Plastic has caused serious"white pollution"to the environment,and the highly inert characteristics of plastic bring a major challenge for *** fluids have unique physical properties and have been widely used ...
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Plastic has caused serious"white pollution"to the environment,and the highly inert characteristics of plastic bring a major challenge for *** fluids have unique physical properties and have been widely used in various *** this work,supercritical CO_(2)(Sc-CO_(2))with mild conditions was selected and assisted by NaOH/HCl solution to degrade polystyrene(PS)plastic,and the reaction model was designed using response surface methodology(RSM).It was found that,regardless of the types of assistance solutions,the factors affecting PS degradation efficiencies were reaction temperature,reaction time,and NaOH/HCl *** the temperature of 400℃,time of 120 min,and base/acid concentration of 5%(in weight),0.15 g PS produced 126.88/116.99±5 mL of gases with 74.18/62.78±5 mL of H2,and consumed 81.2/71.5±5 mL of CO_(2).Sc-CO_(2)created a homogeneous environment,which made PS highly dispersed and uniformly heated,thus promoting the degradation of ***,Sc-CO_(2)also reacted with the degradation products to produce new CO and more CH_(4)and C_(2)H_(x)(x=4,6).Adding NaOH/HCl solution not only improved the solubility of PS in Sc-CO_(2),but also provided a base/acid environment that reduced the activation energy of the reaction,and effectively improved the degradation efficiencies of *** short,degrading PS in Sc-CO_(2)is feasible,and better results are obtained with the assistance of base/acid solution,which can provide a reference for the disposal of waste plastics in the future.
An experimental study on the gravity driven discharge of cohesive particles from a silo with two outlets was *** discharge behaviors under the conditions that a single outlet was open and two outlets were open were in...
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An experimental study on the gravity driven discharge of cohesive particles from a silo with two outlets was *** discharge behaviors under the conditions that a single outlet was open and two outlets were open were investigated by varying the moisture content of the particles and the filling height of the particles in the *** results show that the discharge rate of the cohesive particles increases gradually at the beginning,then almost keeps constant,and finally drops *** discharge rate in case of two openings is around 1.1–1.6 times that in case of a single *** filling height leads to lower discharge rate in case of a single opening but results in higher discharge rate in case of two ***,the avalanche dynamics in case of a single opening was examined,and the mixing behavior of the cohesive particles was *** is observed that the discharge flow is promoted by the avalanche phenomenon in the silo,generating a general trend that the normalized mass of discharge increases with the filling height at higher moisture *** case of a single opening,the transition from mass flow to funnel flow favors the particle mixing,resulting in an increasing mixing index as the moisture content *** general,a better performance of mixing can be achieved in case of a single opening compared with in case of two *** study provides vital information for fundamental understanding of the gravity driven discharge of cohesive particles from the silo with multiple outlets.
Porous cryptomelane-type octahedral molecular sieve(OMS-2)with mixed Mn valence and abundant lattice oxygen species has attracted much attention in volatile organic compounds(VOC)catalytic ***,complete conversion of a...
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Porous cryptomelane-type octahedral molecular sieve(OMS-2)with mixed Mn valence and abundant lattice oxygen species has attracted much attention in volatile organic compounds(VOC)catalytic ***,complete conversion of arene over OMS-2 catalysts at relatively low temperature is still a challenge due to its limited crystal structure and inferior ***,a series of PdCe/OMS-2 catalysts with different Pd/Ce molar ratios was fabricated by a facile impregnation method and the physicochemical properties of which were extensively characterized by X-ray diffraction(XRD),scanning electron microscopy(SEM),high-resolution transmission electron microscopy(HR-TEM),B runauer-Emmett-Teller(BET)method,X-ray fluorescence(XRF),X-ray photoelectron spectroscopy(XPS),temperature programmed reduction of H2(H2-TPR),Raman,In situ diffused reflectance infrared Fourier transform spectra(DRIFTS),and density functional theory(DFT)*** show that the total conversion of toluene can be achieved at 207℃ over PdCe2 with apparent activation energy as low as 62.6 kJ/*** strong synergistic effect between Pd and Ce remarkably boosts the catalytic activity of OMS-2,attributed to the abundant Mn^(3+)-O bands and active surface oxygen *** results reveal that oxygen vacancy can be formed over PdCe2 much easily than that of Pd/OMS-2 and Ce/OMS-2 with the oxygen vacancy formation energy of2.42,2.83 and 2.68 eV,*** increasing the Pd content cannot promote the catalytic activity although PdO is a critical active center in toluene *** vacancy attributed to the integrative effect of Pd,Ce and Mn species plays a promine nt role over prepared catalysts in toluene activation *** findings reported in this work showed new insights into the designing of highly efficient OMS-2catalysts for VOC deep oxidation by tuning oxygen vacancy concentration.
Designing high efficacy photocatalysts is a promising way to improve solar fuel production *** this work,we prepared a core/shell composite of loose ZnCr layered double hydroxide nanosheets modified CdS nanorods for e...
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Designing high efficacy photocatalysts is a promising way to improve solar fuel production *** this work,we prepared a core/shell composite of loose ZnCr layered double hydroxide nanosheets modified CdS nanorods for efficient visible light driven photocatalytic hydrogen *** highest hydrogen production rate achieved 425.8μmol·h^(−1) without adding any noble metal cocatalyst under the visible light stimulus,which is 22.4 times that of 1 wt.%Pt-modified *** corresponding apparent quantum yield is 13.9%at 420 *** is revealed that the synergistic actions of the interfacial redox shuttle of Cr^(3+)/Cr^(δ+)and the interfacial electric field enable the efficient separation of photoinduced charge carriers between two components via a Z-scheme energy band ***,with the hydrogen evolution contribution of Zn^(2+),a remarkable improvement in photocatalytic performance was achieved in contrast to bare *** work provides an effective methodology to construct highly efficient and economically viable photocatalysts for solar H_(2)production and mechanistic study.
The pressure drop prediction of wet gas across single-orifice plate in horizontal pipes had been solved satisfactorily under an annular-mist flow in the upstream of orifice ***,this pressure drop prediction is still n...
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The pressure drop prediction of wet gas across single-orifice plate in horizontal pipes had been solved satisfactorily under an annular-mist flow in the upstream of orifice ***,this pressure drop prediction is still not clearly determined when the upstream is in an intermittent flow or stratified flow,which is corresponding to a region of low FrG(gas phase Froude number)in the flow pattern map of wet *** this study,the wet gas pressure drop across a single-orifice plate was experimentally investigated in the low FrG *** the experiment,the flow pattern transition in the downstream of single-orifice plates,as well as the effects of FrG and FrL(liquid phase Froude number)on UG(gas phase multiplier),were determined and compared when the upstream is in the flow pattern transition and the stratified flow region,*** performances were examined on the available pressure drop *** was found that no model could be capable of jointly predicting the wet gas pressure drop in the low FrG region with an acceptable *** a new method of correlating FrG and FrL simultaneously,new correlations were proposed for the low FrG *** which the modified Chisholm model shows the best prediction accuracies,with the prediction deviations of UG being within 7%and 3%when the upstream is in flow pattern transition and stratified flow region,respectively.
Helium-xenon Brayton cycle systems have significant potential as the energy conversion system for small-scale reactors in remote land,deep-sea,and space applications due to a range of advantages,including high cycle e...
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Helium-xenon Brayton cycle systems have significant potential as the energy conversion system for small-scale reactors in remote land,deep-sea,and space applications due to a range of advantages,including high cycle efficiency,compact system structures,and chemical *** objective of this review is to provide a comprehensive understanding of the helium-xenon Brayton cycle system based on the projects and ***,the basic information and development history are introduced,and a series of typical designs are ***,the system configurations,cycle parameter analysis and optimization are ***,the key components are classified,such as turbine,compressor,and heat ***,the dynamic processes and control strategies are introduced in different ***,the deficiency and prospect of current research are *** review covers the representative helium-xenon Brayton cycle systems,which could provide a reference for promoting the development of energy conversion systems.
In this study,the multi-objective intelligent optimization of the crevice structure in a rapid compression machine(RCM)is carried out based on the RCM simulation model modified with the KIVA-3V program.A multi-objecti...
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In this study,the multi-objective intelligent optimization of the crevice structure in a rapid compression machine(RCM)is carried out based on the RCM simulation model modified with the KIVA-3V program.A multi-objective optimization simulation model of the crevice structure based on the large eddy simulation model coupled with the genetic algorithm NSGA-Ⅲis *** optimization parameters and seven optimization objectives are selected in the optimization *** results show that the genetic algorithm can quickly find the values of the optimized *** crevice volume ratio shows a trade-off relationship with the dimensionless temperature ratio T_(max)/T_(aver)and the tumble ratio.A larger crevice volume can reduce the flow of boundary layer cryogenic gas into the combustion chamber,thus improving the temperature *** addition,the crevice entrance width and the connecting channel length should be smaller,while the volume of the crevice main chamber should be larger,so as to sufficiently introduce the low-temperature gas of the boundary layer into the crevice and reduce their influence on the temperature field of the combustion *** the crevice volume accounts for10%of the total volume,the temperature uniformity of the combustor is significantly enhanced,and when the crevice volume accounts for 30.4%,there is almost no low-temperature vortex in the combustion chamber.
This paper focuses on the laminar flame instability of three high molecular weight n-alkanes,namely n-hexane,n-octane,and *** experiment was carried out in a constant volume combustion bomb to get the flame *** critic...
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This paper focuses on the laminar flame instability of three high molecular weight n-alkanes,namely n-hexane,n-octane,and *** experiment was carried out in a constant volume combustion bomb to get the flame *** critical radius under different conditions was extracted using the image processing *** with the existing critical Peclet number theory,the dominant factors of flame instability under current conditions for three n-alkanes can be figured ***,the average cell size(equivalent cell radius,R_(cell))was extracted to provide quantitative analysis of the flame cellular structure,based on the method developed in this *** theoretical R_(cell)were also calculated and compared with the experimental results to validate the proposed method.
External Reactor Vessel Cooling (ERVC) is a key measure to realize molten corium In-Vessel Retention (IVR). The uncertainty of severe accident in core leads to the uncertainty of molten pool parameters in lower head, ...
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Induced-charge electro-osmosis(ICEO)is a research hotspot in bioengineering and analytical ***-outflow asymmetry of ICEO was reported in the existing literatures,but systematic study on this phenomenon is *** this exp...
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Induced-charge electro-osmosis(ICEO)is a research hotspot in bioengineering and analytical ***-outflow asymmetry of ICEO was reported in the existing literatures,but systematic study on this phenomenon is *** this experimental study,we found that in strong electric fields,not only the velocity magnitude but also the vortex positions of ICEO are asymmetrical along the inflow and outflow directions because of the pronounced non-uniform surface electrokinetic *** the inflow and outflow directions,the amplitudes of velocities are unequal,ICEO maximum velocity positions change depending on the electric field intensity and sodium chloride(NaCl)***,the distances between vortex centers are *** NaCl solution concentration of 0.001 mol⋅L^(-1),the outflow velocity almost *** asymmetry rises with the increasing electric field *** new discoveries can direct the application of microscale devices.
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