Computational Mass Transfer Method for Chemical Process Simulation

The recent works on the development of computational mass transfer （CMT） method and its applications in chemical process simulation are reviewed. Some development strategies and challenges in future research are also discussed.

Heat and Mass Transfer in MHD Visco-Elastic Fluid Flow through a Porous Medium over a Stretching Sheet with Chemical Reaction

This paper presents the study of convective heat and mass transfer characteristics of an incompressible MHD visco-elastic fluid flow immersed in a porous medium over a stretching sheet with chemical reaction and thermal stratification effects. The resultant governing boundary layer equations are highly non-linear and coupled form of partial differential equations, and they have been solved by using fourth order Runge-Kutta integration scheme with Newton Raphson shooting method. Numerical computations are carried out for the non-dimensional physical parameters. Here a numerical has been carried out to study the effect of different physical parameters such as visco-elasticity, permeability of the porous medium, magnetic field, Grashof number, Schmidt number, heat source parameter and chemical reaction parameter on the flow, heat and mass transfer characteristics.

Simultaneous effects of chemical reaction and Ohmic heating with heat and mass transfer over a stretching surface: A numerical study

In this article, we have considered the simultaneous influence of ohmic heating and chemical reaction on heat and mass transfer over a stretching sheet. The effects of applied magnetic field are also taken into consideration while the induced magnetic field is not considered due to very small magnetics Reynolds number. The governing flow problem comprises of momentum, continuity, thermal energy and concentration equation which are transformed into highly nonlinear coupled ordinary differential equations by means of similarity transforms, which are then, solved numerically with the help of Successive Linearization method(SLM) and Chebyshev Spectral collocation method. Numerical values of skin friction coefficient, local Nusselt number, and Sherwood number are also taken into account with the help of tables. The physical influence of the involved parameters of flow velocity, temperature and concentration distribution is discussed and demonstrated graphically. The numerical comparison is also presented with the existing published results and found that the present results are in excellent agreement which also confirms the validity of the present methodology.

Mass and chemical changes of immobile elements in Yamaghan Occurrence, Zanjan Province, Iran

Using mass and chemical changes, behavior of some elements have been evaluated in the study area, Yamaghan Occurrence. The techniques using immobile elements can precisely identify altered volcanic rock precursors and measure material changes. The rocks of the study area were affected by hydrothermal alteration. Testing of some compatible incompatible and compatible compatible immobile pairs indicates that Al 2O 3 is the most immobile component in the study area. It means that during the three main stages of hydrothermal alteration (phyllic, intermediate argillic and propylitic) aluminum was the most immobile and titanium was slightly immobile. Increases in mass mostly result from mineralization, silicification or carbonatization as voids and other open space fillings and may have replaced the part of glassy matrix. Mass addition has diluted the immobile elements at constant rates. Mass loss is commonly due to leaching of Si, Ca and Na 2O during chloritization and sericitization. The mass loss is recognized by increased proportions of inert minerals such as chlorite and sericite. Mineralographic studies in the study area shows the existence of a supergene zone. Calcocite and covellite are considered enriched minerals. Considering this evidence and mass change results, the enrichment of copper in the circulating fluid is suspected with occasional sulfide precipitation.

MHD flow and mass transfer of chemically reactive upper convected Maxwell fluid past porous surface

The magnetohydrodynamic （MHD） flow and mass transfer of an electrically conducting upper convected Maxwell （UCM） fluid at a porous surface are studied in the presence of a chemically reactive species. The governing nonlinear partial differential equations along with the appropriate boundary conditions are transformed into nonlinear ordinary differential equations and numerically solved by the Keller-box method. The effects of various physical parameters on the flow and mass transfer characteristics are graphically presented and discussed. It is observed that the order of the chemical reaction is to increase the thickness of the diffusion boundary layer. Also, the mass transfer rate strongly depends on the Schmidt number and the reaction rate parameter. Furthermore, available results in the literature are obtained as a special case.

Source Apportionment of Ambient PM_(10) in the Urban Area of Longyan City,China:a Comparative Study Based on Chemical Mass Balance Model and Factor Analysis Method

In order to identify the day and night pollution sources of PM10 in ambient air in Longyan City,the authors analyzed the elemental composition of respirable particulate matters in the day and night ambient air samples and various pollution sources which were collected in January 2010 in Longyan with inductivity coupled plasma-mass spectrometry（ICP-MS）.Then chemical mass balance（CMB） model and factor analysis（FA） method were applied to comparatively study the inorganic components in the sources and receptor samples.The results of factor analysis show that the major sources were road dust,waste incineration and mixed sources which contained automobile exhaust,soil dust/secondary dust and coal dust during the daytime in Longyan City,China.There are two major sources of pollution which are soil dust and mixture sources of automobile exhaust and secondary dust during the night in Longyan.The results of CMB show that the major sources are secondary dust,automobile exhaust and road dust during the daytime in Longyan.The major sources are secondary dust,soil dust and automobile exhaust during the night in Longyan.The results of the two methods are similar to each other and the results will guide us to plan to control the PM10 pollution sources in Longyan.

Microinterfacial technology enhancing mass transfer in chemical engineering

The microbubble and microinterface play key roles in the development and progress of the technology in the field of chemical engineering,which has attracted broad attention from the scientific and industrial community.Recently,Zhang et al.published a book about microinterfacial mass transfer intensification technology,where they systematically introduced scientific essence,reaction mechanism,equipment structure,and influence law of multiphase reaction process strengthened by microinterface.I believe this book can promote the technological innovation of microbubble-related processes,and also the development of the green chemical industry!

Thermal Diffusion Effect on MHD Heat and Mass Transfer Flow past a Semi Infinite Moving Vertical Porous Plate with Heat Generation and Chemical Reaction

The objective of present work is to study the thermo diffusion effect on an unsteady simultaneous convective heat and mass transfer flow of an incompressible, electrically conducting, heat generating/absorbing fluid along a semi-infinite moving porous plate embedded in a porous medium with the presence of pressure gradient, thermal radiation field and chemical reaction. It is assumed that the permeable plate is embedded in a uniform porous medium and moves with a constant velocity in the flow direction in the presence of a transverse magnetic field. It is also assumed that the free stream consists of a mean velocity, temperature and concentration over which are super imposed an exponentially varying with time. The equations of continuity, momentum, energy and diffusion, which govern the flow field, are solved by using a regular perturbation method. The behavior of the velocity, temperature, concentration, Skin-friction, rate of heat transfer and rate of mass transfer has been discussed for variations in the physical parameters. An increase in both Pr and R results a decrease in thermal boundary layer thickness. However, concentration decreases as Kr, Sc increase but it increases with an increase in both So and δ.

MASS BALANCES OF MAJOR CHEMICAL CONSTITUENTS IN BOHAI SEA WATER Ⅱ.REMOVAL PROCESSES

The removal processes of major seawater chemical constituents in the Bohai Sea include seawater ex-change between the Bohai Sea and the Northern Yellow Sea,cation exchange,interstitial water burialand spray,formation of illite,sepiolite,sulfate and sulfur,and carbonates.The mass balance calculationbased on these processes is very applicable to the Bohai Sea.

MASS BALANCES OF MAJOR CHEMICAL CONSTITUENTS IN BOHAI SEA WATER I. SOURCES

Because of the almast enclosed nature of the Bohai Sea, rivers are considered as the sources of the major seawater chemical constituents there. The annual quantities of river-derived solutes and solids in Bohai Sea water are accurately calculated in this paper.

Mixed convection effects on heat and mass transfer in a non Newtonian fluid with chemical reaction over a vertical plate

This paper studies mixed convection,double dispersion and chemical reaction effects on heat and mass transfer in a non-Darcy non-Newtonian fluid over a vertical surface in a porous medium under the constant temperature and concentration.The governing boundary layer equations,namely,momentum,energy and concentration,are converted to ordinary differential equations by introducing similarity variables and then are solved numerically by means of fourth-order Runge-Kutta method coupled with double-shooting technique.The velocity,temperature concentration,heat and mass transfer profiles are presented graphically for various values of the parameters,and the influence of viscosity index n,thermal and solute dispersion,chemical reaction parameter χ are observed.

Influence of Finite Chemical Potential on Critical Boson Mass in QED3

Using the coupled Dyson-Schwinger equation for the fermion propagator at finite chemical potential μ, we investigate the fermion chiral condensate when the gauge boson mass is nonzero in QED3. We show that the chiral symmetry restores when the boson mass is large enough, and the critical boson mass depends little on μ.

Elemental Compositions and Chemical Mass Closure of Fine Particulate in an Animal Feeding Operation Facility and Its Vicinity

Particulate matter (PM) emissions from animal feeding operations (AFOs) have been considered as an important contributor to ambient PM in rural areas. Investigation of the chemical compositions of PM2.5 inside and in the vicinity of AFOs can enhance our understanding of the AFO emissions impact on ambient PM characteristics. This year-long field study was conducted on a commercial egg production farm to investigate ambient PM chemical compositions as impacted by the air emissions from the production houses. The PM2.5 samples were collected from five sampling stations (one in-house station and four ambient locations in four wind directions). The trace elements, major ions, organic carbon (OC) and element carbon (EC) were analyzed by X-ray florescence (XRF), ion chromatography (IC), and thermo-optical analyzer, respectively. There were significant differences in elemental compositions between PM samples from in-house station (ST1) and ambient stations (ST2-ST5). The chemical mass balance analysis revealed that OC accounted for above 50% of PM2.5 mass at in-house and ambient stations;NH4+, SO42-, and NO3- accounted for about 40.0% of the total PM2.5 mass in ambient locations and for only 12% of the total PM2.5 mass in house. The measured PM2.5 masses agreed with the sums of the masses of chemical compositions at all stations except for the in-house station. Knowledge gained from this study, with additional consideration of NH3 concentrations and emissions, will lead to better understanding of PM2.5 source and formation, fate and transport, and their atmospheric dynamics.

MHD Heat and Mass Transfer of an Oscillatory Flow over a Vertical Permeable Plate in a Porous Medium with Chemical Reaction

The problem of magneto-hydro-dynamic (MHD) mass and heat transfer of an oscillatory fluid in two-dimensional viscous, electrically conducting over an infinite vertical permeable moving plate in a saturated porous medium with the presence of a transverse magnetic field and chemical reaction is analytically presented. The governing equations, momentum, energy, and concentration are solved. Various flow parameters effects on velocity, temperature and concentration fields are discussed. It is found that, the fluid velocity increases with increasing both the permeability and chemical reaction parameters. While, it increases with decreasing the magnetic field parameter. Furthermore, the concentration increases with increasing chemical reaction parameters.

Chemical Selectivity of Laser Ion Source for on-Line Mass Separator

Thulium(Tm)atoms are resonantly ionized in a hot tube by stepwise excitations us-ing three dye lasers pumped by a series of copper vapor pulsed at a 10 kHz rate.The chemicalselectivity of the laser ion source is measured as a function of temperature of the tubes made ofTa,Nb-Zr and TaC.The chemical selectivity rises from 50 to 10000 with decreasing tube temp-erature and strongly depends on the tube material.A chemical selectivity of about 10000 withhigh efficiencies is obtained with the Nb-Zr and TaC tubes.Such a laser ion source can be usedin on-line mass separator to obtain isobarically pure ion beams.

Chemical Components of Achyranthes bidentata Leaves by Ultra High Performance Liquid Chromatography-Mass Spectrometry

[Objectives] To study the chemical components and relative content of Achyranthes bidentata leaves and provide a scientific basis for further development and utilization of A. bidentata leaves.[Methods] The chemical components of A. bidentata leaves were rapidly analyzed using the ultra high performance liquid chromatography-time of flight-high resolution mass spectrometry (UHPLC-TOF-MS).[Results] Thirty eight chemical compounds were identified in samples of A. bidentata leaves collected from Wen County of Henan Province, in which seven chemical compounds had the relative content higher than 5%, linoleic acid reached 25.7% and inokosterone A reached 13.8%.[Conclusions] A. bidentata leaves contain many kinds of chemical compounds. This study is expected to provide a certain basis for further extraction of linoleic acid and inokosterone A.

Chemical Reaction and Thermal Diffusion Effects on Mass Transfer Flow through an Inclined Plate

A numerical investigation of boundary layer mass transfer flow through an inclined plate with the effect of chemical reaction and thermal diffusion is presented in this study. The governing partial differential equations (PDE) are transformed to a system of dimensionless non-similar coupled PDEs. The transformed, non-similar conservations equations (momentum balance equation, energy balance equation and concentration balance equation) are then solved using a numerical approach known as explicit finite difference method (EFDM). Basically EFDM introduced for the unsteadiness in the momentum, temperature, and concentration fluid fields is based on the time dependent fluid velocity, temperature and concentration of the boundary surface. During the course of discussion, it is found that the various parameters related to the problem influence the calculated resultant expressions. The computed numerical solution results for the velocity, temperature, and concentration distribution with the effect of various important dimensionless parameters (Grashof number, Modified Grashof number, Prandtl number, Schmidt number, Soret number, Dufour number, chemical reaction parameter and inclination parameter) entering into the problems are critically analyzed and discussed graphically. It can be seen that two physical phenomena chemical reaction and thermal diffusion can greatly effect on the boundary layer fluid flows through an inclined plate.

Intermediate mass dilepton production during the chemical equilibration of quark gluon plasma

The production of dileptons from the chemically equilibrating quark gluon plasma in the intermediate mass region has been studied. Comparing with the calculated results based on the thermodynamic equilibrium system of quark gluon plasma, it has been found that the quark phase of the chemically equilibrating system gives rise to an even larger enhancement of the dileptons production. Therefore, such an enhancement of dilepton production may signal the formation of quark gluon plasma.

Chemical Ionization Mass Spectrometry of Pertrimethylsilylated Desulphoglucosinolates

The chemical ionization mass spectra of ten different glucosinolates isolated from rape seed have been studied. More intense diagnostic ions were identified than in the electron impact mass spectra. The method is suitable for the structure analysis of mixture of glucosinolates.

Uncovering Chemical Interactions between Danshen and Danggui Using Liquid Chromatography–Mass Spectrometry and Network Pharmacology-Based Research on Stroke

Objective: The objective of this study was to decipher chemical interactions between Danshen and Danggui using liquid chromatography–mass spectrometry(LC-MS) and explore the mechanisms of Danshen–Danggui against stroke using network pharmacology and molecular docking. Materials and Methods: First, the chemical compounds of Danshen–Danggui were profiled using ultra-high-performance liquid chromatography(HPLC)-quadrupole time-of-flight MS. Accurately characterized compounds in various proportions of Danshen–Danggui were quantified using HPLC combined with triple quadrupole electrospray tandem MS. Network pharmacology was used to uncover the essential mechanisms of action of Danshen–Danggui against stroke. Discovery Studio Software was used for the molecular docking verification of key active chemicals and stroke-related targets. Results: A total of 53 compounds were characterized, and 22 accurately identified constituents(10 phenolic acids, 8 phthalides, and 4 tanshinones) were quantified in 15 proportions of Danshen–Danggui. The quantification results showed that Danggui significantly increased the dissolution of most phenolic acids(compounds from Danshen), whereas Danshen promoted the dissolution of most phthalides(compounds from Danggui). Overall, the combination of Danshen and Danggui at a 1:1 ratio resulted in the maximum total dissolution rate. Further network pharmacology and molecular docking results indicated that Danshen–Danggui exerted anti-stroke effects mainly by regulating inflammation-related(tumor necrosis factor, hypoxia-inducible factor, and toll-like receptor) signaling pathways, which ranked among the top three pathways based on Kyoto Encyclopedia of Genes and Genomes(KEGG) enrichment analysis. Conclusion: The chemical compounds in Danshen–Danggui could interact with each other to increase the dissolution of the most active compounds, which could provide a solid basis for uncovering the compatibility mechanisms of Danshen–Danggui and Danshen–Danggui-based formulae.