Article
Engineering, Mechanical
Maximilian Uhler, Mareike Schonhoff, Timo A. Nees, Tanja Wonerow, Jens Nuppnau, Frank Mantwill, Jan Philippe Kretzer, Stefan Schroeder
Summary: Due to different rheological behavior, wear tests cannot replicate the in vivo situation completely. This study found that two different test fluids have different rheological properties before and during the test, and undergo considerable changes over test duration, which can impact the interpretation of wear test results.
Article
Physics, Multidisciplinary
Debarghya Banerjee, Vincenzo Vitelli, Frank Juelicher, Piotr Surowka
Summary: The mechanical response of active media, including biological gels and living tissues, is influenced by the interplay between viscosity and elasticity. By generalizing canonical models to active viscoelastic media that break symmetries, the resulting theories exhibit viscous and elastic tensors that are odd under index exchange. The analysis focuses on how these parity-violating viscoelastic coefficients impact relaxation mechanisms and wave-propagation properties of odd materials.
PHYSICAL REVIEW LETTERS
(2021)
Article
Materials Science, Multidisciplinary
Helene Meheust, Jean-Francois Le Meins, Etienne Grau, Henri Cramail
Summary: This study aimed to design bio-based polyesters as viscosity modifiers for lubricant properties and investigated their thermal properties. Results showed that bio-based polyricinoleate and its saturated homologous polyhydroxystearate have potential applications as viscosity modifiers in organic and mineral oils.
ACS APPLIED POLYMER MATERIALS
(2021)
Article
Materials Science, Multidisciplinary
Mohammad Hemmat Esfe, S. Ali Eftekhari, S. Mohammad Sajadi, Mohammad Hashemian, Soheil Salahshour, Seyed Majid Motallebi
Summary: In this study, an artificial neural network was used to predict the dynamic viscosity of MWCNT-ZnO (25:75)/SAE 10W40 oil nano-lubricant. The temperature, shear rate, and solid volume fraction were found to have significant effects on the dynamic viscosity, with shear rate being the most influential parameter.
MATERIALS TODAY COMMUNICATIONS
(2024)
Article
Engineering, Mechanical
Peng Yue, Yujuan Zhang, Shengmao Zhang, Jiajia Jia, Kun Han, Ningning Song
Summary: The non-bonding interactions of four interfaces with typical polar interfacial characteristics have been simulated using molecular dynamics methods. The effects of Coulomb and Van der Waals terms in the optimized potentials for liquid simulations all-atom (OPLS_AA) force field on the arrangement behavior of lubricant molecules are investigated. A mathematical model is proposed to quantitatively characterize the influence on the tilt degree of lubricant molecules near nano-silica surfaces. The tilt degree at the interface is determined by the molecular chain tilt factor γ, which is calculated by considering the polar characteristics of the solid surface, the characteristics of the polar units within the liquid molecules, and the linking modes between them.
TRIBOLOGY INTERNATIONAL
(2023)
Article
Agricultural Engineering
J. F. Rubio-Valle, M. C. Sanchez, C. Valencia, J. E. Martin-Alfonso, J. M. Franco
Summary: In this study, electrospun lignin/cellulose acetate fiber-bead nanostructures were developed as structuring agents for vegetable oils to be used as eco-friendly lubricating oleogels. The morphology of the electrospun nanostructures was found to be strongly dependent on the rheological properties of the biopolymer solution. The rheological properties of these gel-like dispersions can be tailored through concentration and ratio, and the resulting oleogels have comparable properties to conventional lubricants.
INDUSTRIAL CROPS AND PRODUCTS
(2022)
Article
Geochemistry & Geophysics
A. Soldati, B. F. Houghton, D. B. Dingwell
Summary: During the 2018 Kilauea eruption, magma composition varied greatly from basalt to andesite, leading to different eruptive styles from fountaining to explosions. By collecting 18 representative samples immediately after the eruption and conducting high-temperature laboratory experiments, the study quantified the evolution of melt viscosity, showing a significant variability linked to eruption dynamics. A new standard for studying multi-episode effusive eruptions from a viscosity standpoint was proposed, aiming to make viscosity measurements during ongoing eruptions a routine part of volcano monitoring in the future.
Article
Engineering, Chemical
Christopher J. Dyson, Martin Priest, Peter M. Lee
Summary: The presence of lubricant droplets in the gas flow of an internal combustion engine has significant implications for performance, including lubricant supply, oil consumption, and lubricant degradation. The viscosity of the lubricant and the presence of viscosity modifiers have been found to play a crucial role in the formation of droplets.
Article
Biochemistry & Molecular Biology
M. Trejo-Caceres, M. Carmen Sanchez, J. E. Martin-Alfonso
Summary: The aim of this study was to investigate the impact of the acetylation process on kraft lignin for the development of bio-based semisolid lubricants. Lignin was acetylated with acetic anhydride and pyridine as a catalyst by modifying different reaction variables. The acetylated lignin was analyzed using various techniques to evaluate the changes induced by the acetylation process, and the rheological and tribological properties of dispersions were found to depend on the development of different microstructures.
INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
(2023)
Article
Materials Science, Paper & Wood
Claudia Roman, Miguel A. Delgado, Samuel D. Fernandez-Silva, Moises Garcia-Morales
Summary: The study demonstrates that the pre-treatment of nanofibers has a significant impact on the flow and shear behavior of lubricating oleogels. Oleogel based on chemically-prepared nanofibers is more sensitive to temperature and large shear deformations compared to oleogel based on mechanically-prepared nanofibers.
Article
Mathematics
Ilya I. Kudish, Sergei S. Volkov
Summary: This paper investigates the lubrication problem of a lightly loaded contact between two parallel cylinders lubricated by a non-Newtonian fluid with Giesekus rheology. The non-Newtonian rheology is advantageous in accurately describing the behavior of lubricants under high and low shear stresses. The problem is solved using a modified regular perturbation method and the obtained solution is numerically analyzed to study the dependence of various characteristics on input parameters.
Article
Chemistry, Physical
Mohammad Hemmat Esfe, Soheyl Alidoust, Saeed Esfandeh, Davood Toghraie, Erfan Mohammadnejad Ardeshiri
Summary: In this study, the rheological behavior of a hybrid nano-lubricant was analyzed to evaluate its performance as a modified engine oil. The experimental results showed that the nano-lubricant had improved viscosity compared to pure oil. A mathematical model was also developed using the response surface method to accurately predict the experimental data.
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
(2022)
Article
Materials Science, Ceramics
Allison S. S. Brandvold, Ghassan K. K. Al-Chaar, Waltraud M. M. Kriven
Summary: A series of experiments were carried out to investigate the rheological properties of potassium-based geopolymers, focusing on the influence of shear rate, recovery time, and shear ramping on thixotropy in the context of geopolymer setting reaction. The study found that a critical shear rate of 100 s(-1) is required for thixotropic disruption, full thixotropic restructuring occurs after approximately 90-100 min of undisturbed rest time, and achieving a complete thixotropic disturbance depends heavily on processing parameters. The crossover between storage and loss modulus during cyclical oscillatory measurements suggests the repeatability and reversibility of thixotropy in geopolymers, indicating the potential for adjustable viscosity. Overall, geopolymer pastes exhibit strong evidence of thixotropy, which is beneficial for additive manufacturing, and the rheological properties are significantly influenced by rest time and shear rate.
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
(2023)
Article
Engineering, Mechanical
Scott Bair
Summary: Recent progress in elastohydrodynamic lubrication (EHL) has been achieved through a shift in method from adjusting viscosity as a parameter to measuring it using viscometers. However, measuring shear-dependent viscosity in lubricating oils is challenging due to other phenomena affecting constitutive behavior. The lack of understanding of thermal feedback in viscometers has resulted in wasted effort in EHL friction research.
TRIBOLOGY INTERNATIONAL
(2022)
Article
Polymer Science
Petr Filip, Jana Zelenkova, Petra Peer
Summary: A new method for evaluating the initial polymer concentration required for the production of beadless nanofibres during electrospinning process is proposed in this study. This approach avoids the use of traditional concepts of overlap and entanglement concentrations, aiming to address the issue of inability to apply classical methods in specific material cases.
JOURNAL OF APPLIED POLYMER SCIENCE
(2021)
Article
Chemistry, Multidisciplinary
Mijndert van der Spek, Catherine Banet, Christian Bauer, Paolo Gabrielli, Ward Goldthorpe, Marco Mazzotti, Svend T. Munkejord, Nils A. Rokke, Nilay Shah, Nixon Sunny, Daniel Sutter, J. Martin Trusler, Matteo Gazzani
Summary: The role of hydrogen in the energy transition has evolved over the years, and the current focus is on its versatility in aiding the transition to CO2 neutrality. However, strong political support and robust infrastructure design are necessary for the realization of the hydrogen economy. Multiple barriers need to be addressed, including technology development, infrastructure co-creation, policy, market design, and business model development. This article provides a comprehensive understanding of the elements in the hydrogen economy, its current state, and the gaps that need to be filled.
ENERGY & ENVIRONMENTAL SCIENCE
(2022)
Article
Thermodynamics
Yolanda Sanchez-Vicente, J. P. Martin Trusler
Summary: This study reports saturated-phase densities for the CO2 + methylcyclohexane system and compares the results with predictions from two models. The densities were better predicted by the SAFT-gamma Mie model, while the PPR-78 model generally performed better for vapor-liquid equilibrium. This suggests that some parameters of the SAFT-gamma Mie model could be further optimized.
JOURNAL OF CHEMICAL AND ENGINEERING DATA
(2022)
Article
Energy & Fuels
Yolanda Sanchez-Vicente, J. P. Martin Trusler
Summary: Understanding the phase behavior of (CO2 + water + permanent gas) systems is important for carbon capture and storage (CCS) processes. The experimental and calculated results showed that different models had different prediction capabilities for different systems.
Article
Energy & Fuels
Humera Ansari, Shuwei Gong, J. P. Martin Trusler, Geoffrey Maitland, Ronny Pini
Summary: This study presents a hybrid pore-scale model for gas adsorption in shale, using surrogate surfaces to simulate the behavior. The reliability of the model is verified through comparisons with experimental data. The proposed model can reduce the experimental burden and has general applicability.
Article
Thermodynamics
Ziqing Pan, J. P. Martin Trusler
Summary: Interfacial tension (IFT) is an important property in enhanced oil recovery (EOR) and carbon geological storage (CGS), supporting the interpretation of multiphase flow and wetting behavior and facilitating reservoir simulation. This study investigates the effect of contrast agents on IFT using pendant-drop experiments and modeling, providing quantitative data on IFT between different phases and proposing a workflow for estimating IFT between gas, brine, and doped hydrocarbon systems.
FLUID PHASE EQUILIBRIA
(2022)
Article
Energy & Fuels
Kaiqiang Zhang, Apostolos Georgiadis, J. P. Martin Trusler
Summary: Interfacial tensions (IFTs) between crude oil and water or brine systems are critically important in many processes. This study provides a large database of crude oil-water/brine IFTs at different temperatures and pressures. The effects of temperature, pressure, and fluid composition on IFTs were evaluated and the dynamic evolution of IFTs was categorized and described.
Article
Thermodynamics
Ziqing Pan, J. P. Martin Trusler
Summary: Experimental interfacial tensions (IFTs) of CO2 and decane-iododecane mixtures were measured over a wide range of temperatures and pressures. The volume of the hydrocarbon drop initially increased while the IFT decreased before reaching equilibrium values. These observations are significant for understanding the mechanisms of CO2 flooding.
FLUID PHASE EQUILIBRIA
(2023)
Article
Thermodynamics
Ziqing Pan, J. P. Martin Trusler
Summary: The interfacial tensions between hydrocarbon-, water-, and CO2-rich phases were measured and modeled in this study. It was found that the dynamic IFT decreased over time until equilibrium was reached, and the equilibrium IFTs decreased with increasing pressure. The presence of CO2 reduced the system IFT, and a linear relationship between the equilibrium IFT and the CO2 concentration in the water-rich phase was observed. The density gradient theory coupled with the volume translated CPA equation of state accurately predicted the IFTs in the three-phase region.
FLUID PHASE EQUILIBRIA
(2023)
Review
Energy & Fuels
Carsten Wedler, J. P. Martin Trusler
Summary: Biodiesel fuels are comprised of a mixture of different fatty acid esters, which have significant effects on combustion and storage. This study reviews the available experimental data on density and viscosity of fatty acid methyl, ethyl, and butyl esters and identifies gaps in the literature. The research includes 16 different esters from three ester families and provides an overview of generalized models for describing density and viscosity at elevated pressures.
Article
Thermodynamics
Defne Demirdesen, Carsten Wedler, Robert E. Low, J. P. Martin Trusler
Summary: The speed of sound in 1,1-difluoroethene (refrigerant R1132a) was measured using a cylindrical acoustic resonator. The measurements were carried out at temperatures from 193 K to 383 K and pressures up to 85% of the vapour pressure or 3 MPa. The results were compared with a preliminary equation of state for 1,1-difluoroethene, showing deviations within +/- 0.3%.
INTERNATIONAL JOURNAL OF THERMOPHYSICS
(2023)
Article
Thermodynamics
Carsten Wedler, J. P. Martin Trusler
Summary: The speed of sound in helium was measured in a temperature range from 273 to 373 K and pressures from 15 to 100 MPa with an expanded uncertainty from 0.02% to 0.04% (k = 2). A dual-path pulse-echo system was used for the measurements. The results were compared with a reference equation of state and also with predictions based on the virial equation of state, showing agreement within experimental uncertainty.
JOURNAL OF CHEMICAL AND ENGINEERING DATA
(2023)
Article
Thermodynamics
Sijia Wang, Tong Zhou, Ziqing Pan, J. P. Martin Trusler
Summary: In this study, the diffusion coefficients of N(2)O and H-2 in water were determined using the Taylor dispersion technique under various temperatures and pressures. The results showed that temperature is the most influential factor in determining the diffusion coefficients.
JOURNAL OF CHEMICAL AND ENGINEERING DATA
(2023)
Article
Engineering, Chemical
Xiaoxian Yang, Christian Hanzelmann, Steffen Feja, J. P. Martin Trusler, Markus Richter
Summary: This study proposes a novel modeling approach for lubricant oils by treating them as quasi-pure fluids and using a minimal set of experimental data for parameter fitting. The results show that this approach provides accurate predictions, with uncertainties of less than 7% for pure or quasi-pure component properties in the liquid phase, and within 8% for all other properties of binary mixtures except for viscosity.
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
(2023)
Article
Thermodynamics
Subash Dhakal, Saif Z. S. Al Ghafri, Darren Rowland, Eric F. F. May, J. P. Martin Trusler, Paul L. L. Stanwix
Summary: Knowledge of thermodynamic properties of aqueous solutions of CO2 is crucial for various applications. However, there is a lack of reliable experimental data and the EOS predictions are not reliable, especially for low CO2 concentrations. In this study, we measured speeds of sound in three different aqueous solutions containing CO2. By analyzing the change in sound speeds as functions of composition, pressure, and temperature, we found that dissolution of CO2 in water increases its sound speeds at all conditions. Our sound speed data agree well with the limited available experimental data but deviate from the EOS-CG predictions at certain conditions.
INTERNATIONAL JOURNAL OF THERMOPHYSICS
(2023)
Article
Thermodynamics
Daniel Schick, Qiaoyun Chen, Lennart Hellfajer, Alexander Strangmann, Paul Figiel, J. P. Martin Trusler, Gabriele Sadowski, Christoph Held
Summary: In this study, the CO2 solubility in solvent mixtures containing NMP and water with additional electrolytes was predicted using the ePC-SAFT advanced model, and the predictions matched well with the experimental data. It was found that NMP increased the CO2 solubility while electrolytes caused a salting-out effect on the CO2 solubility. The influence of CO2, NMP, and electrolytes on the kinetics and equilibrium of the esterification reaction was also investigated, with CO2 and NMP showing a negative effect on the kinetics and NMP having a negative influence on the equilibrium.
JOURNAL OF CHEMICAL AND ENGINEERING DATA
(2023)