Viscosity Enhancement Research Articles

Modeling and Precise Prediction of Thermophysical Attributes of Water/EG Blend-Based CNT Nanofluids by NSGA-II Using ANN and RSM

In this study, the thermophysical properties of water–ethylene glycol mixture-based CNT nanofluid (NF) including relative thermal conductivity (TC), viscosity, and specific heat were investigated. These properties were optimized using the NSGA-II method, and the effects of temperature and volume fraction (VF) parameters were investigated on these properties. RSM and MLP methods were used to model these properties. Some correlations are presented in terms of temperature and VF to predict these properties. Convergence coefficients for relative TC, viscosity, and specific capacity are R2 = 0.9893, 0.9665, and 0.9977, respectively. The results showed that the MLP model is better than RSM for this prediction. It was found that the rate of viscosity enhancement reaches up to 3.5 times the amount of base fluid with the addition of nanoparticles (NP). The amount of increase in TC is increased by 17% after the addition of NPs to the base fluid. It was also found that temperature and VF of NPs have a direct effect on relative TC and viscosity. But relative specific heat is only affected by the VF. Both ANN and RSM models predicted the relative specific heat well. But MLP was more accurate in predicting relative viscosity than RSM. Also, both models had a good performance in predicting relative TC in some points. The optimization results were presented with the NSGA-II algorithm for different conditions, and these points do not have priority over each other and all are optimal. It was also found that the VF parameter is much more important than the temperature parameter.

Suppression of viscosity enhancement around a Brownian particle in a near-critical binary fluid mixture

Abstract

The CO2-in-water foam stabilized with the mixture of CO2-soluble surfactant and nonionic surfactant

In recent years, many studies focused on the foam behavior with CO2-soluble surfactants. However, it would be better if the mixing surfactants solution could increase the foam viscosities further and keep the considerable solubility in CO2 comparing with single CO2-soluble surfactant. In this paper, the synergism of the mixture of CO2-soluble surfactant composed of 2 ethoxylated amine headgroups with cocoalkyl tails (C12NEO2) and nonionic surfactant with high degree ethoxylation (C13EO12) was investigated quantitatively by interfacial tension measurement, including micelles in water phase and monolayer at CO2-water interface. Lower critical micelle concentration (CMC) and negative interaction parameters βσ represented the positive synergism clearly after adding nonionic surfactant to the switchable CO2-soluble surfactant. Importantly, the solubility in CO2 and the foam viscosity in porous media were analyzed comparably to confirm the engineering applicability. Even though the C13EO12 is hard to dissolve in CO2 solely, 0.2 wt% surfactants mixture (C13EO12 proportion was lower than 30%) could dissolve in CO2 absolutely to form transparent single-phase at 60 °C and 16 MPa. Limited to the mixture solubility in CO2, which means that the α(C13EO12) <0.3, the optimum surfactants ratio to get the best foam was C12NEO2:C13EO12 = 8:2, where the bulk foam stability and viscosity increased 1.5 and 2.5 times separately. It was attributed to that the positive synergism leaded to more compact surfactants adsorption layers at the interface, then more stable foam. With increasing brine salinity, the enhancement of foam viscosity diminished to a great extent, while the counter ions in brine could help to get more viscous foam stabilized with C12NEO2 alone.

Preparation of stable multiple emulsions using food-grade emulsifiers: evaluating the effects of emulsifier concentration, W/O phase ratio, and emulsification process

In this study, the effects of sodium caseinate (NaCN; emulsifier) concentration, a type of hydrophilic emulsifier, as well as concentration of primary W/O emulsion on the stability of water–oil-water (W/O/W) emulsions were investigated. Emulsions were made using two different emulsification techniques including ultrasonic liquid processing and high pressure homogenization (HPH). Microscopy images of W/O/W emulsions in combination with droplet size analysis and viscosity measurements showed that the sample with a higher percentage of primary W/O emulsion (50 wt% vs. 40 wt% and 25 wt%) was more resistant to coalescence (narrower droplet size distribution and lower creaming index). The higher stability of this emulsion at 50 wt% is due to the enhancement in the solution viscosity which slows down the coalescence and destabilization kinetics. The increase in the NaCN concentration from 0.3 wt% to 0.9 wt% (based on total weight of emulsion) led to formation of larger droplets possibly due to the destabilization of primary W/O emulsion through the disruption of polyglycerol polyricinoleate (PGPR) layer. Regarding the effect of emulsifier type, incorporation of Cremophor EL and Tween 60 in comparison with NaCN resulted in formation of smaller droplet size due to their enhanced surface activity at the interface. Finally, we found that using high pressure homogenizer (HPH) instead of ultrasonic processor was detrimental to the emulsion stability and size distribution. These findings further provide new pathways to design emulsion systems for food and drug delivery applications.

Self-assembly and viscosity changes of binary surfactant solutions: A molecular dynamics study

Hypothesis: Structure and self-assembly of surfactants in the solution shows a fundamental influence on its viscosity. Through molecular simulations using Martini force field, synergistic effects in aggregation as well as the viscosity changes of a binary ionic surfactant system can be modelled.Simulations: Coarse-grained molecular dynamics simulations are performed to model the SDS/CAPB binary surfactant solution, and both equilibrium and non-equilibrium methods are used to calculate the viscosity of the equilibrated micellar systems.Findings: Our simulation results indicate that the new version of the Martini force field can provide more reasonable self-assembly of surfactant, both single and binary system. Synergistic effects in micelle formation for SDS/CAPB have been successfully reproduced, that is, the formation of cylindrical micelles or even wormlike micelles at a lower concentration when compared with the pure system. Meanwhile, both equilibrium and non-equilibrium methods provide quantitatively comparable viscosity for each system. For pure micellar system, the viscosity linearly increases with the total concentration. Nevertheless, our simulation fails to capture the viscosity enhancement of the solution in corresponding with the formation of rodlike or wormlike micelles, and a full parameter optimization of force field is still necessary.

Improving the thermo-physical and rheological properties of crude oil (CO) by the synthesized CuO/SiO2/CaP nanocomposite for drag reduction through horizontal pipelines

The thermo-physical properties and rheological behavior of crude oil (CO) have substantial efficacies on transportation, processing, and refinery operation. SiO2 (silica)–CaP (calcium phosphate)–CuO (copper oxide) nanocomposite was synthesized by the sono-co-precipitation technique. In this work, the impact of nanocomposite volume fraction as well as temperature on the thermo-physical and also rheological characteristics of SiO2–CaP–CuO-based CO nanofluid were evaluated. All experimental tests were done in the temperatures and nanocomposite concentrations of 25–55 °C and 0.05–0.75 vol.%, respectively. Also, the drag reduction of the nanofluid in horizontal pipelines was elucidated by the SiO2–CaP–CuO-based CO nanofluid at 25 °C. The highest dynamic viscosity enhancement was found to be about 44.57% for 0.75 vol.% nanocomposite particles. The nanofluids thermal conductivity augmented with nanocomposite volume fraction increment. The greatest increment in nanofluids thermal conductivity was obtained about 17.26% at 0.75 vol.%. Moreover, four correlations were expanded for the dynamic viscosity and thermo-physical characteristics of the nanofluids with relative average deviation (RAD) percentage of less than 1%, which depended on temperature and nanocomposite volume concentration. The empirical relationships indicated a satisfactory compliance with the laboratory data. Additionally, outcomes demonstrated that the drag reduction of hybrid nanofluid in the horizontal pipeline under fully turbulent flow increased with enhancing the nanofluid concentration. Drag reduction of the nanofluids in the rough pipelines was higher than that in the smooth pipeline at the same Reynolds number in the range of 6500–42,000 and different pipe’s diameter (0.5–1 in.). No considerable increase and/or a reduction in hybrid nanofluid thermal conductivity was found for the recovered nanocomposite in various volume concentrations. The highest dynamic viscosity reduction after three times recovery treatment was obtained about 0.7% for 0.5 vol.% nanocomposite particles.

Stabilization of directly acidified protein drinks by single and mixed hydrocolloids-combining particle size, rheology, tribology, and sensory data.

BackgroundHigh methoxyl pectin and carboxymethylcellulose (CMC) can be used as a stabilizer for directly acidified protein drinks (DAPDs). Use of pectin or CMC together with other polysaccharides and their impacts on product's rheological properties and tribological behavior are still largely unknown. This project investigated the impact of pectin and CMC, alone or in combination with guar gum, locust bean gum (LBG), and gellan gum when preparing DAPDs. The particle size distributions, rheological properties, tribological properties, and sensory properties were determined.ResultsPectin and CMC were dominating in the mixed system with other stabilizers. Increasing the concentration of hydrocolloids resulted in higher viscosity and better lubrication (lower friction coefficient). The sensory viscosity, smoothness, coating, and stickiness intensified as the concentration of hydrocolloids increased. The type and amount of hydrocolloids had a strong effect on the sensorial texture perception, but the flavor perception was only slightly affected.ConclusionUse of combined stabilizers may contribute to providing an effective viscosity enhancement without affecting the flavor in acidified milk beverages.

Properties, heat transfer, energy efficiency and environmental emissions analysis of flat plate solar collector using nanodiamond nanofluids

The collector efficiency, heat transfer, energy, and environmental emissions of water -based nanodiamond (ND) nanofluids circulate in flat plate solar collector (FPSC) has been analyzed experimentally. The analysis was performed at 0.2%, 0.4%, 0.6%, 0.8% and 1.0% particle concentrations, the stability and thermo-physical properties were also analyzed. The thermal conductivity and viscosity enhancements are 22.86% and 79.16% at particle loading of 1.0% against water data at 60 °C. The water and 1.0 vol% of ND/water nanofluids in collector shows efficiencies of 53% and 74%, respectively, which leads to 39.62% enhancement. The collector area was decreased to 28.66% with the use of 1.0 vol% of nanofluid against water data. The collector weight is decreased to 35.81 kg, at 1.0% particle loading, whereas the collector with water weighed 50 kg. The embodied energy of 1.0 vol% of nanofluid is decreased to 1039.51 MJ, whereas, the collector with water its embodied energy is 1451.4 MJ. The CO2 emissions were noticed as 249.98 kg by using 1.0 vol% of nanofluid in FPSC. Additionally, the Nusselt number and heat transfer is augmented to 32.31% and 52.33% at 1.0% vol% with a friction factor penalty of 1.26-times at a Reynolds number of 12,766 against water data. The obtained data is validated with literature and the general form of regression equations was developed in order to evaluate the Nusselt number and friction factor.

High-Performance Hemodialysis Membrane: Influence of Polyethylene Glycol and Polyvinylpyrrolidone in the Polyethersulfone Membrane

the preparation of high-performance hemodialysis membrane, the effect of polyethylene glycol (PEG), polyvinylpyrrolidone (PVP), and also the simultaneous effect of both additives in the polyethersulfone (PES) membrane were investigated. Viscosity measurements demonstrated that PVP has better compatibility with PES, owing to the amorphous nature, closer glassy transition temperature (Tg), and solubility parameters rather than PEG (semi-crystalline and low Tg). This could lead to enhancement in the solution viscosity. SEM results revealed that membranes morphology was dependent upon casting solution viscosity and with increasing viscosity; the formation of macro-voids suppressed and achieving to a membrane with a smaller mean pore size would be possible. The results of the AFM study demonstrated that, with the addition of PVP, membranes with smooth surface were achieved. In contrast, the PEG addition led to a rougher membrane surface. The results verified that PEG had a tangible effect on the permeability of membrane rather than PVP or blend of PVP and PEG, which is owing to its impressive pore-forming role. The maximum pure water permeability (PWP) was achieved for MV4 (24.9 L/m2.h.bar), MG2 (44.8 L/m2.h.bar), MVG2 (25.2 L/m2.h.bar), and MVG3 (25.1 L/m2.h.bar). Rejection test showed that MV3, MV4, MG3, MG4, MVG2, and MVG3 had the best performance in terms of urea removal and maintaining other components, especially bovine serum albumin (BSA). In-vitro cytotoxicity demonstrated the biocompatibility of MV2, MG3, and MVG3 as representative of all membranes. The lactate dehydrogenase (LDH) test confirmed that PVP has a tangible effect on the reduction of platelet adhesion on the membrane surface.

Thermo-associating polymers based on cross-linked 2-acrylamido-methylpropane sulfonic acid, part B: Effect of co-solutes on solution behavior

Thermo-thickening copolymers have gained prominence in technological advancements due to its attractive properties and great potential to overcome the deficiency of viscosity of conventional copolymer upon increasing temperature and salinity. The work in this paper was devoted to examine the aqueous solution viscosity behavior of a new class thermo-thickening copolymer, poly(sodium 2-acrylamido-2-methylpropanesulfonic acid-co-N,N’-methylenebisacrylamide)-g-poly(acrylamide-co-N, N’-diethylacrylamide) denoted as CGBA in the presence of co-solutes. CGBA, which were reported in our previous work manifested notable viscosity enhancement macroscopically above the threshold temperature. However, the effect of small molecules on thermo-associative behavior was still unsettled. Based on structure/properties dependence of CGBA, this work aimed to explore the effect of small molecules and the role of molecular structure on aqueous solution viscosity behavior. The contributions of various added co-solutes such as anionic surfactant, acidic specie, monovalent and divalent salts were considered. For that purpose, three copolymers having distinctive composition of side-arms and length of side-arms were selected and their thermo-associating behaviors were followed by viscosity measurement. Results from rheological tests showed that these co-solutes induced notable modifications in the characteristic of thermo-thickening behavior. For all the co-solutes used, it was observed a strong dependence between the side-arms/water/co-solutes ternary system and the macroscopic property upon heating. Spectrofluorimetric and environmental scanning electron microscope (ESEM) tests were used to gain a deeper insight into the precise mechanism of phase transition process. Results from spectrofluorimetric experiment indicated that, only when the fraction of DEAm in CGBA was higher enough, it would appear strong abrupt macroscopic property above the threshold temperature, which could delay the offset of hydrophobic association phenomenon in the presence of anionic surfactant. Similar effect was also observed in the presence of added acidic specie. Conversely, the addition of monovalent and divalent salts showed dissimilar effects. ESEM revealed that, in comparison with monovalent salt, divalent salt favored the formation of larger and more condensed CGBA skeleton above the threshold temperature which led to an improved macroscopic response. This work demonstrates for the first time the micro-structure changes of copolymer, which was probably the main reason for the changes in magnitude of thermo-thickening effect in different divalent salt dosages.

Experimental study on instability of round nanofluid jets at low velocity

The effects of nano-alumina additives on the instability of round water jets were experimentally studied. The flow visualization inside and near the exit of two transparent nozzles was obtained by high-speed shadow imaging. A spectrum analysis method was applied to determine the surface wavelengths by performing fast Fourier transform on the image grayscale standard deviation data. According to the flow structure inside the sharp-edged nozzle, an integrated model for wavelength prediction was constructed based on the boundary layer instability theory. The effects of the nanoparticle additives on the jet instability were mainly caused by viscosity enhancement and cavitation promotion. The effects were divided into three categories according to the cavitation state in the nozzle. Firstly, for the no-cavitation flow, the nanoparticles exerted a frequency-reduction effect owing to the viscosity increase. Secondly, for the partial cavitation state, the nanoparticles had an increasing-frequency effect owing to the internal cavitation enhancement. Thirdly, for supercavitation or high-speed flow, the dominant frequency no longer changed, whereas the nanoparticles increased the jet instability owing to the enhancements in the external cavitation and aerodynamic force.

Dynamic Viscosity of Purified Multi-Walled Carbon Nanotubes Water and Water-Propylene Glycol-Based Nanofluids

We report in this study the experimental investigation of the dynamic viscosity of purified multi-walled carbon nanotubes (MWCNT) water and water-propylene glycol-based nanofluids in the temperature range 10–80 °C. Four weight concentrations of MWCNTs are considered, between 0.005 and 0.1 wt.%. Triton X-100, a common nonionic surfactant, is used to disperse the nanotubes and stabilize the nanofluids as evidenced by optical characterization. Purified and non-damaged MWCNTs are used for nanofluid preparation by the two-step method. MWCNT characterization is deeply investigated from a set of complementary techniques such as thermogravimetric analysis, transmission electron microscopy, and Raman spectroscopy. The studied nanofluids behave as Newtonian fluids for low nanotube content while a shear-thinning behavior is noticed for higher concentration. Finally, the viscosity enhancement of nanofluids with MWCNT loading is compared to the modified Maron–Pierce model considering the presence of aggregates and their size obtained from optical observations.

A Novel Experimental Study on the Rheological Properties and Thermal Conductivity of Halloysite Nanofluids.

Nanofluids obtained from halloysite and de-ionized water (DI) were prepared by using surfactants and changing pH for heat-transfer applications. The halloysite nanotubes (HNTs) nanofluids were studied for several volume fractions (0.5, 1.0, and 1.5 vol%) and temperatures (20, 30, 40, 50, and 60 °C). The properties of HNTs were studied with a scanning electron microscope (SEM), energy-dispersive X-ray analysis (EDX), Fourier-transform infrared (FT-IR) spectroscopy, X-ray powder diffraction (XRD), Raman spectroscopy and thermogravimetry/differential thermal analysis (TG/DTA). The stability of the nanofluids was proven by zeta potentials measurements and visual observation. With surfactants, the HNT nanofluids had the highest thermal conductivity increment of 18.30% for 1.5 vol% concentration in comparison with the base fluid. The thermal conductivity enhancement of nanofluids containing surfactant was slightly higher than nanofluids with pH = 12. The prepared nanofluids were Newtonian. The viscosity enhancements of the nanofluid were 11% and 12.8% at 30 °C for 0.5% volume concentration with surfactants and at pH = 12, respectively. Empirical correlations of viscosity and thermal conductivity for these nanofluids were proposed for practical applications.

Gelatin tailored pore structure and mechanical properties of freeze-cast porous boron carbide ceramics

The architectures of porous B4C scaffolds play a pivotal role in the performance of their infiltrated composites for multiple applications. Here, we use gelation-freeze-drying approach to creating the porous B4C scaffolds with oriented channels, which are promising and relatively untested freeze-cast constructs. Addition of gelatin alters not only the porosity and shrinkage but also the pore size and morphology of the scaffolds. Specifically, as gelatin contents increase from 0 to 5 wt%, the porosity, closed porosity, and volume shrinkage range from 74.53 to 73.27%, 0.28–0.65% and 1.95–3.96%, respectively; the increased wavelength and lamellar thickness can be attributed to the enhancement in viscosity. Importantly, raised gelatin contents lead to the reduced pore aspect ratio triggering the transformation from lamellae with a high aspect ratio to ellipse shaped morphologies that contribute to the improved compressive strength ranging from 0.7 to 4.4 MPa. The freeze-cast B4C scaffolds with tailored performance by varying gelatin contents widen the application scopes of bioinspired composites.

Gelling hypotonic polymer solution for extended topical drug delivery to the eye.

Eye-drop formulations should hold as high a concentration of soluble drug in contact with ocular epithelium for as long as possible. However, eye tears and frequent blinking limit drug retention on the ocular surface, and gelling drops typically form clumps that blur vision. Here, we describe a gelling hypotonic solution containing a low concentration of a thermosensitive triblock copolymer, for extended ocular drug delivery. On topical application, the hypotonic formulation forms a highly uniform and clear thin layer that conforms to the ocular surface and resists clearance from blinking, significantly increasing the intraocular absorption of hydrophilic and hydrophobic drugs and extending the drug–ocular-epithelium contact time with respect to conventional thermosensitive gelling formulations and commercial eye drops. We also show that the conformal gel layer allows for therapeutically relevant drug delivery to the eyeball’s posterior segment in pigs. Our findings highlight the importance of formulations that conform to the ocular surface prior to viscosity enhancement, for increased and prolonged ocular-surface contact and drug absorption.

Thermal Conductivity and Dynamic Viscosity of Nanofluids: A Review

Thermal conductivity is one of the rheology properties that vital for engineering fluid which indispensable for heat transfer enhancement. For this reason, nanofluid is getting wider attention nowadays due to the presence of nanoparticles in the base fluid can further improve thermal conductivity and dynamic viscosity. These are two important properties for new engineering fluid in providing better cooling and lubricating effects, especially in mechanical and tribology applications. In this paper, specifically, nanofluids thermal conductivity and dynamic viscosity are discussed comprehensively. Both properties’ thermal conductivity and viscosity of nanofluids are improved over the base fluid. Furthermore, these two properties increase when more volume concentrations of nanoparticles are added. In addition, the thermal conductivity also improved with increasing the temperature. From the literature review, the maximum enhancement of thermal conductivity for single nanofluid is recorded 36% of MWCNTs in distilled water. On the other hand, the maximum enhancement of viscosity is recorded 39% of Al2O3 in water-ethylene glycol over base fluid. The hybrid nanofluids that consist of more than one type of nanoparticles exhibit better thermal conductivity where the maximum enhancement is recorded 68% of CuTiO2 in deionized water. For dynamic viscosity measurement, the maximum enhancement of hybrid nanofluids is recorded 168% of MgO-MWCNT in ethylene glycol. Therefore, to sum up, hybrid nanofluids are really promising to enhance heat transfer performance especially for heating and cooling applications. The potential of these nanofluids should be explored extensively to discover its advantages over conventional working fluid.

Efficiency analysis of thermosyphon solar flat plate collector with low mass concentrations of ND–Co3O4 hybrid nanofluids: an experimental study

In the present study, the thermal efficiency, convective heat transfer and friction factor analysis are investigated for a flat plate solar collector with thermosyphon (natural circulation) system using water and nanodiamond–cobalt oxide hybrid nanofluids as the working fluids. The nanodiamond–cobalt oxide hybrid nanoparticles were synthesized using in situ growth and chemical co-precipitation method and characterized using X-ray diffraction, transmission electron microscope and vibrating sample magnetometer. The investigations were performed at different volume flow rates 0.56–1.35 L min−1 and various mass concentrations of 0.05–0.15%. The thermal conductivity and viscosity of nanofluids were measured experimentally at various mass concentrations and temperatures. Due to the augmented thermo-physical properties of hybrid nanofluids, the collector reached higher coefficient of heat transfer as well as improved thermal efficiency than the water data. Maximum thermal conductivity and viscosity enhancements are found to be 15.71% and 45.83% at particle loadings of 0.15% mass concentration and at a temperature of 60 °C. Results show the Nusselt number enhancement of 0.15% mass concentration of hybrid nanofluid is 21.23% with maximum friction factor penalty of 1.13 times against water data. The collector thermal efficiency is found to 59% for the case of 0.15% mass concentration of hybrid nanofluid, where the thermal efficiency of water is 48%. The empirical correlations were developed for Nusselt number and friction factor for collector with hybrid nanofluids within the deviation of ± 3%.

CFD-Based Framework for Analysis of Soil–Pipeline Interaction in Reconsolidating Liquefied Sand

Submarine buried pipelines interact with shallow soil layers that are often loose and prone to fluidization/liquefaction. Such occurrence is a possible consequence of pore pressure build-up induced by hydrodynamic loading, earthquakes, and/or structural vibrations. When liquefaction is triggered in sand, the soil tends to behave as a viscous solid–fluid mixture of negligible shear strength, possibly unable to constrain pipeline movements. Therefore, pipelines may experience excessive displacement, for instance, in the form of vertical flotation or sinking. To date, there are no well-established methods to predict pipe displacement in the event of liquefaction. To fill such a gap, this work proposes a computational fluid dynamics (CFD) framework enriched with soil mechanics principles. It is shown that the interaction between pipe and liquefied sand can be successfully analyzed via one-phase Bingham fluid modeling of the soil. Postliquefaction enhancement of rheological properties, viscosity, and yield stress can also be accounted for by linking soil–pipe CFD simulations to a separate analysis of the pore pressure dissipation. The proposed approach is thoroughly validated against the results of small-scale pipe flotation and pipe dragging tests from the literature.

Nano-scale simulation of oil-water-nanosilica-rock system: Wettability and rheological properties alteration using charged nanoparticles

The real mechanisms beyond the effect of nanoparticles on oil phase displacement by water are still not completely understood. So, in this research, the simultaneous effects of charge and concentration of silica nanoparticles on the oil droplet detachment from calcite surface has been investigated for the first time. For this aim, the parameters of oil droplet contact angle, oil Center Of Mass, Mean Square Displacement and viscosity of water phase have been studied by using molecular dynamics simulation. The thickness of 15°A is selected for all simulations after checking the thickness effect on contact angle results. It was declared that initial shape of oil droplet affected on final contact angle slightly with the relative error of 0.7%. According to the results, silica nanoparticles can lift the oil droplet from the edges because of their interactions with rock surface and water viscosity enhancement which leads to intensify viscous forces and wettability alteration toward more water wet state. In addition, and there is an optimum concentration which decreases with nanoparticle charge rising. In neutral system, the most contact angle alteration occurs in presence of 14 nanoparticles. While the amount of optimum concentration decreased with the growth of nanoparticle's charge and reached to 4 nanoparticles at charge of 0.4 electrons. In addition, there is an optimum charge and it is 0.4e for nanoparticles. The state of rock wettability depends on nanoparticle properties such as charge, size and concentration and this lets us to design a nanoparticle with best performance and least cost.

Application of diluted methanol to allow the production of latex modified asphalt mixture with lower energy consumption

The modification of asphalt mixtures using latex has gained popularity in the asphalt industry as it improves the durability of road pavement. However, the elastomeric properties of latex stiffen the binder, resulting in more energy consumption during the asphalt mixture production. It would consequently cause a higher emission of greenhouse gases, which is undesirable for the human health and environment. This study aims to assess the applicability of diluted methanol as a foaming agent in asphalt mixture incorporating latex produced at a lower temperature. In this study, two designated amounts of diluted methanol (1% and 3% of the weight of asphalt binder) were successively injected with 6% latex into pre-heated asphalt binder at 135 °C in the preparation of foamed binders, while the control and latex modified asphalt mixtures were prepared at 160 °C. Tests of rotational viscosity, expansion rate, and torsional recovery were conducted to study the rheological properties of the mixtures. Service characteristics were evaluated through the indices of workability, compaction energy, and coatability. Moreover, mixture performance tests were carried out to identify the tolerance of the mixtures towards moisture damage, shear force, and permanent deformation. Through the rotational viscosity test, diluted methanol was found to reduce the viscosity of the asphalt binders, which is vital in the production processes at intermediate temperatures. The enhancement in viscosity using 3% diluted methanol had facilitated in higher workability, lower compaction energy, and better aggregate coating, which are the crucial criteria for a better mixing and compaction process. Whereby, a superior foaming quality was exhibited from the 3% diluted methanol application through the assessments of expansion ratio, half-life and foaming index. The moisture and shear resistances of the diluted methanol foamed asphalt mixtures are comparable to the control mixtures even though they were prepared at a lower temperature. Finally, the 3% diluted methanol foamed asphalt mixture promoted a better rutting resistance due to its ability to recover to the initial form which was demonstrated through its torsional recovery.