical balance,a laser confocal microscope,differential scanning calorimeter(DSC)analysis,X-ray diffraction(XRD)analysis,scanning electron microscope(SEM)observation,and X-ray photoelectron spectroscopy(XPS)analysis.The results show that the weight gain and oxidation rate of AZ80 are reduced significantly,the initiation form and propagation of cracks in oxide layer are changed.Compact and protective oxide layer forms on alloy surface with Y or Nd addition.And the activation energies of AZ80,AZ80-0.32Y and AZ8O-0.38Nd alloys calculated via Arrhenius equation are 82.556 kJ/mol,177.148kJ/mol and 136.738 kJ/mol,respectively.展开更多
The 4340 steel is extensively utilized in several industries including automotive and aerospace for manufac- turing a large number of structural components. Due to the importance of thermo-mechanical processing in the...The 4340 steel is extensively utilized in several industries including automotive and aerospace for manufac- turing a large number of structural components. Due to the importance of thermo-mechanical processing in the pro- duction of steels, the dynamic recrystallization （DRX） characteristics of 4340 steel were investigated. Namely, hot compression tests on 4340 steel have been performed in a temperature range of 900-- 1200 ℃ and a strain rate range of 0.01--1 s-1 and the strain of up to 0.9. The resulting flow stress curves show the occurrence of dynamic recrys- tallization. The flow stress values decrease with the increase of deformation temperature and the decrease of strain rate. The microstrueture of 4340 steel after deformation has been studied and it is suggested that the evolution of DRX grain structures can be accompanied by considerable migration of grain boundaries. The constitutive equations were developed to model the hot deformation behavior. Finally based on the classical stress-dislocation relations and the kinematics of the dynamic recrystallization; the flow stress constitutive equations for the dynamic recovery period and dynamic reerystallization period were derived for 4340 steel, respectively. The validity of the model was demon- strated by demonstrating the experimental data with the numerical results with reasonable agreement.展开更多
By analyzing previous studies on activation energy of coal oxidation at low temperatures, a theoretical calculation model of apparent activation energy is established. Yield of CO is measured by using the characterist...By analyzing previous studies on activation energy of coal oxidation at low temperatures, a theoretical calculation model of apparent activation energy is established. Yield of CO is measured by using the characteristic detector of coal oxidation at 30-90 ℃. The impact of parameters, such as airflow and particle size, on activation energies is analyzed. Finally, agreement was obtained between activation energies and the dynamic oxygen absorbed in order to test the accuracy of the model. The results show that： 1） a positive exponential relation between concentration of CO and temperature in the process of the experiment is obtained： increases are almost identical and the initial CO is low; 2） the apparent activation energies increase gradually with the sizes of particle at the same airflow, but the gradients increase at a decreasing rate; 3） the apparent activation energies increase linearly with airflow. For the five coal particles, the differences among the energies are relatively high when the airflow was low, but the differences were low when the airflow was high; 4） the optimum sizes of particle, 0.125-0.25 ram, and the optimum volume of airflow, 100 mL/min, are determined from the model; 5） the apparent activation energies decrease with an increase in oxygen absorbed. A negative exponential relation between the two is obtained,展开更多
Thermal maturation and petroleum generation modeling of shales is essential for suc- cessful exploration and exploitation of conventional and unconventional oil and gas plays. For basin- wide unconventional resource p...Thermal maturation and petroleum generation modeling of shales is essential for suc- cessful exploration and exploitation of conventional and unconventional oil and gas plays. For basin- wide unconventional resource plays such modeling, when well calibrated with direct maturity meas- urements from wells, can characterize and locate production sweet spots for oil, wet gas and dry gas. The transformation of kerogen to petroleum is associated with many chemical reactions, but models typically focus on first-order reactions with rates determined by the Arrhenius Equation. A miscon- ception has been perpetuated for many years that accurate thermal maturity modeling of vitrinite re- flectance using the Arrhenius Equation and a single activation energy, to derive a time-temperature index （~TTIARa）, as proposed by Wood （1988）, is flawed. This claim was initially made by Sweeney and Burnham （1990） in promoting their ＂EasyRo＂ method, and repeated by others. This paper dem- onstrates through detailed multi-dimensional burial and thermal modeling and direct comparison of the ~TTIARR and ＂EasyRo＂ methods that this is not the case. The ~TTIA^R method not only provides a very useful and sensitive maturity index, it can reproduce the calculated vitrinite reflectance values derived from models based on multiple activation energies （e.g., ＂EasyRo＂）. Through simple expres- sions the ~TTIAaa method can also provide oil and gas transformation factors that can be flexibly scaled and calibrated to match the oil, wet gas and dry gas generation windows. This is achieved in a more-computationally-efficient, flexible and transparent way by the ~TTIARR method than the ＂EasyRo＂ method. Analysis indicates that the ＂EasyRo＂ method, using twenty activation energies and a constant frequency factor, generates reaction rates and transformation factors that do not realisti- cally model observed kerogen behaviour and transformation factors over geologic time scales.展开更多
This research work explores the effect of hybrid nanoparticles on the flow over a rotating disk by using an activation energy model.Here,we considered molybdenum disulfide and ferro sulfate as nanoparticles suspended ...This research work explores the effect of hybrid nanoparticles on the flow over a rotating disk by using an activation energy model.Here,we considered molybdenum disulfide and ferro sulfate as nanoparticles suspended in base fluid water.The magnetic field is pragmatic normal to the hybrid nanofluid flow direction.The derived nonlinear ordinary differential equations are non-dimensionalized and worked out numerically with the help of Maple software by the RKF-45 method.The scientific results for a non-dimensionalized equation are presented for both nanoparticle and hybrid nanoparticle case.Accoutrements of various predominant restrictions on flow and thermal fields are scanned.Computation estimation for friction factor,local Nusselt number and Sherwood number are also executed.Results reveal that the reduction of the heat transfer rate is greater in hybrid nanoparticles when compared to nanoparticles for increasing values of Eckert Number and the thermal field enhances for the enhanced values of volume fraction.展开更多
Accelerated carbonation experiments about the development of carbonation rates of ordinary Portland cement concrete under different artificial climates were carried out. Six water cement ratios and six climate conditi...Accelerated carbonation experiments about the development of carbonation rates of ordinary Portland cement concrete under different artificial climates were carried out. Six water cement ratios and six climate condition combinations of temperature and relative humidity were used. Results indicate that changes of concrete carbonation rate with environmental temperature agree the Arrhenius law well, which suggests concrete carbonation rate has obvious dependence on temperature. The higher the temperature is, the more quickly the concrete carbonates, and at the same time it is also affected by environmental relative humidity. Thereafter, the apparent activation energy Ea of concrete carbonation reaction was obtained, ranging from 16.8 to 20.6 kJ/mol corresponding 0.35-0.74 water cement ratio, and lower water cement ratio will cause the apparent activation energy increase. Concrete carbonation rates will increase 1.1-1.69 times as temperature increase every 10 ℃ at the temperature range of 10 to 60 ℃.展开更多
Correlations among free radicals, apparent activation energy, and functional groups during lowtemperature oxidation of Jurassic coal in Northern Shaanxi were investigated by examining three coal samples collected from...Correlations among free radicals, apparent activation energy, and functional groups during lowtemperature oxidation of Jurassic coal in Northern Shaanxi were investigated by examining three coal samples collected from the Ningtiaota, Jianxin, and Shigetai coal mines. Free radical concentrations at less than 120 ℃ were investigated by electron spin resonance experiments while the thermogravimetric experiments were conducted to analyze apparent activation energies. In addition, Fourier transform infrared spectroscopy was employed to study the spectrum of functional groups generated in coal. The results indicated that, in decreasing order, the apparent activation energies were Shigetai 〉Jianxin 〉 Ningtiaota, indicating that, from 50 to 120 ℃, the Ningtiaota coal sample most easily absorbed and reacted with oxygen while the most resistant was the Shigetai coal sample. Free radical concentrations and line heights increased with increased temperature, and the line width and Lande factor showed irregular fluctuations. Functional group variations were different among these coals, and the phenol and alcohol-associated OHs, carboxyls, and aromatic ring double bonds might have had a major impact on free radical concentrations. These results were meaningful for better consideration and management of coal oxidation at low temperatures.展开更多
The present exploration is conducted to describe the motion of viscous fluid embedded in squeezed channel under the applied magnetics effects.The processes of heat and mass transport incorporate the temperature-depend...The present exploration is conducted to describe the motion of viscous fluid embedded in squeezed channel under the applied magnetics effects.The processes of heat and mass transport incorporate the temperature-dependent binary chemical reaction with modified Arrhenius theory of activation energy function which is not yet disclosed for squeezing flow mechanism.The flow,heat and mass regime are exposed to be governed via dimensionless,highly non-linear,ordinary differential equations (ODEs) under no-slip walls boundary conditions.A well-tempered analytical convergent procedure is adopted for the solutions of boundary value problem.A detailed study is accounted through graphs in the form of flow velocity field,temperature and fluid concentration distributions for various emerging parameters of enormous interest.Skin-friction,Nusselt and Sherwood numbers have been acquired and disclosed through plots.The results indicate that fluid temperature follows an increasing trend with dominant dimensionless reaction rate σ and activation energy parameter E.However,an increment in σ and E parameters is found to decline in fluid concentration.The current study arises numerous engineering and industrial processes including polymer industry,compression and injection shaping,lubrication system,formation of paper sheets,thin fiber,molding of plastic sheets.In the area of chemical engineering,geothermal engineering,cooling of nuclear reacting,nuclear or chemical system,bimolecular reactions,biochemical process and electrically conducting polymeric flows can be controlled by utilizing magnetic fields.Motivated by such applications,the proposed study has been developed.展开更多
The apparent activation energy of concrete in early age was determined by adiabatic temperature rise test with different initial temperatures. The influence of mineral admixtures such as fly ash, slag and silica fume ...The apparent activation energy of concrete in early age was determined by adiabatic temperature rise test with different initial temperatures. The influence of mineral admixtures such as fly ash, slag and silica fume on the apparent activation energy of concrete was investigated. The equivalent age that expresses the maturity of concrete was calculated to evaluate the cracking risk of concrete in structures. The results reveal that a substitution of 20% fly ash for Portland cement obviously decreases the apparent activation energy of concrete, however, a substitution of 10% silica fume for Portland cement increases the apparent activation. Finite element method analysis of a simulating concrete wall shows that the concrete containing 20% fly ash has the lowest cracking risk.展开更多
The buoyancy driven flow of a second-grade nanofluid in the presence of a binary chemical reaction is analyzed in the context of a model based on the balance equations for mass,species concentration,momentum and energ...The buoyancy driven flow of a second-grade nanofluid in the presence of a binary chemical reaction is analyzed in the context of a model based on the balance equations for mass,species concentration,momentum and energy.The elastic properties of the considered fluid are taken into account.The two-dimensional slip flow of such non-Newtonian fluid over a porous flat material which is stretched vertically upwards is considered.The role played by the activation energy is accounted for through an exponent form modified Arrhenius function added to the Buongiorno model for the nanofluid concentration.The effects of thermal radiation are also examined.A similarity transformations is used to turn the problem based on partial differential equations into a system of ordinary differential equations.The resulting system is solved using a fourth order RK and shooting methods.The velocity profile,temperature profile,concentration profile,local skin friction,local Nusselt number and local Sherwood number are reported for several circumstances.The influence of the chemical reaction on the properties of the concentration and momentum boundary layers is critically discussed.展开更多
Heterogeneous cellular networks(HCNs), by introducing caching capability, has been considered as a promising technique in 5 G era, which can bring contents closer to users to reduce the transmission delay, save scarce...Heterogeneous cellular networks(HCNs), by introducing caching capability, has been considered as a promising technique in 5 G era, which can bring contents closer to users to reduce the transmission delay, save scarce bandwidth resource. Although many works have been done for caching in HCNs, from an energy perspective, there still exists much space to develop a more energy-efficient system when considering the fact that the majority of base stations are under-utilized in the most of the time. Therefore, in this paper, by taking the activation mechanism for the base stations into account, we study a joint caching and activation mechanism design to further improve the energy efficiency, then we formulate the optimization problem as an Integer Linear Programming problem(ILP) to maximize the system energy saving. Due to the enormous computation complexity for finding the optimal solution, we introduced a Quantum-inspired Evolutionary Algorithm(QEA) to iteratively provide the global best solution. Numerical results show that our proposed algorithm presents an excellent performance, which is far better than the strategy of only considering caching without deactivation mechanism in the actual, normal situation. We also provide performance comparison amongour QEA, random sleeping algorithm and greedy algorithm, numerical results illustrate our introduced QEA performs best in accuracy and global optimality.展开更多
Bioconvection research is primarily focused on the augmentation of energy and mass species,which has implications in the processes intensification,mechanical,civil,electronics,and chemical engineering branches.Advance...Bioconvection research is primarily focused on the augmentation of energy and mass species,which has implications in the processes intensification,mechanical,civil,electronics,and chemical engineering branches.Advanced bioconvection technology sectors include cooling systems for electronic devices,building insulation,and geothermal nuclear waste disposal.Hence,the present investigation is mainly discoursing the impact of Marangoni convention Casson nanoliquid flow under gyrotactic microorganisms over the porous sheet.The partial differential equations(PDEs)are re-structured into ordinary differential equations(ODEs)via suitable similar variables.These ODEs are numerically solved with the help of the spectral relaxation method(SRM).The numerical outcomes are illustrated graphically for various parameters over velocity,temperature,concentration,and bioconvection profiles.Three-dimensional(3 D)views of important engineering parameters are illustrated for various parameters.The velocity of the Casson nanoliquid increases with increasing the Marangoni parameter but decreases against higher porosity parameter.The surface drag force enhances for enhancement in the Marangoni number.The rate of mass transmission is higher for reaction rate constraint but diminishes for activation energy parameter.The higher radiative values augment the rate of heat transmission.展开更多
基金supported by the National Natural Science Foundation of China (Grant Nos.T2325004 and 52161160330)the National Natural Science Foundation of China (Grants No.12504233)+2 种基金Advanced MaterialsNational Science and Technology Major Project (Grant No.2024ZD0606900)the Talent Hub for “AI+New Materials” Basic Researchthe Key Research and Development Program of Ningbo (Grant No.2025Z088)。
文摘The functional properties of glasses are governed by their formation history and the complex relaxation processes they undergo.However,under extreme conditions,glass behaviors are still elusive.In this study,we employ simulations with varied protocols to evaluate the effectiveness of different descriptors in predicting mechanical properties across both low-and high-pressure regimes.Our findings demonstrate that conventional structural and configurational descriptors fail to correlate with the mechanical response following pressure release,whereas the activation energy descriptor exhibits robust linearity with shear modulus after correcting for pressure effects.Notably,the soft mode parameter emerges as an ideal and computationally efficient alternative for capturing this mechanical behavior.These findings provide critical insights into the influence of pressure on glassy properties,integrating the distinct features of compressed glasses into a unified theoretical framework.
基金supported by Key Science and Technology Innovation Team of Shaanxi Province(No.2022TD-33)National Natural Science Foundation of China(Grant Nos.21373161,21504067)。
文摘Traditional selection of combustion catalysis is time-consuming and labor-intensive.Theoretical calculation is expected to resolve this problem.The adsorption energy of HMX and O atoms on 13 metal oxides was calculated using DMol3,since HMX and O are key substances in decomposition process.And the relationship between the adsorption energy of HMX,O on metal oxides(TiO_(2),Al_(2)O_(3),PbO,CuO,Fe_(2)O_(3),Co_(3)O_(4),Bi_(2)O_(3),NiO)and experimental T30 values(time required for the decomposition depth of HMX to reach 30%)was depicted as volcano plot.Thus,the T30 values of other metal oxides was predicted based on their adsorption energy on volcano plot and validated by previous experimental data.Further,the adsorption energy of HMX on ZrO_(2)and MnO_(2)was predicted based on the linear relationship between surface energy and adsorption energy,and T30 values were estimated based on volcano plot.The apparent activation energy data of HMX/MgO,HMX/SnO_(2),HMX/ZrO_(2),and HMX/MnO_(2)obtained from DSC experiments are basically consistent with our predicted T30 values,indicating that it is feasible to predict the catalytic activity based on the adsorption calculation,and it is expected that these simple structural properties can predict adsorption energy to reduce the large quantities of computation and experiment cost.
基金financially supported by the Key Research and Development Program of Hubei Province(Nos.2022BCA077 and 2022BCA082).
文摘Styrene-butadiene-styrene(SBS)modified asphalt(SA)has long found effective applications in road construction materials.When combined with fillers,SBS-modified asphalt has demonstrated promising resistance to fatigue cracking caused by temperature fluctuations and aging.In this study,molybdenum disulfide(MoS_(2))and polyphosphoric acid(PPA)were ground in naphthenic oil(NO)and subjected to mechanical activation to create PPAmodified MoS_(2),referred to as OMS-PPA.By blending various ratios of OMS-PPA with SBS-modified asphalt,composite-modified asphalts were successfully developed to enhance their overall properties.To assess the mechanical characteristics and stability of these modified asphalts,various methods were employed,including penetration factor,flow activation energy,fluorescence microscopy,and dynamic shear rheology.Additionally,the short-term aging performance was evaluated using Fourier transform infrared(FTIR)spectroscopy and nanoindentation tests.The results revealed a 3.7%decrease in the penetration-temperature coefficient for SAOMS compared to SA,while 1-SA-OMS-PPA showed an even greater reduction of 7.1%.Furthermore,after short-term aging,carboxyl group generation in SA increased by 5.93%,while SA-OMS exhibited a smaller rise of 1.36%,and 1-SA-OMS-PPA saw an increase of just 0.93%.The study also highlighted significant improvements in the hardness of these materials.The hardness change ratio for SA-OMS decreased by 43.08%,while the ratio for 1-SA-OMS-PPA saw a notable reduction of 65.16% compared to unmodified SA.These findings suggest that OMS-PPA contributed to improvements in temperature sensitivity,particle dispersibility,and resistance to shortterm aging in asphalts.The results hold significant promise for the future development of advanced asphalt-based materials with potential high-value applications in flexible pavements for highways.
基金supported by National Key Research and Development Program of China(2022YFB4201003)the National Natural Science Foundation of China(52278104 and 52108076)the Science and Technology Innovation Program of Hunan Province(2023RC1042).
文摘Hybrid energy storage can enhance the economic performance and reliability of energy systems in industrial parks,while lowering the industrial parks’carbon emissions and accommodating diverse load demands from users.However,most optimization research on hybrid energy storage has adopted rulebased passive-control principles,failing to fully leverage the advantages of active energy storage.To address this gap in the literature,this study develops a detailed model for an industrial park energy system with hybrid energy storage(IPES-HES),taking into account the operational characteristics of energy devices such as lithium batteries and thermal storage tanks.An active operation strategy for hybrid energy storage is proposed that uses decision variables based on hourly power outputs from the energy storage of the subsequent day.An optimization configuration model for an IPES-HES is formulated with the goals of reducing costs and lowering carbon emissions and is solved using the non-dominated sorting genetic algorithm Ⅱ(NSGA-Ⅱ).A method using the improved NSGA-Ⅱ is developed for day-ahead nonlinear scheduling,based on configuration optimization.The research findings indicate that the system energy bill and the peak power of the IPES-HES under the optimization-based operational strategy are reduced by 181.4 USD(5.5%)and 1600.3 kW(43.7%),respectively,compared with an operation strategy based on proportional electricity storage on a typical summer day.Overall,the day-ahead nonlinear optimal scheduling method developed in this study offers guidance to fully harness the advantages of active energy storage.
基金Project (2006BAK04B03) supported by the National Science and Technology Pillar Program during the 11th Five-Year Plan Period of ChinaProject (kjdb200902-7) supported by Doctoral Candidate Innovation Research Support Program of Science & Technology Review, China+1 种基金Project (1960-71131100023) supported by Postgraduate Dissertation Innovation Foundation of Central South University, ChinaProject (ZKJ2009008) supported by Precious Apparatus Opening Center Foundation of Central South University, China
文摘In order to evaluate the spontaneous combustion hazard of sulfide concentrates in storage, three different kinds of sulfide concentrates （sulfur-rich sulfide concentrate, iron sulfide concentrate and copper sulfide concentrate） were obtained from a storage yard in Dongguashan Copper Mine, China. The reaction processes at different heating rates of 5, 10, 15, 20, and 25 ℃/min in air flow from ambient temperature to 1 000 ℃ were studied by TG-DTG-DSC analysis. By the peak temperatures of DTG curves, the whole reaction process for each sample was divided into different stages, and the corresponding apparent activation energies were calculated by the Ozawa-Flynn-Wall method. It is found that the reaction process of each sample is considerably complex; the apparent activation energy values change from 36 to 160 kJ/mol in different temperature ranges; sulfur-rich sulfide and iron sulfide concentrates have lower apparent activation energy than copper sulfide concentrate below 150 ℃; so they are more inclined to cause spontaneous combustion at ambient temperature.
基金Projects(U1637601,51405520,51327902)supported by the National Natural Science Foundation of ChinaProject(ZZYJKT2017-06)supported by State Key Laboratory of High Performance Complex Manufacturing of Central South University,China
文摘To investigate the flow behavior of 2219 Al alloy during warm deformation,the thermal compression test was conducted in the temperature range of 483-573 K and the strain rate range of 0.001-5 s^(-1) on a Gleeble-3500 thermomechanical simulation unit.The true stress-true strain curves obtained showed that the flow stress increased with the decrease in temperature and/or the increase in strain rate and the softening mechanism primarily proceeded via dynamic recovery.The modification on the conventional Arrhenius-type constitutive model approach was made,the material variables and activation energy were determined to be dependent on the deformation parameters.The modified flow stresses were found to be in close agreement with the experimental values.Furthermore,the activation energy obtained under different deformation conditions showed that it decreased with the rise in temperature and/or strain rate,and was also affected by the coupled effect of strain and strain rate.
基金financially supported by the National Natural Science Foundation of China(Nos.52034004 and 51975404)。
文摘The hot deformation behaviors of Ni18 Cr9 Co9 Fe5 Nb3 Mo superalloy were explored in the formation temperature range free ofγ’phase with various strain rates applied.The hot deformation behaviors are initially modeled with Arrhenius equation which gives an average activation energy of 581.1 kJ mol^(-1).A modified Arrhenius approach,including the updated Zener-Hollomon parameter is proposed to consider the change of activation ene rgy under different deformation conditions which turns out a relatively accurate computation for activation energy of hot deformation,i.e.,the standard variance for modified model calculated in the covered deformation condition is just 35.4%of that for Arrhenius equation.The modified model also proposes a map for activation ene rgy which ranges from 571.5-589.0 kJ mol^(-1)for various deformation conditions.Microstructural features of the representative superalloy specimens were characterized by electron backscattered diffraction(EBSD)techniques in order to clarify the influence of activation energy on the microstructural formation.It is found that the Ni-based superalloy samples with higher activation energy are promoted by the degree of dynamic recrystallization which suggests that the rise in activation energy gives either a better recrystallization rate or finer grains.
基金supported by the National Natural Science Foundation of China(No.5087816350708067)+1 种基金the National Major Project of Science&Technology Ministry of China(No.2008ZX07421-002)the Research and Development Project of Ministry of Housing and Urban-Rural Development(No.2009K7-4)
文摘Synthesis and use of the iron compounds supported on granular activated carbon （ICs/GAC） have shown significant environmental implications for perchlorate （ClO4^- ） removal. ICs/GAC was synthesized via hydrolyzing FeSO 4 ·7H2O on GAC, reduced by NaBH 4 solution in polyethylene glycol 6000 and ethanol solution, dried in vacuum condition and exposed to air. Synthesized ICs/GAC was characterized using transmission electron micrograph （TEM）, Brunauer-Emmett-Teller, X-ray photoelectron spectroscopy （XPS）. ICs/GAC was determined to be containing a large amount of FeOHSO 4 , Fe2O3 and a small amount of zero-valent iron （ZVI） nanoparticles according to TEM and XPS measurements. Batch static kinetic tests showed that 97% of ClO4^- was removed within 10 hr at 90°C and 86% of ClO4^- was removed within 12 hr at 25°C, at ICs/GAC dosage of 20 g/L. The experimental results also showed that FeOHSO 4 and Fe 2 O 3 nanoparticles have the function of perchlorate adsorption and play important roles in ClO4^- removal. The activation energy （E a ） was determined to be 9.56 kJ/mol.
基金the National Key Research and Development Program of China(No.2016YFB0301104)Nation Natural Science Foundation of China(No.51771043)Foundation of State Key Laboratory of Baiyunobo Rare Earth researches and Comprehensive Utilization,and Programme of Introducing Talents of Discipline Innovation to Universities 2.0(the 111 Project 2.0 of China,No.BP0719037).
文摘The oxidation behaviors of AZ80,AZ8O-0.32 Y and AZ8O-0.38 Nd(wt.%)alloys were researched at 413℃,420℃,427v and 433℃for up to 6 h in air environment via a high precision analytical balance,a laser confocal microscope,differential scanning calorimeter(DSC)analysis,X-ray diffraction(XRD)analysis,scanning electron microscope(SEM)observation,and X-ray photoelectron spectroscopy(XPS)analysis.The results show that the weight gain and oxidation rate of AZ80 are reduced significantly,the initiation form and propagation of cracks in oxide layer are changed.Compact and protective oxide layer forms on alloy surface with Y or Nd addition.And the activation energies of AZ80,AZ80-0.32Y and AZ8O-0.38Nd alloys calculated via Arrhenius equation are 82.556 kJ/mol,177.148kJ/mol and 136.738 kJ/mol,respectively.
文摘The 4340 steel is extensively utilized in several industries including automotive and aerospace for manufac- turing a large number of structural components. Due to the importance of thermo-mechanical processing in the pro- duction of steels, the dynamic recrystallization （DRX） characteristics of 4340 steel were investigated. Namely, hot compression tests on 4340 steel have been performed in a temperature range of 900-- 1200 ℃ and a strain rate range of 0.01--1 s-1 and the strain of up to 0.9. The resulting flow stress curves show the occurrence of dynamic recrys- tallization. The flow stress values decrease with the increase of deformation temperature and the decrease of strain rate. The microstrueture of 4340 steel after deformation has been studied and it is suggested that the evolution of DRX grain structures can be accompanied by considerable migration of grain boundaries. The constitutive equations were developed to model the hot deformation behavior. Finally based on the classical stress-dislocation relations and the kinematics of the dynamic recrystallization; the flow stress constitutive equations for the dynamic recovery period and dynamic reerystallization period were derived for 4340 steel, respectively. The validity of the model was demon- strated by demonstrating the experimental data with the numerical results with reasonable agreement.
基金Project 50474067 supported by National Natural Science Foundation of China
文摘By analyzing previous studies on activation energy of coal oxidation at low temperatures, a theoretical calculation model of apparent activation energy is established. Yield of CO is measured by using the characteristic detector of coal oxidation at 30-90 ℃. The impact of parameters, such as airflow and particle size, on activation energies is analyzed. Finally, agreement was obtained between activation energies and the dynamic oxygen absorbed in order to test the accuracy of the model. The results show that： 1） a positive exponential relation between concentration of CO and temperature in the process of the experiment is obtained： increases are almost identical and the initial CO is low; 2） the apparent activation energies increase gradually with the sizes of particle at the same airflow, but the gradients increase at a decreasing rate; 3） the apparent activation energies increase linearly with airflow. For the five coal particles, the differences among the energies are relatively high when the airflow was low, but the differences were low when the airflow was high; 4） the optimum sizes of particle, 0.125-0.25 ram, and the optimum volume of airflow, 100 mL/min, are determined from the model; 5） the apparent activation energies decrease with an increase in oxygen absorbed. A negative exponential relation between the two is obtained,
文摘Thermal maturation and petroleum generation modeling of shales is essential for suc- cessful exploration and exploitation of conventional and unconventional oil and gas plays. For basin- wide unconventional resource plays such modeling, when well calibrated with direct maturity meas- urements from wells, can characterize and locate production sweet spots for oil, wet gas and dry gas. The transformation of kerogen to petroleum is associated with many chemical reactions, but models typically focus on first-order reactions with rates determined by the Arrhenius Equation. A miscon- ception has been perpetuated for many years that accurate thermal maturity modeling of vitrinite re- flectance using the Arrhenius Equation and a single activation energy, to derive a time-temperature index （~TTIARa）, as proposed by Wood （1988）, is flawed. This claim was initially made by Sweeney and Burnham （1990） in promoting their ＂EasyRo＂ method, and repeated by others. This paper dem- onstrates through detailed multi-dimensional burial and thermal modeling and direct comparison of the ~TTIARR and ＂EasyRo＂ methods that this is not the case. The ~TTIA^R method not only provides a very useful and sensitive maturity index, it can reproduce the calculated vitrinite reflectance values derived from models based on multiple activation energies （e.g., ＂EasyRo＂）. Through simple expres- sions the ~TTIAaa method can also provide oil and gas transformation factors that can be flexibly scaled and calibrated to match the oil, wet gas and dry gas generation windows. This is achieved in a more-computationally-efficient, flexible and transparent way by the ~TTIARR method than the ＂EasyRo＂ method. Analysis indicates that the ＂EasyRo＂ method, using twenty activation energies and a constant frequency factor, generates reaction rates and transformation factors that do not realisti- cally model observed kerogen behaviour and transformation factors over geologic time scales.
基金financial support from Dr D S Kothari Post-Doctoral Fellowship Scheme,University Grants Commission,New Delhi。
文摘This research work explores the effect of hybrid nanoparticles on the flow over a rotating disk by using an activation energy model.Here,we considered molybdenum disulfide and ferro sulfate as nanoparticles suspended in base fluid water.The magnetic field is pragmatic normal to the hybrid nanofluid flow direction.The derived nonlinear ordinary differential equations are non-dimensionalized and worked out numerically with the help of Maple software by the RKF-45 method.The scientific results for a non-dimensionalized equation are presented for both nanoparticle and hybrid nanoparticle case.Accoutrements of various predominant restrictions on flow and thermal fields are scanned.Computation estimation for friction factor,local Nusselt number and Sherwood number are also executed.Results reveal that the reduction of the heat transfer rate is greater in hybrid nanoparticles when compared to nanoparticles for increasing values of Eckert Number and the thermal field enhances for the enhanced values of volume fraction.
基金Funded by National Natural Science Fundation of China(No.51178455)
文摘Accelerated carbonation experiments about the development of carbonation rates of ordinary Portland cement concrete under different artificial climates were carried out. Six water cement ratios and six climate condition combinations of temperature and relative humidity were used. Results indicate that changes of concrete carbonation rate with environmental temperature agree the Arrhenius law well, which suggests concrete carbonation rate has obvious dependence on temperature. The higher the temperature is, the more quickly the concrete carbonates, and at the same time it is also affected by environmental relative humidity. Thereafter, the apparent activation energy Ea of concrete carbonation reaction was obtained, ranging from 16.8 to 20.6 kJ/mol corresponding 0.35-0.74 water cement ratio, and lower water cement ratio will cause the apparent activation energy increase. Concrete carbonation rates will increase 1.1-1.69 times as temperature increase every 10 ℃ at the temperature range of 10 to 60 ℃.
基金supported by the Key Projects of the National Natural Science Foundation of China (Nos. 51504187, 51774233, and 51704226)Shaanxi Province Industrial Science and Technology Research Project (No. 2016GY-192)the China Postdoctoral Science Foundation (No. 2016-M-590963)
文摘Correlations among free radicals, apparent activation energy, and functional groups during lowtemperature oxidation of Jurassic coal in Northern Shaanxi were investigated by examining three coal samples collected from the Ningtiaota, Jianxin, and Shigetai coal mines. Free radical concentrations at less than 120 ℃ were investigated by electron spin resonance experiments while the thermogravimetric experiments were conducted to analyze apparent activation energies. In addition, Fourier transform infrared spectroscopy was employed to study the spectrum of functional groups generated in coal. The results indicated that, in decreasing order, the apparent activation energies were Shigetai 〉Jianxin 〉 Ningtiaota, indicating that, from 50 to 120 ℃, the Ningtiaota coal sample most easily absorbed and reacted with oxygen while the most resistant was the Shigetai coal sample. Free radical concentrations and line heights increased with increased temperature, and the line width and Lande factor showed irregular fluctuations. Functional group variations were different among these coals, and the phenol and alcohol-associated OHs, carboxyls, and aromatic ring double bonds might have had a major impact on free radical concentrations. These results were meaningful for better consideration and management of coal oxidation at low temperatures.
文摘The present exploration is conducted to describe the motion of viscous fluid embedded in squeezed channel under the applied magnetics effects.The processes of heat and mass transport incorporate the temperature-dependent binary chemical reaction with modified Arrhenius theory of activation energy function which is not yet disclosed for squeezing flow mechanism.The flow,heat and mass regime are exposed to be governed via dimensionless,highly non-linear,ordinary differential equations (ODEs) under no-slip walls boundary conditions.A well-tempered analytical convergent procedure is adopted for the solutions of boundary value problem.A detailed study is accounted through graphs in the form of flow velocity field,temperature and fluid concentration distributions for various emerging parameters of enormous interest.Skin-friction,Nusselt and Sherwood numbers have been acquired and disclosed through plots.The results indicate that fluid temperature follows an increasing trend with dominant dimensionless reaction rate σ and activation energy parameter E.However,an increment in σ and E parameters is found to decline in fluid concentration.The current study arises numerous engineering and industrial processes including polymer industry,compression and injection shaping,lubrication system,formation of paper sheets,thin fiber,molding of plastic sheets.In the area of chemical engineering,geothermal engineering,cooling of nuclear reacting,nuclear or chemical system,bimolecular reactions,biochemical process and electrically conducting polymeric flows can be controlled by utilizing magnetic fields.Motivated by such applications,the proposed study has been developed.
基金the National High Technology Research and Development Program of China(863)(No.2003AA33X100)the National Post Doctoral Fund(No.20060400284)+1 种基金the Jiangshu Province Natural Science Fund(No.BK2005216)the Jiangshu Province Post Doctoral Fund(2006)
文摘The apparent activation energy of concrete in early age was determined by adiabatic temperature rise test with different initial temperatures. The influence of mineral admixtures such as fly ash, slag and silica fume on the apparent activation energy of concrete was investigated. The equivalent age that expresses the maturity of concrete was calculated to evaluate the cracking risk of concrete in structures. The results reveal that a substitution of 20% fly ash for Portland cement obviously decreases the apparent activation energy of concrete, however, a substitution of 10% silica fume for Portland cement increases the apparent activation. Finite element method analysis of a simulating concrete wall shows that the concrete containing 20% fly ash has the lowest cracking risk.
基金United Arab Emirates University,Al Ain,UAE with Grant No.31S363-UPAR(4)2018.
文摘The buoyancy driven flow of a second-grade nanofluid in the presence of a binary chemical reaction is analyzed in the context of a model based on the balance equations for mass,species concentration,momentum and energy.The elastic properties of the considered fluid are taken into account.The two-dimensional slip flow of such non-Newtonian fluid over a porous flat material which is stretched vertically upwards is considered.The role played by the activation energy is accounted for through an exponent form modified Arrhenius function added to the Buongiorno model for the nanofluid concentration.The effects of thermal radiation are also examined.A similarity transformations is used to turn the problem based on partial differential equations into a system of ordinary differential equations.The resulting system is solved using a fourth order RK and shooting methods.The velocity profile,temperature profile,concentration profile,local skin friction,local Nusselt number and local Sherwood number are reported for several circumstances.The influence of the chemical reaction on the properties of the concentration and momentum boundary layers is critically discussed.
基金jointly supported by the National Natural Science Foundation of China (No.61501042)the National High Technology Research and Development Program(863) of China (2015AA016101)+1 种基金Beijing Nova Program(Z151100000315078)Information Network Open Source Platform and Technology Development Strategy(No.2016-XY-09)
文摘Heterogeneous cellular networks(HCNs), by introducing caching capability, has been considered as a promising technique in 5 G era, which can bring contents closer to users to reduce the transmission delay, save scarce bandwidth resource. Although many works have been done for caching in HCNs, from an energy perspective, there still exists much space to develop a more energy-efficient system when considering the fact that the majority of base stations are under-utilized in the most of the time. Therefore, in this paper, by taking the activation mechanism for the base stations into account, we study a joint caching and activation mechanism design to further improve the energy efficiency, then we formulate the optimization problem as an Integer Linear Programming problem(ILP) to maximize the system energy saving. Due to the enormous computation complexity for finding the optimal solution, we introduced a Quantum-inspired Evolutionary Algorithm(QEA) to iteratively provide the global best solution. Numerical results show that our proposed algorithm presents an excellent performance, which is far better than the strategy of only considering caching without deactivation mechanism in the actual, normal situation. We also provide performance comparison amongour QEA, random sleeping algorithm and greedy algorithm, numerical results illustrate our introduced QEA performs best in accuracy and global optimality.
文摘Bioconvection research is primarily focused on the augmentation of energy and mass species,which has implications in the processes intensification,mechanical,civil,electronics,and chemical engineering branches.Advanced bioconvection technology sectors include cooling systems for electronic devices,building insulation,and geothermal nuclear waste disposal.Hence,the present investigation is mainly discoursing the impact of Marangoni convention Casson nanoliquid flow under gyrotactic microorganisms over the porous sheet.The partial differential equations(PDEs)are re-structured into ordinary differential equations(ODEs)via suitable similar variables.These ODEs are numerically solved with the help of the spectral relaxation method(SRM).The numerical outcomes are illustrated graphically for various parameters over velocity,temperature,concentration,and bioconvection profiles.Three-dimensional(3 D)views of important engineering parameters are illustrated for various parameters.The velocity of the Casson nanoliquid increases with increasing the Marangoni parameter but decreases against higher porosity parameter.The surface drag force enhances for enhancement in the Marangoni number.The rate of mass transmission is higher for reaction rate constraint but diminishes for activation energy parameter.The higher radiative values augment the rate of heat transmission.
