Mass transfer mechanism and relationship of gas–liquid annular flow in a microfluidic cross-junction device

Mass transfer performance of gas–liquid two-phase flow at microscale is the basis of application of microreactor in gas–liquid reaction systems.At present,few researches on the mass transfer property of annular flow have been reported.Therefore,the mass transfer mechanism and relationship of gas–liquid annular flow in a microfluidic cross-junction device are studied in the present study.We find that the main factors,i.e.,flow pattern,liquid film thickness,liquid hydraulic retention time,phase interface fluctuation,and gas flow vorticity,which influence the flow mass transfer property,are directly affected both by gas and liquid flow velocities.But the influences of gas and liquid velocities on different mass transfer influencing factors are different.Thereout,the fitting relationships between gas and liquid flow velocities and mass transfer influencing factors are established.By comparing the results from calculations using fitting equations and simulations,it shows that the fitting equations have relatively high degrees of accuracy.Finally,the Pareto front,namely the Pareto optimal solution set,of gas and liquid velocity conditions for the best flow mass transfer property is obtained using the method of multi-objective particle swarm optimization.It is proved that the mass transfer property of the gas–liquid two-phase flow can be obviously enhanced under the guidance of the obtained Pareto optimal solution set through experimental verification.

Emerging Flexible Thermally Conductive Films:Mechanism,Fabrication,Application

Effective thermal management is quite urgent for electronics owing to their ever-growing integration degree,operation frequency and power density,and the main strategy of thermal management is to remove excess energy from electronics to outside by thermal conductive materials.Compared to the conventional thermal management materials,flexible thermally conductive films with high in-plane thermal conductivity,as emerging candidates,have aroused greater interest in the last decade,which show great potential in thermal management applications of next-generation devices.However,a comprehensive review of flexible thermally conductive films is rarely reported.Thus,we review recent advances of both intrinsic polymer films and polymer-based composite films with ultrahigh in-plane thermal conductivity,with deep understandings of heat transfer mechanism,processing methods to enhance thermal conductivity,optimization strategies to reduce interface thermal resistance and their potential applications.Lastly,challenges and opportunities for the future development of flexible thermally conductive films are also discussed.

A force transfer mechanism for triggering landslides during rainfall infiltration

Shallow slope failures induced by rainfall infiltration occur frequently, and the relevant triggering mechanisms have been widely studied.Rainfall-induced landslides are widely recognized to be caused by increases in soil weight, seepage force and pore water pressure or decreases in soil mechanical properties. However, even when all these factors are considered, some landslides still cannot be explained well. The increased pore water pressure in a slope reduces the effective stress of the soil and may trigger slope failure. Similarly, the pore gas pressure in a slope also reduces the effective stress of the soil but has been neglected in previous studies. As the viscosity of air is nearly negligible when compared with that of water, the pore gas pressure spreads faster, and its influence is wider, which is harmful for the stability of the slope. In this paper, the effects of pore gas pressure are considered in a shallow slope stability analysis, and a self-designed experiment is conducted to validate the force transfer mechanism.Numerical simulation results show that the pore gas pressure in the slope increases sharply at different locations under heavy rainfall conditions and that the pore gas pressure causes a rapid decrease in the slope safety factor. Laboratory experimental results show that the pore gas pressure throughout the whole unsaturated zone has the same value, which indicates that the gas pressure could spread quickly to the whole sample.

Energy transfer mechanism of Sr_4Al_(14)O_(25):Eu^(2+) phosphor

Long lasting blue-green-emitting Sr4Al14O25:Eu2+ phosphors were synthesized by solid-state reactions.The phosphors were investigated by X-ray diffraction(XRD) and fluorescence spectrophotometer.A pure phase of Sr4Al14O25:Eu2+ phosphor was obtained at 1250 °C.There are two different types of Eu emission centers in Sr4Al14O25:Eu2+ phosphor.The effects of the Eu2+ concentration and the reducing temperature on the distribution of Eu2+ among different sites were investigated.The energy transfer mechanism between...

Uplift behavior and load transfer mechanism of prestressed high-strength concrete piles

Prestressed high-strength-concrete (PHC) tube-shaped pile is one of the recently used foundations for soft soil. The research on uplift resistance of PHC pile is helpful to the design of pile foundations. A field-scale test program was conducted to study the uplift behavior and load transfer mechanism of PHC piles in soft soil. The pullout load tests were divided into two groups with different diameters, and there were three piles in each group. A detailed discussion of the axial load transfer and pile skin resistance distribution was also included. It is found from the tests that the uplift capacity increases with increasing the diameter of pile. When the diameter of piles increases from 500 to 600 mm, the uplift load is increased by 51.2%. According to the load-displacement (Q-S) curves, all the piles do not reach the ultimate state at the maximum load. The experimental results show that the piles still have uplift bearing capacity.

MECHANISM FOR THE INITIATION OF ACRYLONITRILE POLYMERIZATION BY POLYPROPYLENE-BASED POLYAMIDOXIME-THIOUREA COMBINATION

Polymerization of acrylonitrile (AN) in aqueous nitric acid initiated by polypropylene-based polyamidoxime (PPAO)-thiourea (TU) combination has been investigated. The overall rate of polymerization (R_p) under the conditions of [TU]/[PPAO]<0.5 molar ratio isThe molecular weights of the polymers were found to be inversely proportional to 3/2-power of nitric acid concentration and 1-power of thiourea concentration. In addition, it is independent with the concentrations of monomer and PPAO, and decreases with increasing temperature.On the basis of these experimental results, a coordination-proton transfer mechanism for the initiation was proposed and discussed.

Mass and heat transfer mechanism in wood during radio frequency/vacuum drying and numerical analysis

The mass and heat transfer mechanisms during radio frequency/vacuum （RF/V） drying of square-edged timber were analyzed and discussed in detail, and a new one-dimensional mathematical model to describe the transport phenomena of mass and heat during continuous RF/V drying was derived from conservation equations based on the mass and heat transfer theory of porous materials The new model provided a relatively fast and efficient way to simulate vacuum drying behavior assisted by dielectric heating. Its advantages compared with the conventional models include： （1） Each independent vari- able has a separate control equation and is solved inde- pendently by converting the partial differential equation into a difference equation with the finite volume method; （2） The calculated data from different parts of the specimen can be displayed in the evolution curves, and the change law of the,parameters can be better described. After analyzing the calculated results, most of the important phenomena observed during RF/V drying were adequately described by this model.

THE STUDY ON THE MASS TRANSFER MECHANISM OF EUROPIUM ION THROUGH LIQUID SURFACTANT MEMBRANES

The transfer of trivalent europium ion in a liquid surfactant membrane system is investigated in order toclarify the characteristics of liquid membrane separation process and the availability of this technique forrecovering trivalent lanthanides and actinides.A layered structure model for the emulsion globule is sug-gested.The equations describing the relationship among the effective membrane thickness,the time andother factors are derived and verified experimentally.Results show that under certain conditions the decreas-ing concentration of europium ion in the external phase is proportional to the square root of the time,the acidity of the internal phase and the carrier concentration in the membrane phase.The membrane phase consists of kerosene（solvent）,Span-80（surfactant）and di-（2-ethylhexyl） phosphoricacid（HDEHP,carrier）.The internal phase is dilute nitric acid and the external phase is aqueous solu-tion containing Eu（NO3）3.The mass transfer rate of europium in this system is high and the recovery ofeuropium may be more than 99%.

Mechanism of Excited State Double Proton Transfer in 2-Amino-3-Methoxypyridine and Acetic Acid Complex

The excited-state double-proton transfer （ESDPT） mechanism of 2-amino-3-methoxypyridine and acetic acid com- plex is studied by the density functional theory （DFT） and time-dependent DFT with CAM-B3LYP functional. The complex is connected through two different types of inter-molecular hydrogen bonds. After photo-excitation, both hydrogen bonds get strengthened, which can facilitate the ESDPT reaction. The scanned potential energy curve along the proton transfer coordinate indicates that the ESDPT reaction proceeds in a stepwise pattern.

Electrochemical Biorefinery toward Chemicals Synthesis and Bio-Oil Upgrading from Lignin

Recalcitrance and the inherent heterogeneity of lignin structure are the major bottlenecks to impede the popularization of lignin-based chemicals production processes.Recent works suggested a promising pathway for lignin depolymerization and lignin-derived bio-oil upgrading via an electrochemical biorefinery(a process in which lignin valorization is performed via electrochemical oxidation or reduction).This review presents the progress on chemicals synthesis and bio-oil upgrading from lignin by an electrochemical biorefinery,relating to the lignin biosynthesis pathway,reaction pathway of lignin electrochemical conversion,inner-sphere and outer-sphere electron transfer mechanism,basic kinetics and thermodynamics in electrochemistry,and the recent embodiments analysis with the emphasis on the respective feature and limitation for lignin electrochemical oxidative and reductive conversion.Lastly,the challenge and perspective associated with lignin electrochemical biorefinery are discussed.Present-day results indicate that more work should be performed to promote efficiency,selectivity,and stability in pursuing a lignin electrochemical biorefinery.One of the most promising developing directions appears to be integrating various types of lignin electrochemical conversion strategies and other existing or evolving lignin valorization technologies.This review aims to provide more references and discussion on the development for lignin electrochemical biorefinery.

Decoding the nature of interaction between felsic clasts and mafic magma in a subvolcanic magma chamber from amphibole–titanite transformation and chemistry

The Ghansura Rhyolite Dome of Bathani vol-cano-sedimentary sequence,eastern India,represents a subvolcanic felsic magma chamber that was invaded by crystal-rich mafic magma during its cooling phase to form an assortment of hybrid rocks.A prominent solidified portion of the magma reservoir was embedded in the intruding mafic magma as fragments or clasts that pro-duced mafic rocks with felsic clasts.Two distinct compo-sitional zones could be identified in the mafic rocks containing felsic clasts-(a)medium-grained mafic zones that are dominated by amphiboles,and(b)fine-grained felsic zones consisting primarily of quartz and feldspar.Amphiboles occur in most of the felsic clasts suggesting the mechanical transfer of crystals from the mafic to the felsic zones.Compositions of amphiboles were determined from both the mafic and felsic zones that show linear compositional variation from actinolite to ferro-hornblende through magnesio-hornblende,suggesting the interplay of complex substitutions in individual amphibole sites.Cationic schemes have confirmed the role of pargasite(Pg)-type substitution,which is a combination of edenite(Ed)-and tschermakite(Ts)-type substitutions.Moreover,amphibole has been extensively replaced by titanite in the studied rock.Titanite produced in the mafic zones due to the destabilization of amphiboles was observed migrating from the mafic to the felsic zones through mineral-trans-porting veins.Compositions of titanite were determined from grains that occur in association with amphiboles and those which are present as individual entities in the felsic zones.Similar to amphiboles,titanite also displays cationic substitutions in the studied rock.From the results presented in this work,we infer that extensive replacement of amphibole by titanite and cationic substitutions in amphi-boles,and also titanite,may be considered important pet-rogenetic indicators to decipher magma mixing events.

Stress response characteristics of BFRP anchors on loess mudstone slope under rainfall conditions

To investigate the stress response characteristics and shear stress transfer mechanism of BFRP(basalt fiber reinforced plastics)anchors under rainfall conditions and to explore the reinforcement effect of BFRP anchors,a comparative indoor physical model test was conducted in this study using loess mudstone slope as a typical case,and multi-attribute response data,such as slope displacement,BFRP anchor strain and axial force,were obtained.Based on the variation law of slope displacement,it can be concluded that the deformation displacement of the slope on the side reinforced by BFRP anchors is smaller than that of slopes reinforced with steel anchors;the bearing capacity of BFRP anchor is given priority in time,and the anchoring effect of BFRP anchor at the top of the slope is given priority,and the axial force value of anchor is characterized by a surface amplification effect in space;the axial force is higher around the anchor head and tends to decay as a negative exponential function as the anchor extends in the direction of the interior of the slope;the shear stress of BFRP anchor and anchorage body are unevenly distributed along the axial direction,with the maximum value occurring in the free section near the slope surface and decreases as the BFRP anchor extends towards the interior of the slope.These results can provide a theoretical basis for the optimal design of BFRP anchors.

Tiêu Equation Experimentation of Understanding by Energy Transfer Quantum Mechanics

Background: The Tiêu equation has a ground roots approach to the process of Quantum Biology and goes deeper through the incorporation of Quantum Mechanics. The process can be measured in plant, animal, and human usage through a variety of experimental or testing forms. Animal studies were conducted for which, in the first day of the study all the animals consistently gained dramatic weight, even as a toxic substance was introduced as described in the introduction of the paper to harm animal subjects which induced weight loss through toxicity. Tests can be made by incorporating blood report results. Human patients were also observed to show improvement to their health as administration of the substance was introduced to the biological mechanism and plants were initially exposed to the substance to observe results. This is consistent with the Tiêu equation which provides that wave function is created as the introduction of the substance to the biological mechanism which supports Quantum Mechanics. The Tiêu equation demonstrates that Quantum Mechanics moves a particle by temperature producing energy thru the blood-brain barrier for example. Methods: The methods for the Tiêu equation incorporate animal studies to include the substance administered through laboratory standards using Good Laboratory Practices under Title 40 C.F.R. § 158. Human patients were treated with the substance by medical professionals who are experts in their field and have knowledge to the response of patients. Plant applications were acquired for observation and guidance of ongoing experiments of animals’ representative for the biologics mechanism. Results: The animal studies along with patient blood testing results have been an impressive line that has followed the Tiêu equation to consistently show improvement in the introduction of the innovation to biologic mechanisms. The mechanism responds to the substance by producing energy to the mechanism with efficient effect. For plant observations, plant organisms responded, and were seen as showing improvement thru visual observation.

Decomposition of a β-O-4 lignin model compound over solid Cs-substituted polyoxometalates in anhydrous ethanol: acidity or redox property dependence?

Production o f aromatics from lignin has attracted much attention. Because of the coexistence of C-O and C-C bonds and their complex combinations in the lignin macromolecular network, a plausible roadmap for developing a lignin catalytic decomposition process could be developed by exploring the transformation mechanisms of various model compounds. Herein, decomposition of a lignin model compound, 2-phenoxyacetophenone （2-PAP）, was investigated over several ce-sium-exchanged polyoxometalate （Cs-POM） catalysts. Decomposition of 2-PAP can follow two dif-ferent mechanisms： an active hydrogen transfer mechanism or an oxonium cation mechanism. The mechanism for most reactions depends on the competition between the acidity and redox proper-ties of the catalysts. The catalysts of POMs perform the following functions： promoting active hy-drogen liberated from ethanol and causing formation of and then temporarily stabilizing oxonium cations from 2-PAP. The use of Cs-PMo, which with strong redox ability, enhances hydrogen libera-tion and promotes liberated hydrogen transfer to the reaction intermediates. As a consequence, complete conversion of 2-PAP （〉99%） with excellent selectivities to the desired products （98.6% for phenol and 91.1% for acetophenone） can be achieved.

Formation of BiOI/g-C_3N_4 nanosheet composites with high visible-light-driven photocatalytic activity

Constructing binary heterojunctions is an important strategy to improve the photocatalytic performance of graphitic carbon nitride(g‐C3N4).In this paper,a novel g‐C3N4 nanosheet‐based composite was constructed via in situ growth of bismuth oxyiodide(BiOI)nanoplates on the surface of g‐C3N4 nanosheets.The crystal phase,microstructure,optical absorption and textural properties of the synthesized photocatalysts were analyzed by X‐ray diffraction(XRD),scanning electron microscopy(SEM),transmission electron microscopy(TEM),ultraviolet‐visible(UV‐vis)diffuse reflectance spectroscopy(DRS),and nitrogen adsorption‐desorption isotherm measurements.The BiOI/g‐C3N4 nanosheet composite showed high activity and recyclability for the photodegradation of the target pollutant rhodamine B(RhB).The conversion of RhB(20 mg L?1)by the photocatalyst was nearly 100%after 50 min under visible‐light irradiation.The high photoactivity of the BiOI/g‐C3N4 nanosheet composite can be attributed to the enhanced visible‐light absorption of the g‐C3N4 nanosheets sensitized by BiOI nanoplates as well as the high charge separation efficiency obtained by the establishment of an internal electric field between the n‐type g‐C3N4 and p‐type BiOI.Based on the characterization and experimental results,a double‐transfer mechanism of the photoinduced electrons in the BiOI/g‐C3N4 nanosheet composite was proposed to explain its activity.This work represents a new strategy to understand and realize the design and synthesis of g‐C3N4 nanosheet‐based heterojunctions that display highly efficient charge separation and transfer.

Displacement and deformation analysis for uplift piles

On the assumptions that the shear resistance increases linearly with increasing shear displacement between the uplift pile and surrounding soil, that the axis force is distributed as parabola along the pile length, that elastic distortion occurs when the pile is loaded, that the displacement of pile is in accord with that of the soil, and that the uplift pile failure is regarded as the soil failure, a rational calculation method was proposed for calculating the deformation, ultimate displacement and shear resistance of piles. The distributions of frictional resistance and the shear displacement along the pile length were obtained with the method. The comparisons were made between the measurement results and the present results. The present theoretical results agree well with the measurement results, with the average difference being less than 12% before failure. The comparisons show that the proposed method is reasonable for uplift design and engineering construction of piles.

Characterization of Low Pressure RF Plasma Heating

Compacts of a-Al2O3 and Mo powder were heated in radio-frequency (RF) induced low pressure N2, H2,Ar, and their mixture plasma. An optical pyrometer, a radiation pyrometer, and a system called Accufiber Model310 were used to measure the temperature of compacts heated in the plasma. The results indicate that there are different heat transfer mechanisms from plasma to specimens of different physical properties. The Ar plasma showed thehighest heating ability among N2, H2, and Ar plasma for Al2O3 specimens, whereas the H2 plasma could heat Mospecimens to a higher temperature than the Ar plasma did, even under the same generating conditions.

Analysis profile of the fully grouted rock bolt in jointed rock using analytical and numerical methods

The purpose of this study was to investigate the effect of bolt profile on load transfer mechanism of fully grouted bolts in jointed rocks using analytical and numerical methods. Based on the analytical method with development of methods, a new model is presented. To validate the analytical model, five different profiles modeled by ANSYS software. The profile of rock bolts T3 and T4with load transfer capacity,respectively 180 and 195 kN in the jointed rocks was selected as the optimum profiles. Finally, the selected profiles were examined in Tabas Coal Mine. FLAC analysis indicates that patterns 6+7 with2 NO flexi bolt 4 m better than other patterns within the faulted zone.

Research on Coupling Transfer Characteristics of Vibration Energy of Free Piston Linear Generator

In order to clarify the mechanism and main influencing factors of the vibration energy coupling transmission with a dual-piston structure,a thermodynamic and dynamic coupling model of the free piston linear generator(FPLG)was established.The system energy conversion,vibration energy coupling transmission,and influencing factors were studied in detail.The coupling transmission paths and the secondary influence mechanism from in-cylinder combustion on vibration energy transmission were obtained.In addition,the influence of the movement characteristics of the dual-piston on the vibration energy transmission was studied,and the typical parameter variation law was obtained,which provides theoretical guidance for the subsequent vibration reduction design of the FPLG.

Bearing Behaviors of Stiffened Deep Cement Mixed Pile

A series of investigations were conducted to study the bearing capacity and load transfer mechanism of stiffened deep cement mixed （SDCM） pile. Laboratory tests including six specimens were conducted to investigate the frictional resistance between the concrete core and the cementsoil. Two model piles and twenty-four full-scale piles were tested to examine the bearing behavior of single pile. Laboratory and model tests results indicate that the cohesive strength is large enough to ensure the interaction between core pile and the outer cement-soil. The full-scale test results show that the SDCM piles exhibit similar bearing behavior to bored and cast-in-place concrete piles. In general, with the rational composite structure the SDCM piles can transmit the applied load effectively, and due to the addition of the stiffer core, the SDCM piles possess high bearing capacity. Based on the findings of these experimental investigations and theoretical analysi , a practical design method is developed to predict the vertical bearing capacity of SDCM pile.