Mass Fraction Of Component Research Articles

Solid–Liquid Equilibrium and Phase Diagram for the Ternary Succinic Acid + Glutaric Acid + Water System

The solid–liquid equilibria (SLE) data of the ternary system succinic acid + glutaric acid + water were measured at the three given temperatures (298.15, 303.15, and 308.15) K using the isothermal solution dissolution equilibrium method, and the densities of equilibrium liquid phase were determined experimentally at the corresponding temperatures. The corresponding isothermal phase diagrams and the diagrams of densities versus mass fraction of component were constructed on the basis of the experimental results. There existed two pure solid phases at (298.15, 303.15 and 308.15) K, including pure succinic acid and pure glutaric acid, which were confirmed and determined by the method of Schreinemaker’s wet residue and X-ray diffraction. The results indicate obviously that there was no solid solution formed in the studied system. The phase diagram at 298.15 K is similar to those at (303.15 and 308.15) K and the crystallization region of glutaric acid is far smaller than that of succinic acid at each temperature. The crystalline fields of succinic acid increase with rising temperature, while crystalline fields of glutaric acid decrease with an increase in temperature.

南京持续雾霾天气中亚微米细颗粒物化学组分及光学性质

A lasting haze pollution event occurred in the Central and East China in January 2013. In this study, Aerodyne Aerosol Chemical Speciation Monitor (ACSM), Photoacoustic Extinctiometer (PAX), and Aethalometer were deployed for real-time and lasting monitoring of non-refractory submicron aerosol (NR-PM1) components (i.e. organics, sulfate, nitrate, ammonium, and chloride), atmospheric aerosol extinction properties, and black carbon (BC) in Nanjing, respectively. During the measuring period, the contribution of PM1 (NR-PM1+BC) species, i.e., organics, nitrate, sulfate, ammonium, chloride, and BC were 32.3%, 26.0%, 17.9%, 13.2%, 2.8%, and 7.8%, respectively. Positive matrix factorization (PMF) analysis indicates that hydrocarbon-like (HOA), semi-volatile oxygenated organic aerosol (SV-OOA), low-volatile oxygenated organic aerosol (LV-OOA) were the major sources for PM1. HOA, SV-OOA, and LV-OOA on average accounted for 27.4%, 32.2%, and 40.4% of organic aerosol, respectively, which means that PM1 consisted mostly of the secondary species. Because of local cooking and traffic emissions, HOA loading dynamically increased at the nighttime, which resulted in a significant variation of organics. Generally, the mass concentrations, the mass fractions of secondary components (i.e. nitrate, sulfate, SV-OOA, and LV-OOA), as well as aerosol signal scattering albedo increased with increasing relative humidity (RH), respectively, implying that the increase in RH was beneficial to the continual formation of secondary aerosol. Furthermore, atmospheric visibility decreased with the increasing of RH and secondary species contents, indicating that there is a synergistic effect between the RH and the secondary species of PM1 on the atmospheric visibility during the haze period.

Dependence of Steady-State Compositional Mixing Degree on Feeding Conditions in Two-Component Aggregation

Two-component aggregative mixing of initially bidisperse particle populations results in a Gaussian-type compositional distribution function, which can be fully described by the overall mass fraction of component A (ϕ) and the mass-normalized power density of excess component A (χ, indicating the mixing degree). χ will reach a steady-state value once the self-preserving size distribution is attained. The relation between the steady-state value of χ (χ∞) and its initial value (χ0) has not been investigated before. This paper applies population balance modeling to gain insight into the dependence of χ∞ on initial feeding conditions. By model fitting from hundreds of systematically varied simulations, it is found that χ∞/χ0, which depends on ϕ, can be formalized by the Gaussian-type function for Brownian aggregation in the free-molecular regime as well as in the continuum regime, however with different geometric standard deviations. The present work can help to optimize mixing by properly selecting the initial mass and number concentrations of components A and B in the feed.

Characterization of submicron aerosols during a month of serious pollution in Beijing, 2013

Abstract. In January 2013, Beijing experienced several serious haze events. To achieve a better understanding of the characteristics, sources and processes of aerosols during this month, an Aerodyne high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS) was deployed at an urban site between 1 January and 1 February 2013 to obtain the size-resolved chemical composition of non-refractory submicron particles (NR-PM1). During this period, the mean measured NR-PM1 mass concentration was 89.3 ± 85.6 μg m−3, and it peaked at 423 μg m−3. Positive matrix factorization (PMF) differentiated the organic aerosol into five components, including a highly oxidized, low-volatility oxygenated organic aerosol (LV-OOA), a less oxidized, semi-volatile oxygenated OA (SV-OOA), a coal combustion OA (CCOA), a cooking-related OA (COA), and a hydrocarbon-like OA (HOA), which on average accounted for 28%, 26%, 15%, 20% and 11% of the total organic mass, respectively. A detailed comparison between the polluted days and unpolluted days found many interesting results. First, the organic fraction was the most important NR-PM1 species during the unpolluted days (58%), while inorganic species were dominant on polluted days (59%). The OA composition also experienced a significant change; it was dominated by primary OA (POA), including COA, HOA and CCOA, on unpolluted days. The contribution of secondary OA (SOA) increased from 35% to 63% between unpolluted and polluted days. Second, meteorological effects played an important role in the heavy pollution in this month and differed significantly between the two types of days. The temperature and relative humidity (RH) were all increased on polluted days and the wind speed and air pressure were decreased. Third, the diurnal variation trend in NR-PM1 species and OA components showed some differences between the two types of days, and the OA was more highly oxidized on polluted days. Fourth, the effects of air masses were significantly different between the two types of days; air was mainly transported from contaminated areas on the polluted days. The comparison also found that the aerosol was more acidic on polluted days. Additionally, the variation trends of the mass concentration and mass fractions of NR-PM1 species and OA components were more dramatic when the NR-PM1 mass loading was at a higher level. The serious pollution observed in this month can be attributed to the synergy of unfavorable meteorological factors, the transport of air masses from high-pollution areas, emission by local sources, and other factors.

Size-resolved aerosol composition and its link to hygroscopicity at a forested site in Colorado

Abstract. Aerosol hygroscopicity describes the ability of a particle to take up water and form a cloud droplet. Modeling studies have shown sensitivity of precipitation-producing cloud systems to the availability of aerosol particles capable of serving as cloud condensation nuclei (CCN), and hygroscopicity is a key parameter controlling the number of available CCN. Continental aerosol is typically assumed to have a representative hygroscopicity parameter, κ, of 0.3; however, in remote locations this value can be lower due to relatively large mass fractions of organic components. To further our understanding of aerosol properties in remote areas, we measured size-resolved aerosol chemical composition and hygroscopicity in a forested, mountainous site in Colorado during the six-week BEACHON-RoMBAS (Bio-hydro-atmosphere interactions of Energy, Aerosols, Carbon, H2O, Organics and Nitrogen–Rocky Mountain Biogenic Aerosol Study) campaign. This campaign followed a year-long measurement period at this site, and results from the intensive campaign shed light on the previously reported seasonal cycle in aerosol hygroscopicity. New particle formation events were observed routinely at this site and nucleation mode composition measurements indicated that the newly formed particles were predominantly organic. These events likely contribute to the dominance of organic species at smaller sizes, where aerosol organic mass fractions were between 70 and 90%. Corresponding aerosol hygroscopicity was observed to be in the range κ = 0.15–0.22, with hygroscopicity increasing with particle size. Aerosol chemical composition measured by an aerosol mass spectrometer and calculated from hygroscopicity measurements agreed very well during the intensive study, with an assumed value of κorg = 0.13 resulting in the best agreement.

Special numerical analysis methods for mathematical models of gas flow in trunkline network

We consider two new methods for numerical solution of a complete system of partial differential equations describing the flow of a gas mixture in pipeline systems. The first method tracks Lagrangian particles as they move together with the flow of transported fluid. When implementing this method, the flow parameters are found by means of a difference scheme, and the distribution of mass fractions of components and enthalpy of matter along the pipeline, by analyzing the motion of the Lagrangian particles. If we ignore the processes of diffusion, these particles must preserve their composition. The energy equation without diffusion and heat conduction reduces to an ordinary differential equation. The method proposed is free of artificial viscosity, because, for example, when considering the equation of continuity of components, variations in their specific mass fractions at any point in space are related only to physically meaningful processes, namely, to the inflow of “new” particles (with “new specific mass fractions of the components). The second method includes constructing spline functions along the space and time coordinates of the computational mesh subject

Thermoelectric composite materials based on intermediate-valence cerium and ytterbium intermetallic compounds

An important thermoelectric characteristic-the power factor of composite thermoelectric materials—is calculated on the basis of performed measurements of the thermopower, electric conductivity, thermal conductivity, and reference data. The investigated composites consist of intermediate-valence CeNi and YbAl3 intermetallic systems and elementary metals, nickel and chromium. On account of the specific transport properties of a heterogeneous medium, it becomes possible to increase the value of the power factor in composites at a sufficiently low concentrations of rare-earth-element-based intermetallic compounds. The dependences of the composite-thermoelectric-material power factor on the temperature and the mass fraction of valence-instable components are obtained.

Quantitative Model of Interactions in the Thermal Decomposition of Key Refuse-Derived Fuel Components

Advanced thermal treatment of refuse-derived fuels (RDFs) necessitates accurate determination of the key component fractions and comprehensive understanding of the decomposition characteristics during thermal conversion. In this paper, the linear weighted sum method is employed to retrieve mass fractions of key components in different municipal solid waste (MSW)-derived fuel pellets through thermogravimetric (TG) analysis. A new Gaussian-fitting-based adjusting model is proposed to quantitatively assess the effect of the interaction on the decomposition of individual components based on differential thermogravimetric (DTG) analysis. Results show that the mass fractions of combustible key components can be determined from DTG curves and by applying the Gaussian-fitting-based adjusting model, the effects of the interaction on the decomposition of polyethylene (PE), polypropylene (PP), polystyrene (PS), polyvinyl chloride (PVC), and cellulose can be identified. It is found that, after mixing PE into RDFs, both the reaction time and activation energy of PE are decreased. The degradation of PVC starts at a higher temperature within the temperature range from 200 to 380 °C, and its reaction time is decreased by 50% within the temperature range from 380 to 500 °C. The activation energy of cellulose is slightly increased. The model proposed in this paper could be a promising method to evaluate the interaction between different key components in mixed samples for optimizing the parameters of the thermal conversion system.

Numerical Simulation of Flotation Circuit for Kakoxene Ore Processing

A group of data from a batch flotation tests were plug into a batch flotation model, and mineral floatability parameters (flotation rate constant, mass fraction of floatability component) were derived from model calculation. Then a flotation circuit of kakoxene ore was designed in JKSimFloat simulator, after inputting those floatability parameters to flotation circuit model, the ultimate grade and recovery of apatite was obtained by analog computation. Meanwhile, the same flotation circuit test was achieved in the laboratory. The apatite grade in concentrate is 66.61% at the recovery of 78.35% by simulation, while apatite grade in concentrate is 72.70% at the recovery of 88.14% in the laboratory tests. Compared with experiment data, the accuracy of simulation is acceptable.

Electroacoustic study of dispersions containing two types of colloidal particles

The procedure of subtraction of electrolyte background electroacoustic signal, which is a standard feature in commercially available instruments, can be used to determine the ζ potentials of particular types of colloidal particles in multi-component dispersions. A preliminary study was carried out in a few two-component dispersions (dispersions containing two types of particles). One-component dispersion with the same mass fraction of component 1 and with the same solution composition as in the two-component dispersion of interest was prepared and the electroacoustic signal of that one-component dispersion was measured and saved as the “electrolyte background”. Then, the signal of the two-component dispersion was measured, and the saved background signal was subtracted from the signal of the two-component dispersion, thus producing the ζ potential of component 2. An analogous procedure was carried out to determine the ζ potential of component 1. Two opposite types of behavior were observed in various two-component dispersions. In certain dispersions (e.g., titania-alumina in dilute solutions of 1–1 electrolytes at various pH), the behavior of the both types particles was independent, that is, their ζ potentials at certain pH in one- and two-component dispersions were equal. In other dispersions (e.g., silica-alumina at neutral pH), the apparent behavior of particles in one- and two-component dispersions was completely different. The observed difference indicates an interaction between the particles, e.g., formation of aggregates containing both types of particles, adsorption of products of dissolution or formation of new phases.

Portable analyzer for rapid analysis of total protein, fat and lactose contents in raw milk measured by non-dispersive short-wave near-infrared spectrometry

A novel portable analyzer for raw milk quality control during the material purchase at dairy plants was developed, by which the percentages(mass fraction) of main components including total protein, fat, and lactose of an unhomogenized milk sample could be determinated in 1 min with the help of non-dispersive short-wave near-infrared (NDSWNIR) spectrometry in a wavelength range from 600 nm to 1100 nm and multivariate calibration. The analyzer was designed with a single-beam optical system, which comprised a temperature control module, a multi-channel narrow-band light source(16 wavelengths), a glass absorption cell with 15 mm sample thickness, a silicon photodiode detector, several compound lenses and a recorder module. A total of 80 raw milk samples were collected at a dairy farm twice a month for 4 months. The samples were scanned with a common UV-Vis-NIR spectrometer and analyzed according to China GB standard methods. The uninformative variables elimination(UVE) method was carried out on the spectrum data and the percentages of main components of all the samples to choose the peak emitting wavelength of each channel of the light source. Another 90 raw milk samples were collected from the same dairy farm thrice a month for 3 months. The samples were analyzed according to China GB standard methods and with the proposed analyzer. The percentages of the main components and the NDSWNIR absorption data of the samples were used for the construction and validation of the multivariate calibration model with partial least squares(PLS) method. The root-mean-square errors of prediction(RMSEP) of total protein, fat and lactose were 0.201, 0.172 and 0.247 and the coefficients of correlation(R) were 0.932, 0.981 and 0.933, respectively.

Polyaromatic hydrocarbons (PAHs) sorption behavior unaffected by the presence of multi-walled carbon nanotubes (MWNTs) in a natural soil system

The batch equilibrium approach was used to examine the influence of multi-walled carbon nanotubes (MWNTs) on the sorption behaviors of polyaromatic hydrocarbons (PAHs) in soil. To the knowledge of the authors, this is the first study of PAH sorption to MWNTs in real natural soil systems. The sorption behavior of three PAHs (naphthalene, fluorene, and phenanthrene) in the presence of commercially available MWNTs in two natural soils (a sandy loam and a silt loam) and Ottawa sand was evaluated. Adsorption of PAHs by MWNTs in this study was three orders of magnitude higher than that of natural soils. Sorption coefficients of PAHs (Kd and Koc) were unchanged in the presence of 2 mg g(-1) MWNTs in soil (p > 0.05). A micro-mechanics approach, termed 'the rule of mixtures' was used for predicting PAH sorption behaviors in mixtures based on sorption coefficients derived from single sorbents. The equation, KT = KMα + KN(1 - α) (K, sorption coefficients, Kd or Koc), predicted sorption coefficients in a mixture based on mixture component sorption coefficients and mass fractions. Data presented in this study could be used to fill data gaps related to the environmental fate of carbon nanotubes in soil.

Vibrational spectra of molecular fluids in nanopores

Coherent anti-Stokes Raman spectroscopy (CARS) is applied for quantitative analysis of carbon dioxide phase composition in pores of nanoporous glass samples at nearcritical temperatures. Measurements of the 1388 1/cm Q-branch were made in a wide pressure range corresponding to coexistence of gas (gas-like), adsorbed and condensed phases within pores. At temperatures several degrees below the critical value, CARS spectra behavior is easy to interpret in terms of thermodynamic model of surface adsorption and capillary condensation. It allows estimating mass fractions of different phase components. Moreover, spectra measured at near critical temperatures 30.5 and 33°C have pronounced inhomogeneous shapes and indicate the presence of condensed phase in the volume of pores. The effect obviously reflects the fluid behaviour near the critical point in nanopores. Pores with smaller radii are filled with condensed phase at lower pressures. The analysis of the CARS spectra is informative for quantitative evaluation of phase composition in nanopores.

Modeling coagulation of externally mixed particles: Sectional approach for both size and chemical composition

Three-dimensional chemical transport models of air quality often assume particles to be internally mixed, that is, particles of a given size are associated to a unique chemical composition. However, measurements show that this assumption is not valid, especially close to sources. We present here the dynamic equation for Brownian coagulation of externally mixed particles (i.e., particles of a given size may have different chemical compositions). Both size distribution and mass fraction of particle chemical components are discretized. Either one or several families of particle chemical components may be discretized to reduce computational cost. The model is validated by comparison to results obtained for internally mixed particles and the effect of mixing is investigated for aerosol mixtures of two, three and four components. Mixing increases with the number of components, because the probability for a particle to coagulate with a particle of different composition increases.

Monoethanolamine and ionic liquid aqueous solutions as effective systems for CO2 capture

AbstractBACKGROUNDIonic liquids are regarded as future effective absorbents of CO2, however high viscosity of this medium limits its use in industry. To resolve the problem a mixture of alkanolamine, ionic liquids and water was proposed as a CO2 absorbent and the influence of solution composition on the volume of CO2 absorbed was determined.RESULTSIn most binary mixtures of ionic liquids and water tasted the presence of water does not affect the overall capacity of absorption mixture except for the 1‐butyl‐3‐methylimidazolium acetate where each mol of water added to the mixture reduces the volume of CO2 that could be absorbed by more than one mole. The capture of CO2 using three‐component systems of water/ionic liquid/monoethanolamine (MEA) was systematically investigated with two selected ionic liquids: 1‐butyl‐3‐methylimidazolium acetate and 1‐ethyl‐3‐methylimidazolium octylsulfate. It was shown that the volume of CO2 absorbed is linearly dependent on the mass fraction of components for 1‐ethyl‐3‐methylimidazolium octylsulfate over the entire experimental domain whereas in 1‐butyl‐3‐methylimidazolium acetate the interaction between ionic liquid and water substantially decreases the volume of CO2 absorbed.CONCLUSIONSThe best results for CO2 absorption were obtained using the three component system 1‐butyl‐3‐methylimidazolium acetate/monoethanolamine/water. Optimization of the composition of an IL‐MEA‐water mixture allows tuning of the properties of the medium. The CO2 absorption capacity of the mixture is mainly a function of MEA concentration and, to a lesser degree, of the concentration of IL possessing chemisorption abilities. The presence of water decreases the viscosity of the mixture and therefore facilitates the application of IL‐based media in industrial applications. © 2012 Society of Chemical Industry

Simulating Pipe Reactor of Biological Growth in Single-Phase Laminar Flow Based on Computational Fluid Dynamics and Reaction Dynamics by OpenFOAM

Pipe reactor simulation of biological growth was investigated based on computational fluid dynamics (CFD) and reaction dynamics in single-phase laminar incompressible flow with the open-source software, OpenFOAM. OpenFOAM supplied a kind of open structure, which made it convenient to add a suitable physical model with CFD equations according to the problem. In order to compute mass transfer and biological growth as a reaction with fluid flow, the component conservation equation was listed with Navier-Stokes equations. With the equations, a pipe reactor was simulated by our solver which was developed based on OpenFOAM. By the simulation, the pressure, velocity and component mass fraction can be obtained at different time and position, which is important to analyze equipments in chemical engineering. Although some details need to be considered such as the definition of reaction term, the boundary conditions, etc., reactor simulation with OpenFOAM has showed very large potential.

Effect of glass composition on activation energy of viscosity in glass-melting-temperature range

In the high-temperature range, where the viscosity (η) of molten glass is <103Pas, the activation energy (B) is virtually independent of temperature (T). Moreover, the coefficient A in the Arrhenius relationship, ln(η)=A+B/T, is nearly independent of melt composition. Hence, the viscosity–composition relationship for η<103Pas is defined by B as a function of composition. Using a database encompassing over 1300 compositions of high-level waste glasses with nearly 7000 viscosity data, we developed mathematical models for B(x), where x is the composition vector in terms of mass fractions of components. In this paper, we present 13 versions of B(x) as first- and second-order polynomials with coefficients for 15 to 39 components, including Others, a component that sums constituents having little effect on viscosity.

The Relationship between Viscosity and Electrical Conductivity of CaF&lt;sub&gt;2&lt;/sub&gt;-SiO&lt;sub&gt;2&lt;/sub&gt;-Al&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt;-CaO-MgO Slag System

The relationship between the viscosity and the electrical conductivity of CaF2-SiO2- Al2O3-CaO-MgO slag system was deduced through theoretical calculation and experiment. The experiment was designed by quadratic orthogonal rotary regression method. The slag viscosity and conductivity were measured at 1600, and the constant (C) was calculated. The calculating model between each component mass fraction and constant C was performed, and the stability of calculating model was also verified by representative slag. The results showed that the calculating constant (C) of regression model is in good agreement with experimental values. Thus, the relationship between refining slag viscosity and conductivity using the formula at certain temperature is feasible.

A quasi-discrete model for droplet heating and evaporation: Application to Diesel and gasoline fuels

The previously suggested quasi-discrete model for heating and evaporation of complex multi-component hydrocarbon fuel droplets is generalised to take into account the dependence of density, viscosity, heat capacity and thermal conductivity of the liquid components on carbon numbers and temperature. This model is applied to the modelling of heating and evaporation of Diesel and gasoline fuel droplets. In agreement with the prediction of the previously reported simplified version of this model in which density, viscosity, heat capacity and thermal conductivity of all liquid components were assumed to be the same as for n-dodecane, it is pointed out that Diesel fuel droplet surface temperatures and radii, predicted by a rigorous model taking into account the effect of all 20 quasi-components, are almost the same as those predicted by the model using five quasi-components. For the Effective Thermal Conductivity/Effective Diffusivity (ETC/ED) model, the number of quasi-components used can be reduced to three. In the case of gasoline fuel, with the maximal number of quasi-components equal to 13, a good approximation for the ETC/ED model can be achieved based on the analysis of just three components. The difference in predictions of the 13 and 1 component models appears to be particularly important when droplets evaporate in gas at a relatively low temperature (450K) and low pressure (0.3MPa). In this case the evaporation time predicted by the one component model is less than half of the time predicted by the 13 component model. The surface mass fraction of the lightest quasi-component in gasoline fuel monotonically decreases with time, while the surface mass fraction of the heaviest component monotonically increases with time. Surface mass fractions of intermediate components initially increase with time, but at later times they rapidly decrease with time.

Computational Mass Transfer Based on CFD with OpenFOAM in Single-Phase Flow

In this work computational mass transfer was investigated based on computational fluid dynamics (CFD) in single-phase flow with the open-source software, OpenFOAM. OpenFOAM supplied a kind of open structure, which made it convenient that a suitable physical model was added with CFD equations according to the problem. In order to compute mass transfer with fluid flow, the component conservation equation was listed with Navier-Stokes equations. With the equations, a pipe flow with mass transfer was simulated on the assumption that the fluid density is constant by our solver which was developed based on OpenFOAM. By the simulation, the pressure, velocity and component mass fraction can be easily obtained at different time and position, which is very important for the analysis of equipments in chemical engineering. Although some details need to be considered such as the change of density with composition, the boundary conditions and the affect of complex shape, computational mass transfer with OpenFOAM has showed very large potential to be applied in industry.