The demands for copper and rare earth elements (REEs) in the U.S. will keep rising due to their applications in green energy technologies. Meanwhile, copper production in the U.S. has been declining over the past five years due to the depletion of high-grade ore deposits. The situation for REEs is worse; there is no domestic supply chain of REEs in the U.S. since the demise of Molycorp, Inc. in 2016. Studies have shown that the rejected materials from copper and coal processing plants contain significant amounts of valuable metals. As such, this rejected material can be considered as potential secondary sources for extracting copper and REEs, which may help combat future supply risks for the supply of copper and REEs in the U.S. However, the valuable mineral particles in these resources are ultrafine in size, which poses considerable challenges to the most widely used fine particle beneficiation technique, i.e., froth flotation. A novel technology called the Hydrophobic-Hydrophilic Separation (HHS) process, developed at Virginia Tech, has been successfully applied to recover fine coal in previous research. The results of research into the HHS process showed that the process has no lower particle size limit, similar to solvent extraction. Therefore, the primary objective of this research is to explore the feasibility of using the new process to recover ultrafine particles of coal, copper minerals, and rare earth minerals (REMs) associated with coal byproducts. In the present work, a series of laboratory-scale oil agglomeration and HHS tests have been carried out on coal with the objectives of assisting the HHS tests in pilot-scale, and the scale-up of the process. The knowledge gained from this study was successfully applied to solving the problems encountered in the pilot-scale tests. Additionally, a new and more efficient equipment known as the Morganizer has been designed and constructed to break up the agglomerates in oil phase as a means to remove entrained gangue minerals and water. The effectiveness of the new Morganizers has been demonstrated in laboratory-scale HHS tests, which may potentially result in the reduction of capital costs in commercializing the HHS process. Furthermore, the prospect of using the HHS process for processing high-sulfur coals has been explored. The results of this study showed that the HHS process can be used to increase the production of cleaner coal from waste streams. Application of the HHS process was further extended to recover the micron-sized REMs from a thickener underflow sample from the LW coal preparation plant, Kentucky. The results showed that the HHS process was far superior to the forced-air flotation process. In one test conducted during the earlier stages of the present study, a concentrate assaying 17,590 ppm total REEs was obtained from a 300 ppm feed. In this test, the Morganizer was not used to upgrade the rougher concentrate due to the lack of proper understanding of the fundamental mechanisms involved in converting oil-in-water (o/w) Pickering emulsions to water-in-oil (w/o) Pickering emulsions. Many of the studies has, therefore, been focused on the studies of phase inversion mechanisms. The results showed that phase inversion requires that i) the oil contact angles (θo) of the particles be increased above 90o, ii) the phase volume of oil (ϕo) be increased, and iii) the o/w emulsion be subjected to a high-shear agitation. It has been found that the first criterion can be readily met by using a hydrophobicity-enhancing agent. These findings were applied to produce high-grade REM concentrates from an artificial mixture of micron-sized monazite and silica. Based on the improved understanding of phase inversion, a modified HHS process has been developed to recover ultrafine particles of copper minerals. After successfully demonstrating the efficacy and effectiveness of this process on a series of artificial copper ore samples, the modified HHS process was used to produce high-grade copper concentrates from a series of cleaner scavenger tails obtained from operating plants. / Doctor of Philosophy / Recovery and dewatering of ultrafine particles have been the major challenges in the minerals and coal industries. Based on the thermodynamic advantage that oil droplets form contact angles about twice as large as those obtainable with air bubbles, a novel separation technology called the hydrophobic-hydrophilic separation (HHS) process was developed at Virginia Tech to address this issues. The research into the HHS process previously was only conducted on the recovery of ultrafine coal particles; also, the fundamental aspects of the HHS process were not fully understood, particularly the mechanisms of phase inversion of oil-in-water emulsions to water-in-oil emulsions. As a follow-up to the previous studies, emulsification tests have been conducted using ultrafine silica and chalcopyrite particles as emulsifiers, and the results showed that phase inversion requires high contact angles, high phase volumes, and high-shear agitation. These findings were applied to improve the HHS process for the recovery of ultrafine particles of coal, copper minerals, and rare earth minerals (REMs). The results obtained in the present work show that the HHS process can be used to efficiently recover and dewater fine particles without no lower particle size limits.

This research aims to understand scientific mechanisms of lubrication with molybdenum disulfide (MoS2) solid lubricant coatings in low-viscosity hydrocarbons. A simple and economical spray-deposition of MoS2 is used to coat steel and WC surfaces for testing in simple low-viscosity hydrocarbon liquids across a variety of sliding conditions. Polar (ethanol), and non-polar (dodecane) hydrocarbons were used to study the effects of polarity and affinity for water on MoS2 lubrication mechanisms and tribological behavior. Hexane, decane, and hexadecane were also used to understand the effect of fluid viscosity and hydrocarbon chain length. MoS2/WC/steel duplex coatings were compared to MoS2/steel to investigate the effect of a harder, load supporting base layer on the friction and wear properties of the MoS2 coating. This work highlights the importance of hydrocarbon chemistry on the friction behavior of MoS2, where MoS2 on both WC and steel substrates tested in polar ethanol consistently showed sharp increases in friction coefficient after just a few sliding cycles. This friction increase was attributed to oxidation caused by both adsorption of ethanol molecules to polar components on the MoS2 surfaces, such as edge sites and vacancy sites along the basal plane, causing the MoS2 to readily oxidize and form molybdenum trioxide (MoO3). In contrast, non-polar hydrophobic alkanes, such as dodecane, do not show such deterioration of MoS2 coating, and the friction coefficient remains low throughout the duration of the test, indicating a synergistic effect of the MoS2/alkane solid/liquid lubricating system. Higher chain-length alkanes like hexadecane were found to produce lower friction when lubricating MoS2 than lower-chain length alkanes. Hydrocarbon viscosity was also found to be a factor in determining the friction behavior of MoS2, and friction decreased as viscosity decreased for testing at elevated temperatures. Largest differences in the water contact angle (WCA) were found on MoS2 surfaces exposed to liquid hydrocarbons, where hydrocarbon contamination rendered the MoS2 surface hydrophobic. MoS2/WC duplex coating architecture was found to provide substantially lower wear rates than MoS2/steel when lubricated with both ethanol and dodecane. The effect of contact pressure on the lubrication mechanisms of MoS2/WC coatings was investigated using Raman spectroscopy and MicroXRD, finding that microstructural changes occur inside the wear track, such as decrease in crystallinity and basal plane alignment. The identified mechanisms that occur between low-viscosity hydrocarbons and MoS2 can be used for solid/liquid lubrication systems in fuel-lubricated tribological systems. The results of this work provide a foundation for understanding the tribological properties of MoS2 in polar and non-polar short chain hydrocarbons that previously has not been established, and the obtained knowledge opens new possibilities for wear protection of fuel pump systems designed to operate with low viscosity hydrocarbons.

Boiling is used in a wide variety of industries, including electronics cooling, distillation, and power generation. Fundamental studies on the boiling process are needed for effective implementation. Key performance characteristics of boiling are the heat transfer coefficient, which determines the amount of heat flux that can be dissipated for a given superheat, and critical heat flux(CHF), the failure point that occurs when vapor blankets the surface. The wettability of a surface is one of the key parameters that affects boiling behavior. Wetting surfaces(e.g., hydrophilic surfaces), typically characterized by a static contact angle below 90°,have better critical heat flux due to effective rewetting, but compromised heat transfer coefficients due to increased waiting times between nucleation of each bubble. Meanwhile, nonwetting surfaces (e.g., hydrophobic surfaces), characterized by static contact angles greater than 90°, have better heat transfer coefficients due to improved nucleation characteristic, but reach critical heat flux early due to surface dry out. However, recent studies have shown that the static contact angle alone offers and incomplete, and sometimes inaccurate, description of this behavior, which is instead governed entirely by the dynamic wettability. Specifically, the receding contact angle impacts the size and contact area of bubbles forming on a surface during boiling, while the advancing contact angle determines how the bubble departs. With this more complete set of wettability descriptors, three characteristic wetting regimes define the boiling behavior: hygrophilic surfaces having advancing and receding contact angles both under 90°; hygrophobic surfaces having both these dynamic contact angles over 90°;and ambiphilic surfaces having a receding contact angle less than 90°, but an advancing contact angle greater than 90°.The goal of this thesis is to experimentally characterize and compare the behavior of boiling surfaces in each of these regimes, observe the contact line behavior, and explain the mechanisms for their differences in performance.

Chalcopyrite ore forms the significant fraction of copper deposits in the earth crust. However, it is also the most difficult to treat using conventional ferric leaching methods. Smelting and electro-refining are currently the methods used in treating chalcopyrite concentrate obtained from froth flotation. Due to the ever increasing environmental requirements on smelters by the Environmental Protection Agency, new smelters are scarce in the United States. The scarcity of smelters has led to the urgent need to find a novel leaching method for the abundant chalcopyrite deposits in the USA and the rest of the world. This chapter(one) of the dissertation, therefore, investigated the leaching of chalcopyrite ore at pH 2 using a newly discovered oxidant (peroxodisulfate). Our results show that chalcopyrite leaching using peroxodisulfate follows a surface reaction shrinking core model. The activation energy of chalcopyrite leaching using peroxodisulfate ion was calculated as 41.1 kJ mol⁻¹. We also report that the leaching of chalcopyrite ore is affected by particle size and that stirring hurts leaching of chalcopyrite. Additionally, we found that peroxodisulfate can produce from sulfuric ions electrochemically. Hydrogen peroxide, permanganate, peroxodisulfate and ferric ions are all strong oxidants that have been researched in production pregnant leach solution (PLS) from chalcopyrite ore leaching. Because, solvent extraction is the next step in the recovery of copper from pregnant leach solutions (PLS). The questions, therefore, arises as to the fate of the organic extractant used in solvent extraction coming in contact with strong oxidant residual in the PLS. In chapter two of the dissertation, we studied the effect of strong oxidant residual in PLS on the degradation of organic extractants during solvent extraction of copper. Exposed organic extractants were analyzed using interfacial tension(IFT), Fourier Transform Infrared (FTIR) spectroscopy and CG LS. The results obtained from IFT and FTIR analysis, show no effect on the organic extractants exposed to sunlight and PLS containing the residual strong oxidant. Finally in chapter 3, the dissertation exams alternative water source for the flotation of chalcopyrite. Mineral flotation is a water-intensive process in mining. In order to sustain mining operations such flotation, which rely heavily on water, chapter 3 of the dissertation looks at using alternative water sources (in this case reclaimed wastewater) in the flotation of chalcopyrite ores; this effort is to limit the mining industries dependence on fresh ground water particularly in the Southwest of United States where water is a scarce commodity. The research studied the effect of reclaimed waste water on chalcopyrite flotation via contact angle and surface energy measurements. Furthermore, atomic force microscopy (AFM) and flotation tests were used to supplement the findings from contact angle and surface studies. We conclude here that the contact angle of a pure chalcopyrite surface was determined to be 75.6 degrees. We also found that pure chalcopyrite mineral surface is slightly polar with surface energies γCuFeS2^(LW) = 41.4 mJ/m² (apolar), γCuFeS2^(AB) = 2.9 mJ/m² (polar). The high value of the surface energy indicates pure chalcopyrite surface is slightly hydrophobic.

Shape of a droplet atop a surface heterogeneity at a nanoscale. Small aqueous droplets on homogeneous surfaces, surrounded by a reservoir of vapor are inherently unstable. In contact with supersaturated vapor, the drops will keep growing until they coalesce and form a contiguous aqueous phase. Alternatively, if vapor pressure is below that of the droplets, the droplets gradually evaporate. Departing from this common picture, when nanoscale droplets sit above hydrophilic patches on a heterogeneous surface, at certain conditions they can maintain a stable volume, determined by the pertinent contact angle and the size of the patches. Only the region under the droplet perimeter controls the contact angle, which in turn determines the drops curvature for given volume and the vapor pressure of the liquid in the drop. The drop size may therefore stop changing when its base just covers the hydrophilic patch. The finite range of water-substrate interactions, however, blurs the patch boundaries hence the nanodrop geometry varies with the patch size in a gradual manner. We use molecular simulations to examine this dependence on graphene-like surfaces with topological heterogeneity as complementing studies of chemical heterogeneity (John Ritchie, Master Thesis, VCU, 2010). We measure the microscopic analogue of the contact angle of aqueous nanodrops above circular hydrophilic or hydrophobic patches of varied size. For both the chemically and topographically heterogeneous surfaces, the results confirm the contact angle of a nanodroplet can be predicted by the local Cassie-Baxter mixing relation applied to the area within the interaction range from the drop’s perimeter, which, in turn, enables predictions of condensation and saturated vapor pressure above nanopatterned hydrophilic/hydrophobic surfaces. Switchable nanowetting dynamics. Understanding the dynamic response of contact angle on switchable hydrophobic-hydrophilic surfaces is key to the design of nanofluidic and optical devices. We use molecular dynamics simulation for water droplets with different number of molecules on a molecularly smooth and corrugated substrate. We monitored the relaxation of the droplet geometry in response to a change in surface hydrophobicity. From the time correlation function for the height of the drop’s center of mass we estimate the rates of relaxation for wetting/dewetting processes following the change between hydrophobic and hydrophilic character of the surface. On molecularly smooth surfaces, we find similar forward/backward rates revealing insignificant hysteresis. Calculations on corrugated surfaces, however, reveal quite different relaxation times for forward (Cassie state to Wenzel state) and reverse processes. The observed hysteresis is associated with different friction forces between the droplet and the surface during advancing and receding processes. We calculate the friction coefficient of the corrugated surface for the forward process following the increase in surface hydrophilicity. We compare continuum hydrodynamic (HD) and molecular kinetic theories (MKT) for calculation of the friction coefficient. Although the small size of our system suggests the use of molecular description of the surface, incorporated in MKT, we obtain essentially equal friction coefficients from both theories. This information indicates an overlap between continuum hydrodynamics and molecular dynamics regimes, with both the HD and MKT theories being applicable at the nanoscopic lengthscales we consider. Water dynamics inside nanospheres. Chemical nature of a spherical confinement has significant effect on dynamics of water molecules outside the cage. In a separate study we examined the effect of chemical nature of the cage on the dynamics of water molecules inside the cage. Calculations have been made for variety of time correlation functions of water in four different sizes of spherical hydrophobic/hydrophilic confinements, Cx x=320, 500, 720, 1500 based “hollow buckyballs”, with different spherical pore diameters. Calculated water hydrogen bond lifetimes, diffusion coefficients and rotational relaxation times in these systems reveal a distinctly different water dynamics compared to interfacial water dynamics outside the cage: interestingly we find insignificant changes in time scales for water dynamics in hydrophilic and hydrophobic carbon cages. Even adding partial charges to hydrophilic confinement did not make a big effect on results compared to hydrophobic case. These findings are suggesting that in highly symmetric confinement water molecules do not care about the type of interaction with the wall because of cancellation of forces in different directions.

CONTACT ANGLE OF A NANO-DROP ON A HETEROGENEOUS SURFACE By John Andre Ritchie, Master of Science A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science at Virginia Commonwealth University Virginia Commonwealth University, 2010 Major Director: Dr. Alenka Luzar, Professor of Chemistry We examine the relation between contact angle of a nanodrop of water and the location of surface-water interaction energy at the perimeter and beneath the drop. Young’s equations gives the relationship between surface tension, at the three phase solid liquid vapor interface, and contact angle on a homogeneous surface. Cassie and Baxter generalized this equation to heterogeneous surfaces implying that contact angle corresponds to the average properties of the surface under the drop. McCarthy and coworkers pointed out it is the nature of the substrate at droplet perimeter that controls contact angle. And more recently, McHale in his theoretical derivation applies the Cassie-Baxter equation to the area at the drop’s perimeter. For a nanodrop, the situation is further complicated by the finite range of water-substrate interactions making the definition of the perimeter region somewhat arbitrary. We simulate nanodroplets of water on graphene-like surfaces having hydrophobic and hydrophilic interaction energy at the perimeter and beneath the drop using molecular dynamics. The microscopic analogue of the contact angle was extracted from simulation trajectory data. We confirm the contact angle is exclusively related to the surface interaction energy in the region of the drop’s perimeter. We test the role of finite range of substrate-water interaction when the area of a circular hydrophilic patch beneath the drop’s core is incrementally expanded until the contact angle is equivalent to that on the pure hydrophilic surface. We identify a range of interaction corresponding to a considerable drop in θ when plotting contact angle as a function of patch size. We show the observed contact angle dependence on the size of the patch can be predicted by the Cassie-Baxter mixing relation when limited to the area within the interaction range from the drop’s perimeter.

Orientador: Elaine Maria Cardoso / Resumo: O avanço de novas tecnologias, associado à minimização dos custos de fabricação e instala-ção, constitui um grande desafio para a área de refrigeração, uma vez que a geração de calor tem aumentado gradativamente nos últimos anos. Assim, a busca de novos fluidos com pro-priedades térmicas superiores aos comumente usados tornou-se indispensável para melhorar a eficiência energética. Nas últimas décadas os nanofluidos - dispersões de partículas de escala nanométrica (1 a 100nm) em um fluido-base - têm atraído especial interesse não somente da comunidade acadêmica, mas também da indústria em áreas como: a microeletrônica, microflu-ídica, transporte, manufatura, assistência médica, entre outras. O melhor desempenho térmico e a vasta gama de aplicações fazem dos nanofluidos potenciais substitutos dos refrigerantes utilizados em diversos segmentos da engenharia. Dentro desse contexto, o presente trabalho teve como objetivos: o estudo teórico e experimental da influência das propriedades termofísi-cas e concentração de nanofluidos, bem como, das características geométricas da superfície aquecedora sobre o ângulo de contato e a molhabilidade. Também, atenção foi dada à prepa-ração e caracterização dos nanofluidos (Al2O3-água e Fe2O3-água), por meio da análise expe-rimental da condutividade térmica e da viscosidade dinâmica para diferentes concentrações; uma bancada experimental, para aquisição de imagens de gota séssil, foi construída a fim de viabilizar as análises de ângulo de conta... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The advance of new technologies, associated to the minimization of manufacturing and installation costs, presents a great challenge for the refrigeration area, since the heat generation has increased in recent years. Thus, the search for new fluids with thermal properties higher than those commonly used has become indispensable to improve energy efficiency. In recent decades, nanofluids-dispersions of nanometer-scale particles (1 to 100 nm) in a base fluid - have attracted special interest not only from the academic community but also from industry in areas such as microelectronics, microfluidics, transport, manufacturing, medical assistance, among others. In this context, the present work had the following goals: the theoretical and experimental study of the influence of thermophysical properties and nanofluid concentration, as well as the geometric characteristics of the heating surface on the contact angle and wetta-bility. Attention was also given to the preparation and characterization of nanofluids (Al2O3-water and Fe2O3-water) by the experimental analysis of thermal conductivity and dynamic viscosity for different concentrations; an experimental apparatus for the acquisition of sessile droplet images was designed in order to analyze the contact angle and wettability; and a computational routine was developed to obtain the drop profile and the surface-fluid interaction for the different nanofluids and surfaces used. Based on database, it was possible to evaluate the pre... (Complete abstract click electronic access below) / Doutor

[pt] Em terrenos acidentados é crítico para robôs móveis manter uma adequada tração nas rodas, pois um excessivo deslizamento das mesmas pode fazer o robô capotar ou desviar da rota desejada. Também, se uma força excessiva é aplicada sobre uma região do terreno, pode levar o mesmo a ceder deixando as rodas presas. Para se evitar os problemas acima citados e ainda otimizar o consumo de energia em terrenos planos, a presente dissertação desenvolveu um controle de tração para terrenos acidentados com o intuito de aplicá- lo ao Robô Ambiental Híbrido (RAH) da Petrobrás. O RAH é um robô móvel anfíbio que está em fase de desenvolvimento no Laboratório de Robótica do CENPES (Petrobras), que poderá ser comandado por um operador ou se deslocar autonomamente. Esse robô faz parte do projeto Cognitus, braço tecnológico do projeto Piatam (Potenciais Impactos e Riscos Ambientais da Indústria de Óleo e Gás na Amazônia), e será aplicado na monitoração e coleta de dados do meio ambiente de dois gasodutos da Petrobrás na região Amazônica, o gasoduto Urucu (AM)- Porto Velho (RO) e o gasoduto Coari (AM) - Manaus (AM). A técnica de controle de tração de veículos robóticos em terrenos acidentados desenvolvida visa controlar a velocidade ao mesmo tempo em que garante a estabilidade dinâmica, não deslizamento das rodas, evita a saturação dos motores, e em certas condições ainda permite minimizar a potência requerida através do conhecimento dos ângulos de contato entre as rodas e o terreno. Foram feitas duas modelagens independentes, uma considerando a suspensão do robô flexível e a outra considerando o veículo robótico como um corpo rígido, sendo ambas para o caso plano (2D).Foram realizadas simulações em terrenos suaves e acidentados, as quais comprovaram a eficácia das técnicas de controle propostas. / [en] Abstract Silva, Alexandre F. Barral Silva; Meggiolaro, Marco Antonio. Traction Control to Mobile Robotic Systems in Rough Terrain. Rio de Janeiro, 2004. 194 p. MSc. Thesis - Departamento de Engenharia Mecânica, Pontifícia Universidade Católica do Rio de Janeiro. In rough terrain it is critical for mobile robots to maintain adequate wheel traction, because excessive sliding could cause the robot to roll over or deviate from its intended path. Also, if an excessive force is applied onto the terrain, the soil may fail and trap the robot wheels. To avoid these problems, and also minimize the power consumption on even terrain, the present work develops a rough terrain traction control to be applied to the Hybrid Environmental Robot (HER) from Petrobras. The HER is an amphibious mobile robot developed by the Robotics Laboratory from CENPES (Petrobras). It can be commanded by an operator or autonomously. This robot is part of the Cognitus Project, technological branch of the Piatam project (Potential Impacts and Environmental Risks of the Oil and Gas Industry in the Amazon). It will be used for monitoring and environmental data collecting along two gas pipelines in the Amazon region, the Urucu (AM) - Porto Velho (RO) and the Coari (AM) - Manaus (AM). The developed traction control of robotic vehicles in rough terrain aims to control the speed at the same time that it guarantees dynamic stability, no slip of the wheels, prevents motor saturation, and under certain conditions it may also allow for the minimization of the required power. This control needs the knowledge of the current state of the robot, including the contact angles between its wheels and the terrain. Two independent 2D models have been proposed, one including the suspension compliance and one considering the robotic vehicle as a rigid body. Simulations have been performed in even and rough terrains, proving the effectiveness of the proposed control techniques.

Este trabalho trata da caracterização de propriedades termodinâmicas e de transporte de nanofluidos baseados em nanopartículas de alumina em água para diferentes concentrações. Suspensões estáveis foram elaboradas por meio de um agitador ultrassônico. As seguintes propriedades foram analisadas: i) condutividade térmica com o método da sonda-linear; ii) viscosidade dinâmica através do reômetro do tipo cone e placa e iii) ângulo de contato com base em registros fotográficos de gotas em uma superfície plana e o tratamento de imagem através de um programa elaborado em LabVIEW. Procedimentos foram utilizados visando validar os métodos experimentais adotados, entre eles a comparação com resultados para fluidos puros. Além do estudo experimental, foi realizada uma análise crítica da literatura sobre condutividade térmica e viscosidade dinâmica de nanofluidos. Com base nesta análise, os resultados experimentais foram comparados a dados empíricos da literatura e métodos de previsão de propriedades desenvolvidos para nanofluidos e para suspensões de particulado sólido em líquido. De uma maneira geral, os resultados levantados neste estudo para condutividade térmica e viscosidade dinâmica de nanofluidos foram significativamente superiores a maioria dos dados experimentais da literatura e aos resultados proporcionados pelos métodos de previsão. Entretanto, para nanofluidos com composições distintas de nanopartículas de alumina em água, comportamentos similares ao do presente estudo também são observados na literatura. No caso do ângulo de contato, verificou-se seu decréscimo com o incremento da concentração de nanopartículas. Tal resultado coincide com a bibliografia consultada, segundo a qual a molhabilidade do nanofluido se eleva com o incremento da concentração de nanopartículas. / The present study concerns the characterization of thermodynamic and transport properties of nanofluids based on alumina nanoparticles in deionized water. Stable suspensions were obtained using an ultrasonic homogenizer (Sonicator). The following properties were measured: i) thermal conductivity using the linear probe method, ii) dynamic viscosity through a cone-plate rheometer iii) contact angle, based on photographic of nanofluid drops on a flat surface and image processing through a program based on LabVIEW. The methods and experimental procedures were validated by performing measurements properties of pure fluids with well known characteristics. Besides the experimental study, it was performed a comprehensive literature review on thermal conductivity and dynamic viscosity of nanofluids. Experimental results were compared against the data from the literature and the respective predictive methods developed for suspensions of nanofluids and micro solid particles in liquid. Generally speaking, the nanofluid thermal conductivity and dynamic viscosity measured in the present study were higher than the empirical values from the literature and the values given by predictive methods. However, it should be highlighted that although for different compositions of nanofluids behaviors similar to the one observed in this study are also reported in the literature. In case of contact angle, it was found that its value decreases with increasing the nanoparticle volumetric concentration. Such results is coincident with literature reports according to which the nanofluid wettability, given in terms of the contact angle, increases with increasing the nanoparticle concentration.