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Binary Mixtures (binary + mixture)
Selected AbstractsTunable Memory Characteristics of Nanostructured, Nonvolatile Charge Trap Memory Devices Based on a Binary Mixture of Metal Nanoparticles as a Charge Trapping Layer,ADVANCED MATERIALS, Issue 2 2009Jang-Sik Lee Tunable memory characteristics are investigated according to the metal-nanoparticle species being used in memory devices. The memory devices are fabricated using diblock copolymer micelles as templates to synthesize nanoparticles of cobalt, gold, and a binary mixture thereof. Programmable memory characteristics show different charging/discharging behaviors according to the storage element configurations as confirmed by nanoscale device characterization. [source] A Contactless Impedance Probe for Simple and Rapid Determination of the Ratio of Liquids with Different Permittivities in Binary MixturesELECTROANALYSIS, Issue 1 2009Franti, ek Opekar Abstract Simple contactless cells with planar or tubular electrodes have been designed for measurement of the permittivity of solutions. The cells, connected to an integrated circuit of astable multivibrator, respond primarily to the capacitance component of the cell impedance, the multivibrator frequency depends in a defined manner on the solution permittivity and is readily used as the analytical signal in determinations of the ratios of components in binary liquid mixtures; water solution of methanol, ethanol and dioxane have been tested. The response of the cell with planar electrodes satisfies well the simple theoretical model and both the cells provide results with a sufficient sensitivity, a low LOD value (units of %vol) and a good precision (around 1%rel). The cell simplicity, small dimensions, long-term stability and the possibility of powering them from a battery make them suitable for hand-held meters. As an example of application in practice, the content of ethanol was determined in the car fuel petrol. [source] Out-of-Equilibrium Self-Assembly of Binary Mixtures of NanoparticlesADVANCED MATERIALS, Issue 5 2006G. Sztrum A coarse-grained lattice-gas model is developed to study the drying-mediated self-assembly of binary mixtures of nanoparticles (NPs). Three model systems are considered, corresponding to equilibrium phase separation between two NPs (A and B), to an amorphous state, and to an ordered, checkerboard-like superstructure (see Figure; red: NPA; green: NPB; blue: solvent). The mechanism for self-ordering depends on the nature of the equilibrium superstructure and on the dynamic coupling to the evaporating solvent. [source] The Morphology and Dynamics of Substrate Effects on Spinodal Decomposition in Binary Mixtures with Short-Range PotentialMACROMOLECULAR THEORY AND SIMULATIONS, Issue 3 2006Li-Tang Yan Abstract Summary: The SDSD of binary mixture with short-range potential is numerically simulated in 3D by cell dynamic system (CDSs), focusing on the phase morphology and dynamics in the parallel cross-sections. The formation mechanism and growth law of the wetting layer are analyzed taking thermal noise effects into account. The simulated results show that the phase inversion in the parallel cross-sections can be observed near the substrate interface. Without thermal noise, the growth law of the wetting layer is simply logarithmic. However, when the strength of thermal noise is large enough, the LS growth law can be found for a short-range surface field. The results demonstrate that thermal noise can increase the extent of phase separation and lead to a transformation between partial and complete wetting for the substrate interface. The evolution of the phase in the parallel cross-sections obeys the LS growth law and is self-similar regardless of the effects of thermal noise. Simulated pattern evolution at different values of z at ,,=,1,000 with G,=,0. [source] Acoustical Properties of Binary Mixtures of Heptane with Ethyl Acetate or Butyl AcetateCHINESE JOURNAL OF CHEMISTRY, Issue 3 2010Divya Shukla Abstract Mixed solvents rather than single pure liquids are of utmost practical importance in chemical and industrial processes as they provide an ample opportunity for the continuous adjustment of desired properties of the medium. Therefore, ultrasonic velocity (u) and density (,) were measured for the binary mixtures formed by heptane with ethyl acetate or butyl acetate at temperatures 293, 298 and 303 K over the entire composition range. Deviation in ultrasonic velocity (,u), deviation in isentropic compressibility (,,s), and excess intermolecular free length (LEf) have been evaluated using the ultrasonic velocity data and the computed results were fitted to the Redlich-Kister polynomial equation. The values of ,u, ,,s and LEf were plotted against the molar fraction of heptane. The observed positive and negative values of excess parameters were discussed in terms of molecular interaction between the components of the mixtures. Experimental values of ultrasonic velocity and density were compared with the results obtained by theoretical estimation procedures. The results were discussed in terms of average absolute deviation (AAD). [source] Effects of ,-Glucan Addition to a Probiotic Containing YogurtJOURNAL OF FOOD SCIENCE, Issue 7 2007T. Vasiljevic ABSTRACT:, This study investigated the effects of addition of ,-glucan from 2 different cereal sources (oat and barley) on growth and metabolic activity of Bifidobacterium animalis ssp. lactis (Bb-12Ô) as determined by plating on a selective medium in yogurt during prolonged cold storage. These yogurt batches were compared to unsupplemented and inulin supplemented controls. All batches were also assessed for syneresis. Oat ,-glucan addition resulted in improved probiotic viability and stability comparable to that of inulin. It also enhanced lactic and propionic acid production. The barley ,-glucan addition suppressed proteolytic activity more than that from oat. These improvements were hindered by greater syneresis caused likely by thermodynamic incompatibility. Small amplitude oscillatory measurements of acidified model mixture of ,-glucan/skim milk solids showed formation of casein gel within the ,-glucan network. Binary mixtures of ,-glucan and skim milk solids had apparent pseudoplastic and non-Newtonian behavior governed mainly by ,-glucan contribution. Above critical concentrations, the mixtures underwent phase separation with the lower phase rich in protein. The phase diagram also showed that the addition of ,-glucan may be possible at or below 0.24 w/w%. [source] The effect of water to ethanol feed ratio on physical properties and aerosolization behavior of spray dried cromolyn sodium particlesJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 5 2005Kambiz Gilani Abstract Cromolyn sodium (CS) was spray dried under constant operation conditions from different water to ethanol feed ratios (50:50,0:100). The spray dried CS samples were characterized for their physicochemical properties including crystallinity, particle size distribution, morphology, density, and water/ethanol content. To determine quantitatively the crystallinity of the powders, an X-ray diffraction (XRD) method was developed using samples with different crystallinity prepared by physical mixing of 100% amorphous and 100% crystalline CS materials. The aerodynamic behavior of the CS samples was determined using an Andersen Cascade Impactor (ACI) with a Spinhaler® at an air flow of 60 L/min. Binary mixtures of each spray dried CS powder and Pharmatose® 325, a commercial ,-lactose monohydrate available for DPI formulations, were prepared and in vitro aerosol deposition of the drug from the mixtures was analyzed using ACI to evaluate the effect of carrier on deposition profiles of the spray dried samples. CS spray dried from absolute ethanol exhibited XRD pattern characteristic for crystalline materials and different from patterns of the other samples. The crystallinity of spray dried CS obtained in the presence of water varied from 0% to 28.37%, depending on the ratio of water to ethanol in the feed suspensions. All samples presented different particle size, water/ethanol content, and bulk density values. CS particles spray dried from absolute ethanol presented uniform elongated shape whereas the other samples consisted mainly of particles with irregular shape. Overall, fine particle fraction increased significantly (p,<,0.01) with decreasing d50% and water and ethanol content of spray dried CS samples. Significant difference (p,<,0.01) in deposition profiles of the drug were observed between corresponding carrier free and carrier blended formulations. The difference in deposition profiles of CS aerosolized from various spray dried samples were described according to the particle size, shape, and water/ethanol contents of the powders. The results of this study indicate that enhanced aerosol performance of CS can be obtained by spray drying of the drug from suspensions containing ,87.5% v/v ethanol. © 2005 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 94:1048,1059, 2005 [source] Ionic Liquids for Propene-Propane SeparationCHEMICAL ENGINEERING & TECHNOLOGY (CET), Issue 1 2010V. Mokrushin Abstract This paper presents an extensive study on the feasibility of ionic liquids (IL) for the extractive distillation of propene-propane mixtures. A new experimental method for express screening of non-volatile entrainers was elaborated. A series of ILs and their mixtures were screened at ambient temperature and low pressures. The screening results show that every tested IL turns a low boiler propene into a high boiler and the alkene-to-alkane separation factor can be as low as 0.28. The solubility and separation efficiency can be tuned by adjusting the chemical structures of the ions forming the IL. It was found that shortening of the alkyl substituents of the imidazolium ions leads to a decrease in capacity and to an increase in the separation factor. Interestingly, ILs containing nitrile functionalities in either the cation or the anion showed, in our experiments, enhanced separation ability combined with still good capacities. From our thermodynamic measurements, [EMIM][[B(CN)4] was proved to be the most promising candidate. Binary mixtures of ILs were also tested and resulted in separation factors and capacities between the values for the individual ILs. For the most promising candidates, also autoclave measurements at elevated temperatures and pressures were carried out. These experiments indicate that the separation ability decreases with growing temperature and loading. In general, our study definitely proves the high potential of ILs to act as entrainers in the extractive distillation of propene-propane mixtures or for the separation of any other low-boiling alkene-alkane mixture. [source] Assessment of acceleration modelling for fluid-filled porous media subjected to dynamic loadingINTERNATIONAL JOURNAL FOR NUMERICAL AND ANALYTICAL METHODS IN GEOMECHANICS, Issue 2 2008B. Lenhof Abstract The purpose of this paper is to examine the importance of different possible simplifying approximations when performing numerical simulations of fluid-filled porous media subjected to dynamic loading. In particular, the relative importance of the various acceleration terms for both the solid and the fluid, especially the convective contribution, is assessed. The porous medium is modelled as a binary mixture of a solid phase, in the sense of a porous skeleton, and a fluid phase that represents both liquid and air in the pores. The solid particles are assumed to be intrinsically incompressible, whereas the fluid is assigned a finite intrinsic compressibility. Finite element (FE) simulations are carried out while assuming material properties and loading conditions representative for a road structure. The results show that, for the range of the material data used in the simulations, omitting the relative acceleration gives differences in the solution of the seepage velocity field, whereas omitting only the convective term does not lead to significant differences. Copyright © 2007 John Wiley & Sons, Ltd. [source] Tunable Memory Characteristics of Nanostructured, Nonvolatile Charge Trap Memory Devices Based on a Binary Mixture of Metal Nanoparticles as a Charge Trapping Layer,ADVANCED MATERIALS, Issue 2 2009Jang-Sik Lee Tunable memory characteristics are investigated according to the metal-nanoparticle species being used in memory devices. The memory devices are fabricated using diblock copolymer micelles as templates to synthesize nanoparticles of cobalt, gold, and a binary mixture thereof. Programmable memory characteristics show different charging/discharging behaviors according to the storage element configurations as confirmed by nanoscale device characterization. [source] Hydrolyzed collagen-based hydrogel with salt and pH-responsiveness propertiesJOURNAL OF APPLIED POLYMER SCIENCE, Issue 4 2007A. Pourjavadi Abstract A novel hydrolyzed collagen-based hydrogel has been prepared by grafting the binary mixture of acrylamide and 2-acrylamido-2-methylpropanesulfonic acid onto the collagen backbone in the presence of a crosslinking agent. Its physicochemical properties in aqueous solution were studied. The effect of reaction variables on both gel content and swelling capacity was investigated to achieve a hydrogel with improved absorbency and gel content. The absorbency under load of optimized hydrogel was also investigated by using an absorbency under load tester at various applied pressures. The swelling ratio in various salt solutions was also determined and additionally, the swelling of hydrogels was measured in solutions with pH ranged 1,13. The synthesized hydrogel exhibited a pH-responsiveness character so that a swelling-collapsing pulsatile behavior was recorded at pH 2 and 8. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007 [source] Supercritical antisolvent micronisation of synthetic all- trans -,-carotene with tetrahydrofuran as solvent and carbon dioxide as antisolventJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 2 2009Miguel A Tavares Cardoso Abstract BACKGROUND: Supercritical antisolvent (SAS) micronisation of synthetic trans -,-carotene was studied using tetrahydrofuran (THF) as solvent and supercritical carbon dioxide (CO2) as antisolvent, with the objective of increasing its bioavailability and facilitating its dispersion in oil and emulsion formulations as a result of its smaller particle size. The micronised powder was analysed by scanning electron microscopy and high-performance liquid chromatography. Micronisation experiments were performed in order to evaluate the effects of temperature (308.15,333.15 K), pressure (6.5,13 MPa) and concentration of the liquid solution (6,9 g L,1). The effect of the supercritical CO2/THF flow ratio in the range between 4 and 44 (on a mass basis) was also analysed. Determinations of equilibrium concentrations of ,-carotene in the CO2/THF mixture were also performed. RESULTS: The particle size obtained ranged from 1 to 500 µm, with mean particle diameters around 100 µm. Three types of morphology were found in the precipitated powder: crystalline with superficial pores and leaf-like appearance; crystalline with regular shapes and blade-like edges; and crystalline without superficial pores and leaf-like apearance. The Peng,Robinson equation of state was used to calculate the density of the CO2/THF binary mixture, and the solubility of ,-carotene in this mixture was correlated with its density. CONCLUSION: The use of the SAS technique to micronise ,-carotene proved to be efficient, and the absence of degradation in the micronised powder allows the industrial application of this technique. Copyright © 2008 Society of Chemical Industry [source] Capacity of activated carbon derived from pistachio shells by H3PO4 in the removal of dyes and phenolicsJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 6 2003Amina A Attia Abstract Two activated carbons were obtained from pistachio shells by impregnation with H3PO4 under standard conditions of acid concentration (50 wt%) and heat treatment at 773 K for 2 h. The soaking time was 24 and 72 h for the two samples before thermal pyrolysis. Analysis of the N2/77 K adsorption isotherms proved that both were highly adsorbing carbons with considerable microporosity, and that the prolonged contact with activant enhanced total porosity (surface area and pore volume) and increased the amount of mesoporosity. Adsorption isotherms of probe molecules, viz methylene blue (MB), rhodamine B (RB), phenol (P) and p -nitrophenol (PNP), were determined at room temperature, from aqueous solutions. Both the Langmuir and Freundlich model adsorption equations show satisfactory fit to experimental data. Both carbons exhibit similar adsorption parameters irrespective of their porosity characteristics. The sequence of uptake per unit weight was: PNP > MB > RB > P. Low affinity towards phenol may be associated with its competition with water molecules which are more favourably attracted to the acid surface which has a high oxygen functionality. Preferred adsorption in the order PNP > MB > RB is proposed to be a function of carbon porosity, related to the increased molecular dimensions of the solutes. Adsorption from a binary mixture of equal concentrations of MB and RB showed reduced uptake for both sorbates in comparison to the single component experiments. RB removal surpasses that of MB in the binary test and may be attributed to lower water solubility and higher molecular dimensions. Copyright © 2003 Society of Chemical Industry [source] Density segregation in vibrated granular beds with bumpy surfacesAICHE JOURNAL, Issue 10 2010Eldin Wee Chuan Lim Abstract Segregation of granular materials by virtue of density or size is a commonly encountered phenomenon in nature. Despite its widespread interest among many researchers in recent years, a complete and unified understanding of granular segregation remains elusive to date. Using molecular dynamics simulations, we report a novel technique of inducing density segregation in a binary mixture of granular materials subjected to vibrations by the use of a bumpy vibrating base. Density segregation in the vertical directions may be induced by oscillating the bumpy base composed of discrete solid particles vertically or horizontally. In both cases, lighter particles tended to rise to the top of the granular bed and form a layer above the heavier particles. We suggest that differences in granular temperature profiles arising from the two different modes of vibrations may play an important role in determining the extent of density segregation occurring in binary granular mixtures. © 2010 American Institute of Chemical Engineers AIChE J, 2010 [source] Gas-phase ion chemistry in the ternary silane,propyne,phosphine systemJOURNAL OF MASS SPECTROMETRY (INCORP BIOLOGICAL MASS SPECTROMETRY), Issue 6 2004Lorenza Operti Abstract The gas-phase ion chemistry of propyne,phosphine and silane,propyne,phosphine mixtures was studied by ion trap mass spectrometry. For the binary mixture, the effect of different partial pressures of the reagents on the yield of C and P-containing ions was evaluated. Reaction sequences and rate constants were determined and reaction efficiencies were calculated from comparison of experimental and collisional rate constants. In the ternary silane,propyne,phosphine systems, the reaction pathways leading to formation of SimCnPpHq+ ions were determined and the rate constants of the most important steps were measured. For some ion species, selected by double isolation procedures (MS/MS), the low ion abundances prevented determination of the reaction rate constants. Si, C and P-containing ions are mainly produced in reactions of SimPpHq+ ions with propyne, while the reactivity of the SimCnHq+ ions towards PH3 and of the CnPpHq+ ions towards SiH4 is very low. The formation of hydrogenated SiCP ions is interesting for their possible role as precursors of amorphous silicon carbides doped with phosphorus, obtained in a single step, by deposition from properly activated silane,propyne,phosphine mixtures. Copyright © 2004 John Wiley & Sons, Ltd. [source] Gas-phase ion chemistry in the ternary SiH4,C3H6,PH3 systemJOURNAL OF MASS SPECTROMETRY (INCORP BIOLOGICAL MASS SPECTROMETRY), Issue 2 2002Stefania Calderan Abstract Propene,phosphine and the silane,propene,phosphine gaseous mixtures were studied by ion trap mass spectrometry. For the binary mixture the variation of ion abundances under different partial pressures and the mechanisms of ion,molecule reactions are reported. Moreover, the rate constants of the main processes were measured and compared with the collisional rate constants to determine the reaction efficiencies. In the ternary silane,propene,phosphine mixture the mechanisms of formation of ion clusters were elucidated, but the complexity of the system and the low abundances of the ions usually isolated by successive steps prevented the determination of rate constants. The hydrogenated ternary ions are mainly formed by reactions of ions with propene, whereas a minor contribution comes from reactions of ions with phosphine. The ions show very low reactivity with silane. The formation processes of these species are discussed in relation to their possible role as precursors of amorphous silicon carbides doped with phosphorus obtained by deposition from properly activated silane,propene,phosphine mixtures. Copyright © 2001 John Wiley & Sons, Ltd. [source] Simulation of binary mixture adsorption of methane and CO2 at supercritical conditions in carbonsAICHE JOURNAL, Issue 3 2006Yohanes Kurniawan Abstract Knowledge of the adsorption behavior of coal-bed gases, mainly under supercritical high-pressure conditions, is important for optimum design of production processes to recover coal-bed methane and to sequester CO2 in coal-beds. Here, we compare the two most rigorous adsorption methods based on the statistical mechanics approach, which are Density Functional Theory (DFT) and Grand Canonical Monte Carlo (GCMC) simulation, for single and binary mixtures of methane and carbon dioxide in slit-shaped pores ranging from around 0.75 to 7.5 nm in width, for pressure up to 300 bar, and temperature range of 308-348 K, as a preliminary study for the CO2 sequestration problem. For single component adsorption, the isotherms generated by DFT, especially for CO2, do not match well with GCMC calculation, and simulation is subsequently pursued here to investigate the binary mixture adsorption. For binary adsorption, upon increase of pressure, the selectivity of carbon dioxide relative to methane in a binary mixture initially increases to a maximum value, and subsequently drops before attaining a constant value at pressures higher than 300 bar. While the selectivity increases with temperature in the initial pressure-sensitive region, the constant high-pressure value is also temperature independent. Optimum selectivity at any temperature is attained at a pressure of 90-100 bar at low bulk mole fraction of CO2, decreasing to approximately 35 bar at high bulk mole fractions. © 2005 American Institute of Chemical Engineers AIChE J, 2006 [source] Equilibrium theory analysis of dual reflux PSA for separation of a binary mixtureAICHE JOURNAL, Issue 10 2004Armin D. Ebner A dual reflux (DR) PSA cycle that combines the features of a conventional (stripping reflux) PSA cycle with those of a new enriching reflux PSA cycle is analyzed to show its potential for separating gas mixtures. On the basis of isothermal equilibrium theory applied to linear isotherms, the ultimate separation is carried out where the binary feed is separated into two pure components with 100% recovery of each component. This very idealized analysis reveals that such a separation is possible over a wide range of conditions, even with pressure ratios as low as 1.1. This analysis also reveals that low throughputs and high heavy component recycle ratios are inherently associated with DR PSA cycles, both of which may be detrimental to the process economics. High throughputs and low heavy product recycle ratios are indeed achievable, but only when using low pressure ratios and less selective adsorbents, both counterintuitive results that make sense when considering the perfect separation is always being achieved. Although these trends may not carry over to actual practice, because the model developed here is overly simplified and invalid under certain conditions, this analysis shows that it may indeed be entirely feasible to separate a binary gas mixture into two relatively pure components with very high recoveries using a DR PSA cycle operating with a very low pressure ratio and, hence, expenditure of energy. © 2004 American Institute of Chemical Engineers AIChE J, 50: 2418,2429, 2004 [source] Vapor,liquid equilibria of mixtures containing alkanes, carbon dioxide, and nitrogenAICHE JOURNAL, Issue 7 2001Jeffrey J. Potoff New force fields for carbon dioxide and nitrogen are introduced that quantitatively reproduce the vapor,liquid equilibria (VLE) of the neat systems and their mixtures with alkanes. In addition to the usual VLE calculations for pure CO2 and N2, calculations of the binary mixtures with propane were used in the force-field development to achieve a good balance between dispersive and electrostatic (quadrupole,quadrupole) interactions. The transferability of the force fields was then assessed from calculations of the VLE for the binary mixtures with n-hexane, the binary mixture of CO2/N2, and the ternary mixture of CO2 /N2/propane. The VLE calculations were carried out using configurational-bias Monte Carlo simulations in either the grand canonical ensemble with histogram,reweighting or in the Gibbs ensemble. [source] Robust design of countercurrent adsorption separation processes: 5.AICHE JOURNAL, Issue 7 2000Nonconstant selectivity Operating conditions for the separation of a binary mixture using a nonadsorbable eluent through simulated moving-bed technology were designed. The results obtained using equilibrium theory for adsorption described by Langmuir models lead to the definition of explicit constraints on the operating parameters to operate the unit in the desired regime of separation. A more general approach was able to produce the same result for a larger class of isotherms. The physical and mathematical conditions defining this larger class of isotherms are discussed, as well as the algorithms necessary to calculate the region of complete separation. Applications to the bi-Langmuir isotherm and the ideal adsorbed solution model, which are more flexible than the Langmuir model and can describe systems where selectivity changes with composition, are discussed. A shortcut method to get an explicit, though approximate, solution is proposed and its accuracy is discussed. [source] Solvent dependent study of carbonyl vibrations of 3-phenoxybenzaldehyde and 4-ethoxybenzaldehyde by Raman spectroscopy and ab initio calculationsJOURNAL OF RAMAN SPECTROSCOPY, Issue 8 2009Veerabahu Ramakrishnan Abstract A Raman spectroscopy investigation of the carbonyl stretching vibrations of 3-phenoxybenzaldehye (3Phbz) and 4-ethoxybenzaldeheyde (4Etob) was carried out in binary mixtures with different polar and nonpolar solvents. The purpose of this study was twofold: firstly, to describe the interaction of the carbonyl groups of two solute molecules in terms of a splitting in the isotropic and anisotropic components and secondly, to analyze their spectroscopic signatures in a binary mixture. Changes in wavenumber position, variation in the anisotropic shift and full width half maximum were investigated for binary mixtures with different mole fractions of the reference systems. In binary mixtures, the observed increase in wavenumber with solvent concentration does not show linearity, indicating the significant role of molecular interactions on the occurrence of breaking of the self-association of the solute. In all the solvents, a gradual decrease in the anisotropic shift reflects the progressive separation of the coupled oscillators with dilution. ,i(,c), 3Phbz,solvent mixtures, exhibit a gradual decrease with decrease in the concentration of the solute which is an evidence on the influence of micro viscosity on linewidth. For 4Etob, the carbonyl stretching vibration shows two well-resolved components in the Raman spectra, attributed to the presence of two distinct carbonyl groups: hydrogen-bonded and free carbonyl groups. The intensity ratio of the carbonyl stretching vibration of these two types of carbonyl groups is studied to understand the dynamics of solute/solvent molecules owing to hydrogen bond interactions. Ab initio calculations were employed for predicting relevant molecular structures in the binary mixtures arising from intermolecular interactions, and are related to the experimental results. Copyright © 2009 John Wiley & Sons, Ltd. [source] STEVIOSIDE AS A REPLACEMENT OF SUCROSE IN PEACH JUICE: SENSORY EVALUATIONJOURNAL OF SENSORY STUDIES, Issue 5 2001GIUSEPPINA PAOLA PARPINELLO ABSTRACT The suitability of stevioside as a sweetener in peach juice was investigated. Comparison between stevioside and sucrose in terms of sweetness, sweet and bitter aftertastes were determined both in water and peach juice. The results demonstrated that 160 mg/L of stevioside may replace 34 g/L of sucrose in juice, with a 25% decrease in calories, without affecting the sensory characteristics of the product. Synergistic and inhibitory effects between sucrose and stevioside were also monitored at different stevioside concentration. A new juice formulation sweetened with a binary mixture of stevioside (160 mg/L) and sucrose (56 g/L) was not significantly different in terms of desirability from a reference product sweetened with 9% sucrose. [source] The Morphology and Dynamics of Substrate Effects on Spinodal Decomposition in Binary Mixtures with Short-Range PotentialMACROMOLECULAR THEORY AND SIMULATIONS, Issue 3 2006Li-Tang Yan Abstract Summary: The SDSD of binary mixture with short-range potential is numerically simulated in 3D by cell dynamic system (CDSs), focusing on the phase morphology and dynamics in the parallel cross-sections. The formation mechanism and growth law of the wetting layer are analyzed taking thermal noise effects into account. The simulated results show that the phase inversion in the parallel cross-sections can be observed near the substrate interface. Without thermal noise, the growth law of the wetting layer is simply logarithmic. However, when the strength of thermal noise is large enough, the LS growth law can be found for a short-range surface field. The results demonstrate that thermal noise can increase the extent of phase separation and lead to a transformation between partial and complete wetting for the substrate interface. The evolution of the phase in the parallel cross-sections obeys the LS growth law and is self-similar regardless of the effects of thermal noise. Simulated pattern evolution at different values of z at ,,=,1,000 with G,=,0. [source] On the hyperbolic system of a mixture of Eulerian fluids: a comparison between single- and multi-temperature modelsMATHEMATICAL METHODS IN THE APPLIED SCIENCES, Issue 7 2007Tommaso Ruggeri Abstract The first rational model of homogeneous mixtures of fluids was proposed by Truesdell in the context of rational thermodynamics. Afterwards, two different theories were developed: one with a single-temperature (ST) field of the mixture and the other one with several temperatures. The two systems are from the mathematical point of view completely different and the relationship between their solutions was not clarified. In this paper, the hyperbolic multi-temperature (MT) system of a mixture of Eulerian fluids will be explained and it will be shown that the corresponding single-temperature differential system is a principal subsystem of the MT one. As a consequence, the subcharacteristic conditions for characteristic speeds hold and this gives an upper-bound esteem for pulse speeds in an ST model. Global behaviour of smooth solutions for large time for both systems will also be discussed through the application of the Shizuta,Kawashima condition. Finally, as an application, the particular case of a binary mixture is considered. Copyright © 2006 John Wiley & Sons, Ltd. [source] Analysis of a Simple Test Device for Tribo-Electric Charging of Bulk PowdersPARTICLE & PARTICLE SYSTEMS CHARACTERIZATION, Issue 1-2 2009upuk Abstract We have developed a simple device to characterise the tribo-electric charging propensity of powders. A sample of around one gram of powder is shaken in a container by reciprocal strokes in a horizontal direction. The electric charge on the powder is quantified by a Faraday cup before and after shaking. In this paper, we analyse the operation of this simple test device by investigating the behaviour of ,-lactose monohydrate (,-LM), hydroxy propyl cellulose (HPC) and a 50 : 50 binary mixture (by mass) of these two powders with various container surfaces commonly used in the pharmaceutical industry. The experiments are carried out in controlled environmental conditions and using different shaking times and frequencies of 10, 20 and 30,Hz. The experimental results show that the saturated charge is independent of the shaking frequency. Furthermore adhered particles coating the inner surface of the shaking container decrease the net amount of charge generated by up to 50,%. [source] Gas-solid Two-phase Mixtures Flowing Upward through a Confined Packed Bed,PARTICLE & PARTICLE SYSTEMS CHARACTERIZATION, Issue 3-4 2006Yurong He Abstract This paper deals with flows of a gas-solid two-phase mixture through a confined packed bed. Both experimental work and numerical modelling are performed on the behaviour of suspended particles within the packed bed. The experimental work is carried out with a non-intrusive Positron Emission Particle Tracking (PEPT) technique, which tracks particle motion at the single particle level for a prolonged period thus allows both the microscopic and macroscopic solids behaviour to be analysed under the steady-state conditions. A continuous based model is used to simulate the flow behaviour. The model uses a newly proposed porosity model and treats the suspended and packed particles as a binary mixture with the packed particles being at zero velocity. The results show that the model captures the main features of solids behaviour in terms of the radial distributions of the suspended particle concentration and the axial solids velocity. Both the experiments and modelling suggest that the wall effect on the motion of suspended particles be limited to a small region close to the wall (,0.5,1 packed particle diameter). However, deviations exist between the model predictions and experiments; more work is therefore proposed to improve the interaction terms in the model between the suspended and packed particles. [source] Micro- and macrorheological properties of polypropylene-polyoxymethylene-copolyamide mixture meltsPOLYMER ENGINEERING & SCIENCE, Issue 6 2001M. V. Tsebrenko The influence of polyoxymethylene (POM) additives on micro- and macrorheological properties of polypropylene-copolyamide (PP/CPA) mixture melts with the PP/CPA ratios of 40/60 and 20/80 wt% was investigated. We have shown that the microrheological processes such as deformation of dispersed polymer droplets and formation of liquid polymer streams, coalescence of these streams along the longitudinal direction, migration, and fracture of the liquid streams into droplets can be controlled by addition of a third component that may interact with CPA in a specific manner. The ternary mixture melt viscosity was greater than that of the binary mixture melt viscosity. The degree of viscosity increase depended upon the composition of the binary mixture, the value of shear stress, and POM content. This dependence may be explained by formation of hydrogen bonds between POM and CPA macromolecules. The addition of POM improved the specific PP fiber formation in the matrix of CPA. The latter is valid even for a composition (PP/CPA ratio is 40/60) close to phase inversion. POM migration toward the walls of the forming die occurred in the flow of the ternary polymer mixture melts. For the purpose of realizing the specific fiber formation during the processing of the above mentioned mixtures we recommend an addition of 5% to 10% of POM. [source] Property-averaging applied to determination of volume contraction in binary-solid liquid-fluidized bedsTHE CANADIAN JOURNAL OF CHEMICAL ENGINEERING, Issue 3 2008Renaud Escudié Abstract This communication examines experimental information from the literature on the volume contraction that can occur when two monocomponent particle species that have a diameter ratio and a buoyancy-corrected density ratio on opposite sides of unity are subjected to liquid fluidization as a binary mixture. Attempts are made to predict this volume contraction by applying monocomponent bed expansion equations using averaged properties of the binary solids. It was found that this method works better if the equations are anchored to experimental monocomponent voidages by the fractional bed volume change that they predict than if the equations are used directly. However, greater prediction accuracy can be achieved by correlation of the adjustable parameter G of the Westman, Am Ceramic Soc, 19, 127,129, (1936) equation, originally applied to binary packed beds. On examine dans cet article des données expérimentales de la littérature scientifique sur la contraction de volume qui peut survenir lorsque deux espèces de particules à composante unique d'un rapport de diamètre et d'un rapport de masse volumique corrigé par la flottabilité plus grands et plus petits que l'unité sont soumises à une fluidisation de liquide comme un mélange binaire. On tente de prédire cette contraction de volume en appliquant des équations d'expansion de lit dans le cas monocomposant et en utilisant les propriétés moyennées des solides binaires. On a trouvé que cette méthode fonctionnait mieux lorsque les équations sont étroitement liées aux degrés de vide monocomposants expérimentaux par le changement de volume de lit factionnaire qu'elles prédisent, que lorsque ces équations sont utilisées directement. Néanmoins, une meilleure précision dans la prédiction peut être obtenue par la corrélation de l'équation du paramètre G ajustable de Westman, Am Ceramic Soc, 19, 127,129, (1936), appliquée originellement aux lits garnis binaires. [source] Layer Inversion and Bed Contraction in Down-Flow Binary-Solid Liquid-Fluidized BedsTHE CANADIAN JOURNAL OF CHEMICAL ENGINEERING, Issue 1 2007R. Escudié Abstract Experiments were carried out on downward-flow water-fluidized binary mixture of spheres selected for possible layer inversion. With the two binaries tested (relatively high-density large particles mixed with lower-density smaller particles), only one of the five possible steps of the layer inversion progression was clearly identified for the higher liquid velocities, a mixed layer being observed at the top of the column close to the distributor. This layer manifested a bed contraction so large that its bulk density was lower than those of its constituent mono-components at the same liquid velocity, which determined its location within the column. The voidage of the mixed layer could be predicted with good accuracy (<0.7%) by regression of the Westman packed bed equation with one adjustable parameter. Des expériences ont été menées sur un mélange binaire fluidisé par de l'eau et à écoulement descendant, comprenant des sphères sélectionnées pour une inversion possible des couches. Avec les deux binaires testées (de grosses particules de masse volumique relativement élevée mélangées à de petites particules de faible masse volumique), seulement une des cinq étapes possibles menant à l'inversion des couches est clairement identifiée pour les vitesses de liquide les plus élevées, une couche mixte étant observée dans la partie supérieure de la colonne près du distributeur. Cette couche montre une contraction du lit si grande que sa masse volumique globale est plus faible que celle de ses composants individuels constitutifs à la même vitesse de liquide, ce qui détermine sa position dans la colonne. Le degré de vide de la couche mixte a pu être prédit avec une bonne précision (<0,7%) en effectuant une régression sur l'équation de lit garni de Westman avec un paramètre ajustable. [source] A bis(amine,carboxylate) copper(II) coordination compound forms a two-dimensional metal,organic framework when crystallized from water and methanolACTA CRYSTALLOGRAPHICA SECTION C, Issue 9 2009Orde Q. Munro When {2,2,-[(2-methyl-2-nitropropane-1,3-diyl)diimino]diacetato}copper(II), [Cu(C8H13N3O6)], (I), was crystallized from a binary mixture of methanol and water, a monoclinic two-dimensional water- and methanol-solvated metal,organic framework (MOF) structure, distinctly different from the known orthorhombic one-dimensional coordination polymer of (I), was isolated, namely catena -poly[[copper(II)-,3 -2,2,-[(2-methyl-2-nitropropane-1,3-diyl)diimino]diacetato] methanol 0.45-solvate 0.55-hydrate], {[Cu(C8H13N3O6)]·0.45CH3OH·0.55H2O}n, (II). The monoclinic structure of (II) comprises centrosymmetric dimers stabilized by a dative covalent Cu2O2 core and intramolecular N,H...O hydrogen bonds. Each dimer is linked to four neighbouring dimers via symmetry-related (opposing) pairs of bridging carboxylate O atoms to generate a `diamondoid' net or two-dimensional coordination network. Tight voids of 166,Å3 are located between these two-dimensional MOF sheets and contain a mixture of water and methanol with fractional occupancies of 0.55 and 0.45, respectively. The two-dimensional MOF sheets have nanometre-scale spacings (11.2,Å) in the crystal structure. Hydrogen-bonding between the methanol/water hydroxy groups and a Cu-bound bridging carboxylate O atom apparently negates thermal desolvation of the structure below 358,K in an uncrushed crystal of (II). [source] | ||||||||||||||||||||||||||||||||||||||||