Physical Properties Of Mixtures Research Articles

Investigating influence of mineral filler at asphalt mixture and mastic scales

This study is devoted to understand the mechanisms of mineral fillers in asphalt at the mixture and mastic scales. To do so, the physical properties of asphalt mixtures and mastics were evaluated; in addition, a chemical investigation was presented into the mastic scale for the sake of providing insight into the possible mechanisms between asphalt binder and mineral filler. Three mineral fillers namely hydrated lime (HL), limestone (LS), and cement bypass dust (CD) were incorporated into an asphalt binder at different filler-to-binder (F/B) ratios. For the mechanistic evaluation of the mixtures, the indirect tensile strength (ITS), moisture damage evaluation, resilient modulus, and static creep-recovery tests were carried out. The fracture energies also were quantified for all the studied mixtures. The results of penetration and softening point tests, as well as their pertinent penetration index (PI), were discussed to elucidate some physical properties of the mastics. The nuclear magnetic resonance (NMR) spectroscopy was performed on the mastics to obtain information on molecular structures of the formed composites. The findings of this study emphasize that the physical properties of mixtures and mastics are highly dependent on type and concentration of mineral filler. The 1H NMR and 13C NMR results proved that the inclusion of the studied fillers did not change the molecular structure of the base asphalt binder; hereby the physical mechanisms stand behind the attained properties. It is believed that the findings of this work would contribute to growing knowledge of the mechanisms of mineral fillers in asphalt mixtures.

2D numerical study on flow boiling of zeotropic mixture isobutane/pentane in internal countercurrent flow system

Based on effective diffusion model and volume of fluid (VOF) model, the evaporation process of zeotropic mixture isobutane/pentane in an inclined straight flow channel is investigated. The physical properties of mixture and the source terms in the continuity, momentum, energy and species conservation equations are coded through User Defined Functions (UDF). The simulation results show that the evaporation rate first increases and then decreases from the entrance of vapor to the exit. The interaction of shearing force is relatively stronger at the top and bottom walls than that of near the interface. The velocity boundary layer is similar to the temperature boundary layer. The evaporation rate of pentane is higher than that of isobutane in the unit of kg/s because of its higher molecular weight. In addition, according to available experimental data, another physical model is built to validate the effective diffusion model. The mean absolute percentage error (MAPE) of heat transfer coefficient for all the four cases is 6.9%. This statistical indicator shows that the effective diffusion model proposed by Banerjee can reasonably describe the flow boiling of zeotropic mixture isobutane/pentane.

Caracterización de medios de crecimiento compuestos por corteza de pino y aserrín

En México, la producción de plantas forestales en contenedores rígidos se realiza utilizando principalmente como medio de crecimiento la turba, la vermiculita y la agrolita (6:3:1, mezcla estándar). El aserrín y la corteza de pino son desechos de la industria forestal que pueden ser usados como sustratos. Este trabajo tuvo como objetivo caracterizar cinco mezclas de sustratos, compuestos de corteza, aserrín, turba, vermiculita y agrolita. La evaluación de las mezclas incluyó la caracterización física (densidad aparente, porosidad y curva de retención de humedad) y química (pH, conductividad eléctrica y capacidad de intercambio catiónico). La densidad aparente de las mezclas compuestas de corteza y aserrín varió de 0,31 a 0,51 g cm- 3 y la estándar fue de 0,15 g cm- 3. La porosidad total de 77% a 91% y la estándar fue de 84%. La porosidad de aireación varió de 8% a 20% y la estándar fue de 8%. El agua fácilmente disponible varió de 4,8% a 9,9% y la estándar presentó un valor más elevado (17,7%). El pH de las mezclas compuestas de corteza y aserrín varió de 4,52 a 7,70 y la estándar fue de 3,87. La conductividad eléctrica de 1,84 a 2,69 ds m- 1 y la estándar 1,13 ds m- 1. La capacidad de intercambio catiónico de 43,6 a 89,4 meq/100 g y la estándar 60,4 meq/100 g. La mezcla 4 (20% de corteza + 80% de aserrín) es semejante a la mezcla estándar por sus características físicas, pero no en sus propiedades químicas. Esta mezcla es un sustrato prometedor en la producción de plantas forestales.

Experimental studies on the phase diagram and physical properties of mixture of calamitic and discotic nematic liquid crystals

ABSTRACTPhysical studies on mixture of calamitic and discotic nematic liquid crystals are meagre although they are potential for optimising physical properties. Here, we report experimental studies on the phase diagram and physical properties of mixtures of ambient temperature discotic and calamitic nematic liquid crystals. A substantial decrease in several physical properties such as birefringence, dielectric anisotropy and elastic constants are observed with increasing wt% of discotic compound. On the other hand a large increase in the rotational viscosity is observed. Based on the experimental results a simple model of mutual orientation of the rod-like and disc-like molecules is proposed.

On the Modeling of Steam Methane Reforming

Modeling and simulations of steam methane reforming (SMR) process to produce hydrogen and/or syngas are presented in this article. The reduced computational time with high model validity is the main concern in this study. A volume based reaction model is used, instead of surface based model, with careful estimation of mixture's physical properties. The developed model is validated against the reported experimental data and model accuracy as high as 99.75% is achieved. The model is further used to study the effect of different operating parameters on the steam and methane conversion. General behaviors of the reaction are obtained and discussed. The results showed that increasing the conversion thermodynamic limits with the decrease of the pressure results in a need for long reformers so as to achieve the associated fuel reforming thermodynamics limit. It is also shown that not only increasing the steam to methane molar ratio is favorable for higher methane conversion but the way the ratio is changed also matters to a considerable extent.

Equations of state for mixtures: results from density-functional (DFT) simulations compared to high accuracy validation experiments on Z

We report a computational and validation study of equation of state (EOS) properties of liquid / dense plasma mixtures of Xe and ethane to explore and to illustrate the physics of the molecular scale mixing of light elements with heavy elements. Accurate EOS models are crucial to achieve high-fidelity hydrodynamics simulations of many high-energy density phenomena such as inertial confinement fusion, planet interiors, and planetary impact. While the EOS is often tabulated for separate species, the EOS for arbitrary mixtures is generally not available, requiring properties of the mixture to be approximated by combining physical properties of the pure systems. The main goal of this study is to assess how accurate this approximation is under shock conditions. Density functional theory molecular dynamics (DFT-MD) at elevated-temperature and pressure is used to assess the thermodynamics of the xenon-ethane and xenon-deuterium mixtures. The simulations are unbiased as to elemental species and therefore provide comparable accuracy when describing total energies, pressures, and other physical properties of mixtures as they do for pure systems. In addition, we have performed shock compression experiments using the Sandia Z-accelerator on pure xenon, ethane, and various mixture ratios thereof. The DFT-based simulation results for the principle Hugoniot compare well with the experimental points. The predictions of different EOS mixing models for Xe-D are considered, and we find that a mixing rule based on pressure equilibration performs reliably well.

Mixing of equations of state for xenon-deuterium using density functional theory

We report on a theoretical study of equation of state (EOS) properties of fluid and dense plasma mixtures of xenon and deuterium to explore and illustrate the basic physics of the mixing of a light element with a heavy element. Accurate EOS models are crucial to achieve high-fidelity hydrodynamics simulations of many high-energy-density phenomena, for example inertial confinement fusion and strong shock waves. While the EOS is often tabulated for separate species, the equation of state for arbitrary mixtures is generally not available, requiring properties of the mixture to be approximated by combining physical properties of the pure systems. Density functional theory (DFT) at elevated-temperature is used to assess the thermodynamics of the xenon-deuterium mixture at different mass ratios. The DFT simulations are unbiased as to elemental species and therefore provide comparable accuracy when describing total energies, pressures, and other physical properties of mixtures as they do for pure systems. The study focuses on addressing the accuracy of different mixing rules in the temperature range 1000–40 000 K for pressures between 100 and 600 GPa (1–6 Mbar), thus, including the challenging warm dense matter regime of the phase diagram. We find that a mix rule taking into account pressure equilibration between the two species performs very well over the investigated range.

AN EXPLANATION OF LISIANTHUS AND LETTUCE BEHAVIOR: MICROMORPHOLOGICAL FEATURES AND PHYSICAL PROPERTIES OF DIFFERENT GROWING MEDIA

The micromorphological features and physical properties of several materials for growing media were compared with response variables from two greenhouse experiments, so as to determine the limiting and/or promoting factors of plant development. The first greenhouse experiment used lisianthus (Eustoma grandiflorum) and included organic (coconut fiber, Cf; and peat moss, Pm) and inorganic (pumice, P; and Perlite, Pe) materials, with varying particle size (1-2 and 2-3.36 mm), using the same organic:inorganic ratio (60:40 v/v), and using bulk material as blank tests. The second experiment used lettuce (Lactuca sativa), with one particle size, but with varying ratios (100 Cf, 75:25, 50:50, 25:75, 100 P v/v) of Cf:P mixtures. Thin sections were prepared from the mixtures of both experiments, to describe sorted degree, distribution patterns and porosity (macro and micro). Furthermore, the water release curve was determined (air capacity, AC; easily available water, EAW) for each treatment in both experiments. In lisianthus, it was observed that using a single particle size Cf:P (1-2 or 2-3.36 mm) renders higher yields, because of the loose packing particles, well sorted material and macro- and micropores, resulting in sufficient EAW (36%) and AC (33%). In contrast, the worst effects were in bulk peat moss, because of the poor sorted, close packing particles, and high micropores content (95%) resulting in a low AC (12%) and EAW (49%), overall. Regarding lettuce, the best ratio resulted in Cf:P 75:25 v/v compared to other ratios, because particles presented a banded distribution pattern generating an heterogeneous porous system (vughs, fissures, and simple and compound packing voids). We conclude micromorphology helps to a better understanding of physical properties of mixtures, and to identify which features for growing materials may improve or restrict lisianthus and lettuce development.

Study of Multi-Component Batch Distillation Calculation with Parameters Estimated Using Simple Distillation

The compositions and the physical properties of mixtures are required to simulate multi-component batch distillation operations. In this study, temperature and accumulated distillate are measured as a function of time by use of a simple distillation apparatus. Initial compositions and physical parameters are estimated from this measurement data by a dynamic mathematical model, to examine the extent to which batch distillation operations can be predicted. For an ideal and a non-ideal solution system, the following three types of value estimation are examined: (I) compositions only, (II) parameters of one component, and (III) compositions and parameters of one component. The compositions could be estimated with sufficient accuracy. As for the physical properties, after devising a method for reducing the number of parameters, it is found that a batch distillation operation can be industrially designed from the estimated results.

Drying Behavior of Binary Mixtures of Solids

In this work, a model system zeolite NaY and kaolin (both from Aldrich®), and mixtures (1:4, 2:3, 3:2, 4:1) were studied. True and bulk densities, porosity, and specific surface area were determined for single solids and mixtures. Physical properties of mixtures were calculated from the mixing rule using mass fraction of each solid in the mixture. Calculated and experimental values presented perfect agreement for true density and specific surface area. For bulk density and porosity the mixing rule works well if the volumetric fraction is used, since the mixtures do not follow the mass proportion due to the different particle size distribution. The mixtures present the drying curves between those of the single solids according to their mass proportion. The results show that it is possible to use the mixing rule to evaluate some physical properties as well as the sorption isotherms and drying curves of binary mixtures of solids.

Physical Properties of Flexible Polyurethane “Liquid CO2” Slabstock Foaming Mixtures

In commercial slabstock foaming, liquid CO2 technology is increasingly applied to replace previously used liquid auxiliary blowing agents like CFCs and methylene chloride. Knowledge of physical properties of mixtures which are used in liquidCO2 foaming may contribute to the further development of the liquid CO2 technology. Equations have been determined which do predict, for specific operational conditions and formulations, the pressures which are required in commercial foam operation to keep theCO2 dissolved both in the polyol/CO2 and in the foaming mixture/CO2 solutions. The evident dependence on temperature ofCO2 solubility, established for both polyol and foaming mixtures, strongly supports tight temperature control of the feedstocks in slabstock liquid CO2 foaming. The solubility of CO2 in polyol was found to increase with the EO content of the polyol where the effect of molecular weight was found to be negligible. It was established that small amounts of water and surfactant lower the CO2 solubility, and it is predicted that the commonly used levels of TDI do the same. Based on this information, it is advisable to conduct the mixing of TDI and auxiliary components at pressures a fraction higher than the saturation pressure of the liquid CO2 polyol mixture. A significant decrease of both viscosity and surface tension is quantified for polyol and model foaming systems at increasing liquidCO2 concentration. These decreases may explain why very small cell sizes can be obtained with liquid CO2 foaming, as the nucleation process takes place at high liquid CO2 concentration. The rise in viscosity upon evaporation ofCO2 into the froth may explain the relative stability of the unreacted froth. A cooling capacity of about 1°C per part of CO2 per hundred parts of polyol is determined from two independent experiments. However, for safety reasons, it is advisable to keep the current assumption of 0°C per part of CO2 per hundred parts of polyol in commercial foaming until a further study on the temperature evolution of liquidCO2 blown foaming under practical conditions is conducted.

Thermodynamic and physical properties of mixtures of refrigerants and oils

Thermodynamic and physical properties of mixtures of refrigerants and oils

Studies on the composts for raising seedlings of vegetable crops in hot beds. VII.

In the previous works standard formulas of the composts for raising seedlings of forced vegetables have been proposed. Composts were made of soils (volcanic ash soil, clay soil and fine sand), and organic material (leaf-mold) with optimal fertility. Suitable components differed from sorts of vegetable crops. For cucumbers, the 1 volcanic ash soil-3 leaf-mold mixture (in volume), for tomatoes 2-2 mixture, and for egg-plants 3-1 mixture were most favourable, respectively.The purpose of this study was to determine the physical properties of these composts, and to find the relation between these properties and plant growth.In the first experiment, moisture constants of the mixtures, varying in their proportion of soil and organic material, were determined. From pF-curves of soil water, it was evident that, with increasing proportions of leaf-mold to the soil, macropore spaces were increased markedly. On the other hand, amount of available water were decreased in both volcanic ash soil and clay soil except in fine sand.In the next steps, physical changes in the mixtures which received daily watering at the field for four weeks were observed. The actual volume of solid and liquid phases in each mixture was increased, accompanied with decreasing air capacities, because the sedimentation of the soil particles into macropores occured, and the mixtures became compact considerably during experimental periods. Addition of leaf-mold to the soil was effective for reducing soil compression, though the 3-1 mixture showed more compact than 4-0 component (no leaf-mold added) at the end of experiment.Last of all, the permeabilities of the mixtures to water and to air were measured in the laboratory, after daily watering for four weeks. Both properties indicated similar tendencies, though there were great differences concerning to the soil types. There were noticeable improvements in the water-and air-permeability when leaf-mold was added to the soil. However, just as in the case of the former experiment, 3-1 mixture showed lower rate than other mixtures.It appears from these results that the application. of bulky organic matter to the soil altered remarkably physical characteristics of the composts. And also, it was suggested that their properties may affect on the growth of vegetable seedlings, particularly, on the development of their root. And it was considered that suitable components were determined by mutual relationship between nature of plant root and physical properties of mixtures, and consequently they differed with sorts of vegetable crops.

Properties of Binary Mixtures as a Function of Composition.

D a t a on physical properties of mixtures as a function of composition and temperature are valuable in correlating other properties and in analytical studies. In this and subsequent investigations an attempt w a s made to develop experimental data for a number of systems on which generalized correlations could be developed relating Composition and the property evaluated based on the properties of the pure components, Thus, eight binary systems having a rather wide range of properties (particularly interfacial tension) and in most cases, representing nonideal liquid mixtures were studied. The systems were: 1-propanol-water; toluene-n-octane; water-1-butanol; acetone-1-butanol; benzene-2-chloroethanol; carbon tetrachloride-1-propanol; ethyl alcohol-1,4-dioxane; and methanol-l,4-dioxane. The properties determined were: refractive index vs. composition, liquid density vs. composition and temperature, interfacial tension a t the boiling point and a t 3OoC. as a function of composition, liquid viscosity as a function of temperature and composition, and vapor viscosity a s a function of temperature and composition. Because of the peculiar variation of interfacial tension and viscosity with composition a t the boiling point, no general correlations have been developed. More data on both binary and ternary systems are necessary.

Studies on heterogeneous polymeric systems

AbstractThe physical and morphological properties of heterogeneous mixtures of polystyrene with styrene: butadiene copolymers were determined. A mechanism of ultimate failure is proposed which permits the qualitative rationalization of the effects of copolymer composition, structure, and concentration upon certain physical properties of the mixture.

The Reënforcement of Rubber

Abstract It is a well-known fact that, when mixed in rubber, certain powders reënforce the latter to a considerable extent, whereas others have no effect or only a relatively slight one. Since the nature of the phenomena which take place under these conditions in rubber is far from well established in the present state of knowledge, I have carried out certain experiments of a very simple kind which will by analogy throw some light on the subject. I have found that very important information can be obtained from the study of some physical properties of mixtures of different powders in organic liquids. For a beginning, ordinary paints were tested, but the presence of drying oils complicated matters and it was found advantageous to replace the linseed oil with a non-oxidizing oil, as for example, peanut oil. In this way, pastes of different concentrations were prepared, and the resistance to rupture of the films of these pastes was measured by a method often used to determine the surface tension of liquids. A convenient method of operation is as follows: two thin rods are wet with the paste and are made to adhere to one another. The upper rod A is fastened permanently in a way not shown in Fig. 1. From rod B hangs a pan for small weights which, added in convenient quantity, will finally bring about rupture of the film and separation of the two rods.