High Mass Ratio Research Articles

The effects of cyclic alcohols on particle morphology and pore diameter for the SBA-15

The SBA-15 mesoporous particles have been successfully prepared in acid aqueous solution using cyclic alcohols of cyclopentanol (CP) and cyclohexanol (CH) as additives. The effects of cyclic alcohols on the pore diameter and morphology for the SBA-15 are investigated through regulating the mass ratio of additive to surfactant. It is interestingly found that the morphology of the SBA-15 materials gradually transfers from plate-like to rod-shaped with the increase of the mass ratio. Meanwhile, the SBA-15 still maintains the typical 2D p6mm mesostructure even at the high mass ratio of additive to surfactant along with the appearance of enlarged pore size. Furthermore, combined with the evolution of the pore diameter and morphology, a six-step growth mechanism of the SBA-15 particles using cyclic alcohols as additives is firstly proposed. This study would provide the valuable reference and guidance for the preparation of SBA-15.

The evolution of large cavities and disc eccentricity in circumbinary discs

ABSTRACT We study the mutual evolution of the orbital properties of high-mass ratio, circular, co-planar binaries and their surrounding discs, using 3D Smoothed Particle Hydrodynamics simulations. We investigate the evolution of binary and disc eccentricity, cavity structure, and the formation of orbiting azimuthal overdense features in the disc. Even with circular initial conditions, all discs with mass ratios q > 0.05 develop eccentricity. We find that disc eccentricity grows abruptly after a relatively long time-scale (∼400–700 binary orbits), and is associated with a very small increase in the binary eccentricity. When disc eccentricity grows, the cavity semimajor axis reaches values $a_{\rm cav}\approx 3.5\, a_{\rm bin}$. We also find that the disc eccentricity correlates linearly with the cavity size. Viscosity and orbit crossing appear to be responsible for halting the disc eccentricity growth – eccentricity at the cavity edge in the range ecav ∼ 0.05–0.35. Our analysis shows that the current theoretical framework cannot fully explain the origin of these evolutionary features when the binary is almost circular (ebin ≲ 0.01); we speculate about alternative explanations. As previously observed, we find that the disc develops an azimuthal overdense feature in Keplerian motion at the edge of the cavity. A low-contrast overdensity still co-moves with the flow after 2000 binary orbits; such an overdensity can in principle cause significant dust trapping, with important consequences for protoplanetary disc observations.

BVRCIC Observations and Analysis of the UV LEO-type Binary, the Pre-WUMa, V1023 Persei

Abstract V1023 Per is a polar spotted, but well-detached dwarf binary, very likely a Pre-WUMa eclipsing binary. It was observed on 11 nights in 2015 October, November, and December at Dark Sky Observatory in North Carolina with the 0.81 m reflector of Appalachian State University. The period behavior is complex and may be increasing with a cubic or quadratic ephemeris. Its odd light curves are of high amplitude but have no totality and reach maximum light just before and following the secondary eclipse, indicating that it has polar spots similar to UV Leo. The 28 yr orbital period study calls the attention of observers to further monitor this binary to understand the complex nature of the period evolution. Its presently fixed polar spot does indicate that it must have a strong magnetic field and that it is synchronously rotating. The BVR c I c simultaneous 2016 Wilson–Devinney program (W-D) solution gives fillouts of 68% and 75% for the primary and secondary components, respectively. The polar position of the spot, its radius (24°), and T-fact (0.75) indicate that a strong magnetic field is present. The small ΔT in the components (∼289 K) show that the stars are similar in spectral type despite them being well detached. The inclination is high, ∼85.°19 ± 0.°04, but there is not a total eclipse due to the high mass ratio (∼0.739 ± 0.001). Due to the low galactic position (longitude = 150.°390, latitude = −1.°023), its reddening is addressed. The primary components temperature is estimated to be 5250 ± 250 K.

Self-Stratifying Particulate Coating for Robust Superhydrophobic and Latex-Repellent Surface

A technique for preparing superhydrophobic and natural latex-repellent surface requires at least two fabrication components: surface roughness, and surface layer with low free energy. Here, multiscale surface roughness in micro-/nanoscales with low surface energy can be simultaneously achieved through the deposition of fluoroalkyl-functionalized silica aggregates. However, the mechanical durability of such film remains problematic. Therefore, third component such as polymer binder was incorporated carefully to improve adhesion between film-substrate interface without deteriorating surface roughness and surface energy. In this work, we employed self-stratifying coating technique to induce vertical phase separation between particles and polymer during film drying, such that the silica aggregates densely accumulated on the top surface, while polymer binder concentrated near the film bottom. The governing transports during film stratification process involve diffusion and convection driven by evaporation. Thus, this research focused on the effect of drying temperature and evaporation rate on the anti-wetting performance of the coating. The results showed that the liquid-repellent properties of the surface improve with increasing drying temperature, indicating the convection-dominated transport that induced substantial particle trap at the film surface. With polymer binder added, the coatings still showed decent superhydrophobic and natural latex-repellent properties with maximum contact angles 166.4°±0.6° and 157.5°±0.5°, as well as minimum sliding angles 2.7°±0.3° and 2.9°±0.2° for water and natural latex respectively. Also, AFM result revealed that significant surface roughness of 581 ± 18 nm was still achievable even at high blending mass ratio of polymer binder up to half of the silica weight.

FIV induced fatigue damage of two side-by-side flexible cylinders in a uniform flow

Flow-induced vibration (FIV) occurs in deep-water engineering when multiple cylinders interact with each other at a closer range and leads to significant fatigue damages. Nevertheless, many studies have focused on the fatigue damage caused by vortex-induced vibration (VIV). Using a group of flexible cylinders is more common in offshore engineering and has attracted extensive concern; however, the features of FIV fatigue damage remain unclear. In this paper, the experimental data of two side-by-side flexible cylinders with high aspect ratios (length to diameter, L/D = 350, where L is the cylinder length and D is the cylinder diameter) and low mass ratios (total structural mass to displaced fluid mass, m* = 1.90) are utilized to calculate fatigue damages based on S-N curves and Miner's rule. Four spacing ratios (centre-to-centre distance to cylinder diameter, S/D = 3.0, 4.0, 6.0 and 8.0, where S is the centre-to-centre distance) are adopted to investigate their effects on fatigue damage. The results are presented in terms of strain responses, fatigue damage distributions and the maximum fatigue damages. The cross-flow (CF) fatigue damages of the two side-by-side cylinders remain almost consistent with that of the isolated cylinder at most of the reduced velocities, while the in-line (IL) fatigue damages are more than 2 times greater than that of the isolated cylinder when S/D = 3.0 and 4.0. In addition, fatigue damage of the two side-by-side cylinders is more serious than that of the isolated cylinder in the IL direction when S/D = 8.0 owing to considerably vigorous interactions.

Binary Neutron Star Mergers: Testing Ejecta Models for High Mass-Ratios

Neutron stars are extremely dense stellar corpses which sometimes exist in orbiting pairs known as binary neutron star (BNS) systems. The mass ratio (q) of a BNS system is defined as the mass of the heavier neutron star divided by the mass of the lighter neutron star. Over time the neutron stars will inspiral toward one another and produce a merger event. Although rare, these events can be rich sources of observational data due to their many electromagnetic emissions as well as the gravitational waves they produce. The ability to extract physical information from such observations relies heavily on numerical simulations of merger events. In this project, we report results of six simulations for BNS mergers having total system masses of 2.50 or 2.75Msun and with mass ratios of 1.75, 2.00, and 2.25 (the highest mass ratio simulated in the world). Our goals are to (a) test community-developed models of the ejecta produced by BNS mergers, (b) examine the gravitational waveforms for distinctive spectral characteristics, and (c) estimate the electromagnetic emissions of the merger remnants. Simulations are run using the Einstein Toolkit and employ a semirealistic seven-segment piecewise-polytrope model for the neutron stars based on the Skyrme-Lyon equation of state. We find that the community models of ejecta are robust, with some systematic overestimation of the amount of ejecta produced at extremely high mass ratios. Also, several gravitational wave and electromagnetic characteristics are identified, such as reduced gravitational spectral peaks and extended kilonova emissions in the near infrared for weeks after the merger.

Photometric investigation of eight ultra-short period eclipsing binaries from OGLE

We performed a detailed photometric analysis of eight ultra-short period eclipsing binaries (USPEBs) using the Wilson-Devinney method. We present the modeled light curves and derived photometric solutions. The USPEBs with period (P)≤0.21 d considered in our study belong to W-subtype having shallow contact factor (f) <∼20%, high mass ratio (q) >∼0.7 and later spectral types. The absolute parameters for these short-period binaries were derived applying empirical relations. We discuss the evolutionary stage of these USPEBs using the mass-radius, color-density and period-color diagrams. The objects showed poor metallicities, and some objects were even found to be existing around fully convective limits. The period distribution of USPEBs exhibited a sharp cut-off at 0.22 d; however, we observed significant deficits for our objects in the literature. We examined the statistics of USPEBs studied to date (in terms of the distribution of period, mass ratio and component temperatures of USPEBs) and observed that a dominant distribution of component temperatures for these USPEBs was towards lower temperatures.

Sheath Structure in Electronegative Plasma Having Cold Ions: An Impact of Negative Ions’ Mass

A novel concept of the mass ratio of negative to positive ions has been introduced to explore its effect on the sheath structure in three electronegative cold plasmas, namely, CF <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sub> , O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> , and C <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">60</sub> plasmas, for spherical geometry with different probe radii. The magnitudes of velocity of positive ions and potential at the sheath edge are found to modify with the mass ratio, electronegativity, and probe radius. The modification in positive ions' velocity is designated as modified Bohm criterion. Expression is obtained for the sheath thickness, which is found to increase with the higher mass ratios, whereas it reduces with the enhancement in electronegativity and probe radius. No oscillatory structure is observed for the potential profile when the negative ions are described by their fluid equations (as that of the positive ions), instead of their Boltzmann distribution assumed by the other workers. Positive ions' density as a function of distance from the probe for the different mass ratios is also examined.

An Unreasonable Universality of the Thermophoretic Velocity.

Thermophoresis is the migration of dispersed molecules or particles in an inhomogeneous temperature field. It has been associated with various nonequilibrium phenomena ranging from stratified oil reservoirs to prebiotic evolution and the origin of life. The thermophoretic velocity is difficult to predict and appears almost random. We show that, in the case of strongly asymmetric mixtures with high molecular mass ratios of the solute to the solvent, it unexpectedly assumes a universal value once the trivial influence of the viscosity has been factored out. This asymptotic behavior is surprisingly universal and a general property of many highly asymmetric molecular mixtures ranging from organic molecules in n-alkanes to dilute solutions of high polymers. A quantitative explanation is provided on the basis of the asymmetric limit of the pseudoisotopic Soret effect.

Mechanically Robust, Reprocessable Shape Memory Fluorosilicon Materials Using β-H Elimination Reaction and in Situ Interfacial Compatibilization

Recyclable polyvinylidene fluoride/silicone rubber (PVDF/SR) thermoplastic vulcanizates (TPVs) containing high mass ratio of SR (50%) with excellent mechanical performances and shape memory behavio...

Liquid-Phase Aerobic Oxidation of 5-Hydroxymethylfurfural to 2,5-Furandicarboxylic Acid over Co/Mn/Br Catalyst

2,5-Furandicarboxylic acid (FDCA), mainly synthesized by the selective oxidation of 5-hydroxymethylfurfural (HMF), is a biobased monomer for high-performance polymers. In this work, we have a comprehensive investigation on the rapid and highly selective oxidation process of HMF to FDCA in acetic acid (HAc) with Co/Mn/Br catalyst and air as the oxidant. It was found that both aldehyde and hydroxymethyl functional groups of HMF could be first oxidized in the sequential oxidation of HMF to FDCA, but 2,5-diformylfuran (DFF) was the main oxidation intermediate. Apart from the side reaction of HMF overoxidation to COx (CO and CO2) and HMF condensation to polymers, a small part of HMF will be further oxidized to maleic acid (MA) and fumaric acid (FA) via the ring-opening reactions under severe conditions because of the instability of furan ring. To reduce the side reactions and maximize the FDCA yield, the effects of temperature, pressure, substrate solvent ratio, catalyst composition and concentration, and water concentration on the main reactions and side reactions of the HMF oxidation were systematically evaluated. Under the optimum conditions, the selectivity of FDCA reached 92% with the total conversion of HMF in less than 20 min at a high mass ratio of substrate and solvent (1/9), and the purity of FDCA exceeded 99.8%. The experimental results provide a great reference and inspiration for the optimization of the HMF oxidation process and the large-scale production of FDCA.

Seismic effectiveness of hysteretic tuned mass dampers for inelastic structures

The problem of reducing the damage due to seismic loads in engineering structures by means of tuned mass dampers (TMDs) is addressed. Differently from previous studies focused on linear or geometrically nonlinear TMDs, the present work is concerned with a device that exhibits a hysteretic restoring force with pinching. A numerical TMD optimization is carried out so as to ensure optimal energy transfer from the main structure to the TMD for various seismic ground motion severities. The effectiveness of the vibration protection strategy is discussed for two different structural systems, i.e. a multi-story steel building with a purely elastoplastic behavior and a masonry building that exhibits stiffness and strength degradation.Numerical simulations demonstrate that the hysteretic TMD can achieve a meaningful average reduction of the root mean square (RMS) displacement of the steel structure between 40% (for 1% mass ratio) and 60% (for 5% mass ratio). Various seismic records related to soil types and seismic intensity levels different from those considered at the design stage, or unpredictable variations of the main system stiffness up to 10%, are shown to have rather limited influence on the TMD performance. It is shown that a classical linear TMD can attain a protection level comparable to that of the hysteretic TMD only at the expense of much higher mass ratios. Compared to the multi-story structure, the performance of the hysteretic TMD in a masonry building is still satisfactory although degraded, i.e. by about 15% in terms of RMS displacement. The performance is better than that of a classical linear absorber for very small mass ratios, especially for mid- or high-intensity seismic ground motions. The greater robustness of the hysteretic TMD performance for a wide range of seismic ground motions is due to its softening-type backbone, which can be optimized to accommodate the frequency changes that engineering structures typically undergo under seismic excitation. The role of the pinching in the performance of the hysteretic TMD is clarified.

Numerical study of the sound generated by two tandem arranged wings in forward flight

The sound generated by two tandem arranged flexible wings in forward flight is numerically studied by using an immersed boundary method, at a Reynolds number of 100 and Mach number of 0.1. Three distinct cases are studied, encompassing a single wing and two tandem wings flapping in phase and out of phase. The sound generation of flapping wings is systematically studied by varying the wing flexibility (represented by the frequency ratio [Formula: see text]), structure-to-fluid mass ratio ([Formula: see text]), the phase difference (φ), and the gap ([Formula: see text]) between the two flapping wings. The results show that there is a direct correlation between the wing flexibility and sound generation for all cases considered. Specifically, for wings of low mass ratios ([Formula: see text]), an increase in flexibility resulted in a decrease in sound generation. For wings of high mass ratios ([Formula: see text]), an increase in flexibility resulted in higher sound output. The introduction of a second wing flapping in-phase resulted in an increase in aerodynamic features and sound generation, while the introduction of a second wing flapping out-of-phase experiences a decrease in sound output when compared to the in-phase case. In both cases, the effect of the wing flexibility on the sound production is similar to that of the single wing. An increase in flexibility is also found to have an impact on the plane of maximum sound pressure. For example, increasing flexibility resulted in a rotation of the plane of maximum sound pressure counter-clockwise relative to those at lower frequency ratios. Flexible wings with a structure-to-fluid mass ratio of unity and medium flexibility (i.e. [Formula: see text] and [Formula: see text]) are found to generate lower sound with high aerodynamic performance conserved.

First photometric investigation of two short-period eclipsing binaries NSVS 7377756 and for UCAC3 276-106147

We present the first CCD sets of complete light curves for two W Ursae Majoris Systems, UCAC3 276-106147 and NSVS 7377756. These light curves are here analyzed and modelled using the latest version of the Wilson-Devinney Code. We found that UCAC3 276-106147 is a W-subtype shallow-contact eclipsing binary (fill-out factor 7.5%), with a mass ratio of q = 2.88 (1/q = 0.347), a small temperature difference between the components of about ΔT =200K. NSVS 7377756 is an H-subtype binary system with a high mass ratio of q = 1.09 (1/q = 0.947), a weak degree of contact factor f = 3.8% and a temperature difference between the components of ΔT = 398 K. The light curves of both the systems appear to be unspotted. By using our 4 and 7 times of minimum light and the 30 and 104 ToMs extract from the SWASP observations, respectively for UCAC3 276-106147 and NSVS 7377756, the orbital periods are here revised. The elements obtained from this analysis are used to compute the physical parameters of the systems combining our photometric solution with the 3-D correlation obtained for contact binaries by Gazeas (2009). Based on these estimated parameters the evolutionary state of the components of the systems is investigated and discussed.

Experimental investigation of ethanol/diesel dual-fuel combustion in a heavy-duty diesel engine

Ethanol is a promising alternative fuel applicable in the internal combustion engine by virtue of its sustainability and soot-reducing potential. In this study, ethanol is injected into the intake port while diesel is directly injected into the cylinder of a heavy-duty diesel engine enabling dual-fuel operation. The main goals of the study are to probe the ethanol substitution ratio and load range and assess the resulting engine performance and emissions. Tests were performed with the original calibration at several loads using the European Stationary Cycle. The results show that ethanol mass ratios of up to 80% may be reached at low to medium loads without misfire. Addition of ethanol can reduce soot emissions, with no consistent effects on NOx emissions. As the ethanol mass ratio increases, dual-fuel operation suffers from incomplete combustion progressively. Increased HC and CO emissions are, however, believed to be manageable by a diesel oxidation catalyst at high loads. Both combustion and thermal efficiency decrease at low load when ethanol is introduced. However, thermal efficiency at medium load increases from 49.1% to 50%. For medium to high loads, thermal efficiency first increases to 50.7% and 49.7%, respectively, then decreases due to sub-optimal combustion phasing at high ethanol mass ratios. It is noteworthy that the pressure rise rate, ringing intensity, and peak pressure may appear to limit the ethanol ratio to below 40% for medium to high loads. However, this can be mitigated by delaying diesel injection timing, phasing the combustion later, without a large efficiency compromise.

Surrogate model for gravitational wave signals from comparable and large-mass-ratio black hole binaries

Gravitational wave signals from compact astrophysical sources such as those observed by LIGO and Virgo require a high-accuracy, theory-based waveform model for the analysis of the recorded signal. Current inspiral-merger-ringdown models are calibrated only up to moderate mass ratios, thereby limiting their applicability to signals from high-mass ratio binary systems. We present EMRISur1dq1e4, a reduced-order surrogate model for gravitational waveforms of 13,500M in duration and including several harmonic modes for non-spinning black hole binary systems with mass-ratios varying from 3 to 10,000 thus vastly expanding the parameter range beyond the current models. This surrogate model is trained on waveform data generated by point-particle black hole perturbation theory (ppBHPT) both for large mass-ratio and comparable mass-ratio binaries. We observe that the gravitational waveforms generated through a simple application of ppBHPT to the comparable mass-ratio cases agree remarkably (and surprisingly) well with those from full numerical relativity after a rescaling of the ppBHPT's total mass parameter. This observation and the EMRISur1dq1e4 surrogate model will enable data analysis studies in the high-mass ratio regime, including potential intermediate mass-ratio signals from LIGO/Virgo and extreme-mass ratio events of interest to the future space-based observatory LISA.

Investigation of near-contact semi-detached binary WUMi through observations and evolutionary models

W UMi is a near contact, semi-detached, double-lined eclipsing binary star with an orbital period of 1.7 d. Simultaneous analysis of new BV R multi-color light curves and radial velocity data yields the main astrophysical parameters of the binary and its component stars. We determined mass and radius to be M1 = 3.22 ± 0.08 M⊙, R1 = 3.63 ± 0.04 R⊙ for the primary star and M2 = 1.44 ± 0.05 M⊙, R2 = 3.09 ± 0.03 R⊙ for the secondary star. Based on analysis of mid-eclipse times, variation in the orbital period is represented by a cyclic term and a downward parabola. Mass loss from the system is suggested for a secular decrease (−0.02 s yr−1) in the period. Both the mechanisms of a hypothetical tertiary star orbiting around W UMi and the surface magnetic activity of the less massive cooler companion were used to interpret periodic changes. Observational parameters were found to be consistent with binary stellar evolution models produced in the non-conservative approach of MESA at a higher metallicity than the Sun and an age of about 400 Myr for the system. Evidence that the system is rich in metal was obtained from spectral and kinematic analysis as well as evolution models. W UMi, a high mass ratio system compared to classical semi-detached binaries, is an important example since it is estimated from binary evolutionary models that the system may reach its contact phase in a short time interval.

On the eccentricity evolution of massive black hole binaries in stellar backgrounds

ABSTRACT We study the dynamical evolution of eccentric massive black hole binaries (MBHBs) interacting with unbound stars by means of an extensive set of three-body scattering experiments. Compared to previous studies, we extend the investigation down to a MBHB mass ratio of q = m2/m1 = 10−4, where m1 and m2 are the masses of the primary and secondary hole, respectively. Contrary to a simple extrapolation from higher mass ratios, we find that for q ≲ 10−3 the eccentricity growth rate becomes negative, i.e. the binary circularizes as it shrinks. This behaviour is due to the subset of interacting stars captured in metastable counter-rotating orbits; those stars tend to extract angular momentum from the binary, promoting eccentricity growth for q &amp;gt; 10−3, but tend to inject angular momentum into the binary driving it towards circularization for q &amp;lt; 10−3. The physical origin of this behaviour requires a detailed study of the orbits of this subset of stars and is currently under investigation. Our findings might have important consequences for intermediate massive black holes (IMBHs) inspiralling on to MBHs (e.g. a putative $10^3\,\rm M_{\odot }$ black hole inspiralling on to Sgr A*).

Thermo-mechanical stability of axially graded Rayleigh pipes

Thermo-mechanical vibrations of axially functionally graded (AFG) pipes conveying fluid are investigated, aiming at stability enhancement of fluid–interaction systems. Material properties of the pipe vary continuously in the longitudinal direction based on a power-law distribution function. The governing equation of motion of the system was derived using Rayleigh beam theory by considering both linear and nonlinear stress–temperature relations. The Galerkin discretization procedure and eigenvalue analysis were implemented to solve the equation, and stability regions were identified accordingly. The model is validated and compared with the available results in the literature. The influence of material gradient, power index, boundary conditions, rotary inertia factor, temperature rise, and different boundary conditions on the dynamic configuration of the system was elucidated. It was demonstrated that the detached stable regions emerge and develop by increasing the power index at sufficiently high mass ratios. It was shown that either S-shaped or Z-shaped segments may appear on the stability borders. Moreover, the thermal stability map of the supported pipes was also examined, and it was concluded that the AFG power index has a reverse effect on the critical temperature rise of the system at the low and high material gradients. Results of this study may help engineers to design inhomogeneous piping systems optimally. Communicated by Francesco Tornabene.

Fabrication and characterization of emulsions stabilized by tannic acid-wheat starch complexes

Soybean oil-based emulsions stabilized by tannic acid (TA) and wheat starch (WS) complexes were prepared via a simple high-intensity ultrasound emulsification technique. The effects of mass ratio of TA/WS (0.005–0.75) and WS concentration (0.25%, 0.5% and 1.0%) on TA/WS complexes and emulsions were investigated. As the mass ratio increased, TA and WS could gradually form soluble and insoluble complexes, and their hydrophobicity also improved. Consequently, the tendency of the particle size of emulsions to decrease first and then increase appeared with the increasing mass ratio, mainly due to the changes in the contents, size and hydrophobicity of the complex emulsifier. Additionally, the emulsifying capacity of TA/WS complexes improved with increasing concentration of complexes. Moreover, the creaming was inhibited at a high mass ratio or high complex concentration due to the formation of a thick interfacial network around oil droplets or obtention of smaller-sized droplets. Emulsion gel was formed due to TA cross-linked WS on the interface within different oil droplets, and the strength of the gel increased with the mass ratio due to increasing amounts of complexes being absorbed on the interface. When the mass ratio and WS concentration were no less than 0.05 and 0.5%, respectively, emulsions had better oxidative stability. The complexes also had high resistance against droplet coalescence. This study demonstrated that TA/WS complexes could be employed as an emulsifier to improve the oxidative stability of O/W emulsions and that easily oxidized, oil-soluble nutrients or medicines could be protected and delivered through these emulsion systems.