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The celebrated generalized Stokes law predicts that the velocity of a particle pulled through a liquid by an external force, Fex, is directly proportional to the force and inversely proportional to the friction ζ acted by the medium on the particle. We investigate the range of validity of the generalized Stokes law at molecular length scales by employing computer simulations to calculate friction by pulling a tagged particle with a constant force. We thus calculate friction for two model interaction potentials, Lennard-Jones and soft sphere, for several particle sizes, ranging from radius (a) smaller than the solvent particles to three times larger. We next obtain friction from diffusion (D) by using Einstein's relation between diffusion and friction ζ in an unperturbed liquid. We find a quantitative agreement between the two at a small-to-intermediate pulling force regime for all the sizes studied. The law does break down at a large pulling force beyond a threshold value. Importantly, the range of validity of Stokes' scheme to obtain friction increases substantially if we turn off the attractive part of the interaction potential. Additionally, we calculate the viscosity (η) of the unperturbed liquid and find a good agreement with the Stokes–Einstein relation ζ = Cηa for the viscosity dependence with a value of C close to 5 π, which is intermediate between the slip and stick boundary condition. [ABSTRACT FROM AUTHOR]

We report measurements of the shear viscosity η in water up to 150 MPa and down to 229.5 K. This corresponds to more than 30 K supercooling below the melting line. The temperature dependence is non-Arrhenius at all pressures, but its functional form at 0.1 MPa is qualitatively different from that at all pressures above 20 MPa. The pressure dependence is non-monotonic, with a pressure-induced decrease of viscosity by more than 50% at low temperature. Combining our data with literature data on the self-diffusion coefficient Ds of water, we check the Stokes-Einstein relation which, based on hydrodynamics, predicts constancy of Dsη/T, where T is the temperature. The observed temperature and pressure dependence of Dsη/T is analogous to that obtained in simulations of a realistic water model. This analogy suggests that our data are compatible with the existence of a liquid-liquid critical point at positive pressure in water. [ABSTRACT FROM AUTHOR]

At the early stages of drug development, the amount of drug materials is rather limited. In this case, viscosity measurement is often postponed to the later stages, where grams of proteins can be produced. Therefore, it is necessary to develop a viscometer capable of measuring the viscosity with high accuracy while requiring low sample volume. This study presents a novel viscosity measurement technique based on measuring the resonance frequency and motional resistance of a micropillar-enhanced acoustic wave (μPAW) device. The μPAW was developed by fabricating micropillars on the quartz crystal microbalance substrate in order to achieve ultra-high sensitivity, thanks to a unique coupling between the micropillar and the resonator. The experimental measurements demonstrated a nonlinear relationship between the density and viscosity of the fluid and the response of μPAW. A calibration correlation was developed using the response of μPAW in aqueous glycerol and sucrose solutions. The measurements were then extended using high-concentration BSA solutions as the model of protein solution. The main advantage of the μPAW device in this work over other viscometers is the ability to simultaneously measure solution viscosity and protein adsorption on the surface. This is a huge step forward in the development of sensing systems for the pharmaceutical industry, where real-time sensing of target biological proteins and measuring the viscosity of a solution is required. [ABSTRACT FROM AUTHOR]

The present studies reported the experimental data on thermophysical properties such as density and viscosity of aqueous solutions of different amino acids namely l-isoleucine, l-proline, and l-glutamine in 1.5 mol/L KCl solution at different temperatures ranging from 298.15 to 323.15 K. Hence, the aim of this study is to investigate interactions between amino acids and KCl solution at dilute concentrations. For understanding amino acid and KCl solution interactions, we will investigate ion–ion and ion–solvent interactions. It has been observed that the density and viscosity rise with amino acid concentration and decrease with temperature. Using the Jones–Dole equation, the viscosity A and B coefficients have been determined. The viscosity B-coefficient values for all the three amino acids in aqueous electrolyte system are depicted as positive. The positive values of B-coefficient indicate a strong alignment of the solvent molecules with solute molecules. The amino acid l-glutamine acts as a structure breaker solute. This structure breaking effect of l-glutamine on solvent may be attributed to the domination of hydrophilic nature of amide group. l-isoleucine and l-proline act as structure maker in electrolyte system. [ABSTRACT FROM AUTHOR]

The viscosities of Ce‐free and Ce‐bearing (∼1.3 mol%, ∼6.5 wt.% Ce2O3) soda lime silicate (window glass) melts were measured with respect to oxidation state. Experiments were performed isothermally using a concentric‐cylinder viscometer on melts equilibrated with successively reducing CO–CO2 gas mixtures within a gas tight vertical tube furnace at 1 atm. Viscosity measurement and sampling were performed at the end of each melt reduction step. Further, viscosities in the glass transition temperature range were estimated using the shift factor method applied to glass transition temperature values determined using differential scanning calorimetry (DSC) measurements on quenched glasses. The Ce speciation at each stepwise melt reduction was probed using Ce L3‐edge X‐ray absorption near‐edge structure (XANES) spectroscopy, while structural information upon Ce addition and reduction was provided by Raman spectroscopy. The viscosities of these materials remain constant at this level of Ce addition and do not vary significantly with redox state at high temperature. Conversely, viscosity values in the glass transition temperature range increase upon both Ce addition and reduction. Our analysis, based on the glass composition analyses obtained via electron probe microanalyzer (EPMA), viscosity calculations, and observations of silicate structural changes, leads to the conclusion that the observed viscosity increase around the glass transition temperature is explained by the high ionic field strength of Ce ions as well as the polymerization behavior of the silicate matrix occurring during reduction of Ce. Because of its low concentration, resulting from its low solubility, Ce redox changes exert only minimal effects on the viscosity of this melt. [ABSTRACT FROM AUTHOR]

Borosilicate glasses possess excellent melting properties and high stability against chemical attack by aqueous solutions, enabling this glass family to be used in various fields. In this article, we design a novel glass network in order to achieve a chemically robust glass with a low melting temperature. Therefore, the substitution effect of Na2O by MgO, Al2O3, Li2O, and K2O on the chemical durability and melting properties of sodium aluminosilicate glass (i.e., 80SiO2‒5Al2O3‒15Na2O [mol%]) was examined using a standard hydrolytic resistance test and viscosity measurement. Interestingly, we found that the partial replacement of Na2O by Al2O3, Li2O, and K2O (i.e., 80SiO2‒5Al2O3‒15Na2O → 80SiO2‒6.5Al2O3‒9Li2O‒2.25Na2O‒2.25K2O) makes the glass network with chemical durability and melting properties comparable to those of the commercial borosilicate network, resulting in a low HCl consumption of 0.04 mL/g and working temperature of 1238°C (i.e., temperature at viscosity 104 dPa s). The structural characterizations indicate that the high chemical stability of this glass composition originates from the abundance of SiO4 tetrahedrons with three and four bridging oxygen in the glass network as well as the increase in cationic field strength of mixed alkali ions. These excellent melting properties and superior chemical durability of glass imply the possibility of using the mixed alkali metal oxides aluminosilicate glass together with the commercial borosilicate glass in the markets for numerous practical applications. [ABSTRACT FROM AUTHOR]

Viscosity measurement is crucial in biomedical research and clinical diagnosis. Currently, rapid and non-contact methods for measuring viscosity remain challenging. We propose a method based on optical coherence tomography for fast, remote assessment of the liquid viscosity. The viscosity of the liquid sample was quantified according to Poiseuille's law, the flow velocity was determined using optical coherence tomography, and the real-time pressure difference was measured by two manometers. Glycerol–water mixtures with various viscosities were tested to assess the accuracy of the optical coherence tomography (OCT) viscosity measurement. Then, blood samples with different levels of hemodilution and hematocrit were measured to validate the feasibility of the OCT method in the blood viscosity measurement. The results indicate that the proposed method can provide rapid, non-contact liquid viscosity measurement. It could significantly impact research on hemodynamics and diagnosis of blood disorders. [ABSTRACT FROM AUTHOR]

The usage of liquefied hydrogen (LH 2) is growing fast as the EU aims to be climate-neutral by 2050. Therefore, reliable and consistent measurements of LH 2 amounts (as determined by flow meters) will become increasingly important for custody transfers. Reliability and consistency of measurements is established from calibration. Due to the lack of facilities being able to calibrate flow meters directly with LH 2 as calibration fluid, the question arises whether the measurement error of the calibration performed on a different fluid and different process conditions are representative for the errors when measuring LH 2. An on-site calibration of two turbine meters measuring LH 2 flow was performed. A Coriolis mass flow meter calibrated on water was used as a reference in conjunction with a dedicated flow meter model, which was validated by a directly SI-traceable calibration on liquefied natural gas. LH 2 flow rates were within 1000 kg/h and 3000 kg/h, which are relevant to hydrogen transport by LH 2 trailers. The analysis of the measurement data reveal errors on totalized mass ranging from 2.0 % to 2.9 % with a total calibration uncertainty of 1.3 % (k = 2), where the main uncertainty source was identified as the on-site density estimate necessary to convert the volume flow measurements into mass flow measurements. The results indicate the need for reliable and accurate temperature measurements (the latter allowing for an accurate density estimate), so that volume based and mass based amount measurements can be compared with smaller uncertainties. • Reliable measurements of liquefied hydrogen amounts will be crucial for custody transfer. • Direct calibration of flow meters on liquefied hydrogen is currently not possible. • Novel results of liquefied hydrogen flow measurement of an on-site calibration are presented. • The analysis reveals errors between 2.0 % and 2.9 % with an uncertainty of 1.3 % (coverage factor = 2). • The main uncertainty source was identified as the on-site density estimate. [ABSTRACT FROM AUTHOR]

Objectives: The aim of this study was to prepare a sustained-delivery mucoadhesive-thermosensitive formulation containing poloxamer 338 (P338), poloxamer 188 (P188), and mucoadhesive agents, such as chitosan (CHT) and carboxymethylcellulose (CMC), to increase the ophthalmic bioavailability of timolol maleate (TM). Materials and Methods: Gels were prepared by mixing different amounts of P338, P188, and a mucoadhesive agent in cold isotonic water using a magnetic stirrer. The sol-gel gelation time of the gels was determined using the test tube inversion method. Viscosity measurements and analysis of the mechanical properties of the gel formulations were performed. In vitro release using dialysis membranes and ex vivo permeation studies using fresh-warmed cow eyes were performed. Results: The gelation times of formulations containing 20:2.5 (P338:P188) and 0.1% CMC and formulations containing 20:2.5 (P338:P188) and 0.1% CHT were 35 s and 26.67 s, respectively. An optimally selected CHT mucoadhesive-thermosensitive in situ gelling system can successfully control the release of moderately hydrophilic drugs, such as TM. In the viscosity study, both formulations showed Newtonian fluid, and the CHT gel’s viscosity was found to be higher. The CHT gel showed better mechanical properties than the CMC gel. The amount of TM penetrating the cow cornea after 24 hours was 73.38%, 71.80%, 67.25%, and 60.55% from the CHT gel, CMC gel, TM solution, and commercial preparation, respectively. Conclusion: The improved mucoadhesive-thermosensitive in situ gelling system successfully controlled the release of TM. The significantly lower drainage of TM into the circulation compared with eye drops is an advantage in treating glaucoma, and the use of mucoadhesive agents increases drug penetration. [ABSTRACT FROM AUTHOR]

Essential for decision-making, measurement is a cornerstone of various fields including energy management. While direct methods exist for some quantities like length, most physico-chemical properties require indirect assessment based on observable effects. Historically, pressure was measured by the water column height, and temperature by mercury expansion. Recent advancements in artificial intelligence (AI) offer a transformative approach by combining vast datasets with traditional measurements. This holds immense potential for applications facing extreme conditions and involving complex fluids where measurement is extremely challenging (over 1500 K and 5 MPa). In this study, an AI model is evaluated to replace online rheometers (293–1173 K, 0.15–3.5 MPa). A machine learning model utilizes a neural network with up to 8000 neurons, eight hidden layers, and over 448 million parameters. Trained, tested, and validated on three experimental databases with over 600 test conditions, the New Generation Predicted Viscosity Sensor (NGPV sensor) achieves exceptional accuracy (less than 4.8 × 10−7 Pa·s). This virtualized sensor proves highly relevant for hypersonic airbreathing applications involving fuel degradation and energy conversion. It maintains excellent predictability (accuracy below 6 × 10−6 Pa·s) even at flow rates 10 times higher than calibration, surpassing traditional rheometers limited by calibration needs and a lower viscosity measurement threshold (10−4 Pa·s). [ABSTRACT FROM AUTHOR]

This study employs a combined experimental and theoretical approach to investigate the thermophysical properties of eucalyptol (EC) blended with a series of 1-alkanols (ranging from 1-hexanol to 1-nonanol) across a temperature spectrum of 293.15–323.15 K. Density Functional Theory (DFT) calculations at the M05-2x/6-31g(d,p) level of theory are used to optimize the geometry of EC + 1-alkanols and provide insights into the hydrogen bonding interactions between the molecules. The DFT results reveal the significance of alkyl chain length in 1-alkanols on the hydrogen bonding with EC, which is supported by the analysis of geometrical, topological properties, vibrational frequency, NMR, and molecular orbital analysis. The theoretical findings are complemented by experimental measurements of density and viscosity, which show negative deviations from ideality in excess molar volume and viscosity. This study highlights the power of DFT methods in elucidating the molecular-level interactions governing the thermophysical properties of complex binary systems. Furthermore, the DFT results provide a molecular-level understanding of the observed thermophysical behavior, allowing for the development of more accurate predictive models. The integration of experimental and theoretical approaches in this study demonstrates a powerful framework for investigating the properties of complex mixtures. [ABSTRACT FROM AUTHOR]

Viscosity is a thermophysical property of paramount importance, being essential for many scientific and industrial applications. The most common instruments for its measurement are glass capillary viscometers. Therefore, the use of capillary viscometers is widespread both in industry and in research. The range of viscosities of interest range from lower than that of water to several orders of magnitude higher values, the measurement of which requires different capillary viscometers. Most of the practical applications concern routine instruments, mainly for quality control. One main issue for the utilization of capillary viscometers relates to the need for their calibration, assuring its traceability to the water primary viscosity standard, to certify its worldwide validity. The present paper focuses on capillary instruments dedicated to perform viscosity measurements on Newtonian organic liquids at atmospheric pressure, as it is assumed that is the most widespread type of application for these viscometers. Capillary viscometry has a completely well-defined working equation, namely, the Hagen–Poiseuille equation. However, the practical performance of the measuring instruments deviates from that working equation. Most of those deviations are currently considered by many users. However, some of those deviations have not reached that status yet, like those concerning the effects due to the surface tension of the sample on the measurements. All these aspects are summarized and analyzed in the present article, together with a brief general description of the most common types of capillary viscometers, namely, the Ostwald and the constant-level or Ubbelohde instruments. [ABSTRACT FROM AUTHOR]

Understanding of thermophysical and transport properties of H2-NG blends are needed for the gradual introduction of hydrogen into the national gas grid. A capillary tube viscometer was used to measure the viscosity of hydrogen + methane blends (with hydrogen mole fraction = 0, 0.1000, 0.1997, 0.5019, and 1) at temperatures from 213 to 324 K and pressures up to 31 MPa. A total 147 experimental viscosity measurements were made for the three H2 + CH4 blends and compared against the predictions of five different viscosity models: a one-reference corresponding states (Pedersen) model, a two-reference corresponding states (CS2) model, an extended corresponding states (ECS) model, a corresponding states model derived from molecular dynamic simulations of Lennard Jones (LJ) fluids, and a residual entropy scaling (SRES) method. All the model predictions showed a relatively low deviation compared to the measured viscosities. The density required for viscosity model predictions were computed using Multi-Fluid Helmholtz Energy Approximation (MFHEA) equations of state (EoS). To check the experimental procedure and applicability of the viscometer equipment, viscosity validation measurements were carried out for propane, hydrogen, and methane. The measured viscosities of the pure components were in good agreement with the respective viscosity models with AARD of 0.24%, 0.25%, and 0.58% for propane, hydrogen, and methane, respectively. [ABSTRACT FROM AUTHOR]

We fabricated a gas dynamic virtual nozzle using a three-dimensional (3D) printer to produce a jet of viscoelastic fluid. Aqueous alginate with concentrations of 0.5%, 1%, and 1.5% served as the dispersed phase, air as the continuous phase, and a high-speed camera for flow visualization. Viscosity and relaxation time measurements indicated that the zero shear rate viscosities of aqueous alginates were 0.055 , 0.2, and 1.2 Pa s , with relaxation times of 0.15 , 0.79 , and 2.3 ms for concentrations of 0.5%, 1%, and 1.5%, respectively. The emphasis was on understanding the effects of shear-thinning, alginate concentrations, and elasticity on regimes, jet size, and intact jet length. Analytical solutions and scaling laws were derived and compared with experimental data and literature. For Newtonian and laminar flow, we demonstrated the linear dependency of jet diameter on the Reynolds number through the derived scaling law. The measured jet diameter for non-Newtonian fluids significantly deviates from water due to their viscoelastic nature. At 0.5 psi, the dimensionless diameter differences were nearly 42% and 37% for flow rates of 5 and 15 μ l/s, respectively. The peak intact jet length, observed at 0.5 psi, was nearly 60% higher for 0.5% aqueous alginate than for water. Using the Buckingham π theorem, we identified nondimensional groups and developed correlations to predict jet diameter across a wide range of viscosities, relaxation times, and operating conditions. [ABSTRACT FROM AUTHOR]

This document is a correction notice for an article titled "Rheological characteristics of bauxite slurry with varying concentration, particle size distribution, and modal distribution for pipeline transportation" published in the journal Particulate Science & Technology. The correction addresses an error in the unit of measurement for dynamic viscosity in Figures 4(b), 5(b), 6(b), 7(b), 8(b), and 9(b), which was incorrectly listed as "(mPa)". The correct unit of measurement is "(mPa.s)". The corrected figures have been republished online. [Extracted from the article]

The rise of groundwater level and the acceleration of flow velocity in the discharge section of a geothermal system is difficult to explain by gravity-driven groundwater system theory alone. The temperature of groundwater increases after being heated in the geothermal systems, resulting in a decrease in groundwater density, an increase in salinity, and a decrease in viscosity. These changes create additional pressure heads, which are collectively recorded as geothermal driving forces. Based on the hydrochemistry and isotopes of hot springs in the Heyuan fault zone, South China, the geothermal driving force was evaluated as a case study. The geothermal driving force, which is mainly caused by the increase of groundwater temperature, increases with the increase of groundwater temperature and decreases with the increase of groundwater salinity. At the deepest position of groundwater circulation in the Heyuan geothermal field, the groundwater temperature reaches a maximum of 113.42°C, and the geothermal driving force generated here also reaches a maximum of +255.88 m. The geothermal driving force gradually decreases from deep to shallow in the Heyuan fault zone, but it makes the average vertical flow velocity of groundwater increase from 3.3×10−3 m/d in the recharge section to 16.8×10−3 m/d in the discharge section. Therefore, the geothermal driving force exists in the discharge section of the geothermal system, and its additional effect accelerates the flow of geothermal water in the discharge section. [ABSTRACT FROM AUTHOR]

Extensive experimental research and hydrodynamic models have been proposed to guide the design of superior packings. However, most research has concentrated on the effective void (ε − H) of packing while ignoring the ineffective void (ε − H − HL), which causes discrepancies in hydrodynamic performance compared to actual observations. This study evaluated the hydrodynamic performance under diverse conditions considering the liquid holdup (H), pressure drop (ΔP), and gas flooding velocity (uf). A novel approach to hydrodynamic model construction is introduced by incorporating an ineffective void. The results indicate that at a constant hold‐up area, liquid flow (L) and viscosity (μ) significantly influence liquid hold up, moderated by the gas velocity in the flooding area. The pressure drop rises as the viscosity, gas flow rate, and liquid flow rate increase. Notably, a considerable pressure drop initiates flooding at the bottom of the absorber. Elevated liquid flow rates and viscosities correlate with higher ineffective void values (HL) in the packing column. At low gas flow rates, the gas flow rate marginally affects HL values. However, after the flooding point was achieved, the values of HL rapidly increased as the gas flow rate increased. Moreover, a linear relationship emerges between the liquid holdup and HL, as evidenced by the consistent variation in the liquid holdup and the F‐factor. Utilizing the ineffective void yields a more accurate fit for the experimental data, reducing the average absolute relative deviation to 10.2%, 7.4%, and 10.8%, respectively. [ABSTRACT FROM AUTHOR]

AbstractThis article aims to assess the performance characteristics of lab-grown graphene nanoparticles via electrolytic exfoliation as nano additives in engine oil. Physical characterization confirmed the morphology and purity of the prepared graphene nanoparticles. Nanolubricants were prepared at 0.1%, 0.2%, and 0.3% volume fraction of the nanoparticles with the addition of oleic acid as surfactant. Measurements of density and viscosity for the nanolubricants were recorded at varying concentrations and temperatures. The performance parameters of a 4-stroke single-cylinder compression ignition (CI) engine were computed using the formulated nanolubricants. The emission of toxic gases into the environment post-engine performance evaluation was also analyzed for different formulations of nanolubricant samples. Results showed that the relative viscosity variation with concentration for the experimental data was in well agreement with other available predictive models. The nanolubricant with 0.1% concentration yielded a reduction of 13.96 ± 0.39% in total fuel consumption (TFC), a reduction of 5.55 ± 0.17% in brake-specific fuel consumption (BSFC) and an augmentation of 3.96 ± 0.13% in brake thermal efficiency (BTE) in comparison to plain engine oil and other prepared formulations. Also, a marginal reduction in emission of exhaust toxic gases i.e., (2.13 ± 0.1%) ppm in NOx and a significant maximum reduction of 7.46 ± 0.2% in smoke opacity has been obtained with 0.1% nanolubricant sample as compared to other test samples. The results from the present study may be useful for developing sustainable nanolubricants for environmental viability and energy savings. [ABSTRACT FROM AUTHOR]

Physical properties of blood plasma, such as viscosity, serve as crucial indicators of disease. The inherent capillary effect of paper microchannels, coupled with minimal sample requirement, stimulated the advancement of paper-based viscometers. This study presents a precise, non-contact optoelectronic system using a microfluidic platform for the measurement of blood plasma viscosity. Microchannels were defined onto the filter paper using an available and inexpensive wax crayon, without the need for conventional wax printing equipment. The time required for the 5 μL sample to pass a specific distance was measured using two pairs of infrared sensors. Subsequently, this data was sent to the microcontroller, which automatically calculated the viscosity. Throughout the measurements, sample temperature was maintained at a constant 37 °C through an integrated heater with automated control. The microfluidic platform successfully processed real samples, yielding viscosity measurements in under three minutes. Evaluation with fetal bovine serum, spiked with varying protein concentrations in both native and denatured states, demonstrated a precision exceeding 96% compared to conventional Ostwald viscometer readings. For human subjects exhibiting pathologies affecting serum and plasma viscosity compared to physiological norms, strong correlations were observed between resultant values and clinical diagnoses. The proposed device aims to replace expensive and complex optical equipment, offering a safer alternative for measuring plasma viscosity. Unlike similar devices, it eliminates the risk of component deformation due to chemical contact or unsafe irradiation. [ABSTRACT FROM AUTHOR]

Dispersion of Basil seed gum has high viscosity and exhibits shear-thinning behavior. This study aimed to analyze the influence of microwave treatment (MT) at various time intervals (0, 1, 2, and 3 min) on the viscosity and rheological behavior of Basil seed gum dispersion (0.5%, w/v). The finding of this study revealed that the apparent viscosity of Basil seed gum dispersion (non-treated dispersion) reduced from 0.330 Pa.s to 0.068 Pa.s as the shear rate (SR) increased from 12.2 s−1 to 171.2 s−1. Additionally, the apparent viscosity of the Basil seed gum dispersion reduced from 0.173 Pa.s to 0.100 Pa.s as the MT time increased from 0 to 3 min (SR = 61 s−1). The rheological properties of gum dispersion were successfully modeled using Power law (PL), Bingham, Herschel–Bulkley (HB), and Casson models, and the PL model was the best one for describing the behavior of Basil seed gum dispersion. The PL model showed an excellent performance with the maximum r-value (mean r-value = 0.942) and the minimum sum of squared error (SSE) values (mean SSE value = 5.265) and root mean square error (RMSE) values (mean RMSE value = 0.624) for all gum dispersion. MT had a considerable effect on the changes in the consistency coefficient (k-value) and flow behavior index (n-value) of Basil seed gum dispersion (p < 0.05). The k-value of Basil seed gum dispersion decreased significantly from 3.149 Pa.sn to 1.153 Pa.sn (p < 0.05) with increasing MT time from 0 to 3 min. The n-value of Basil seed gum dispersion increased significantly from 0.25 to 0.42 (p < 0.05) as the MT time increased. The Bingham plastic viscosity of Basil seed gum dispersion increased significantly from 0.029 Pa.s to 0.039 Pa.s (p < 0.05) while the duration of MT increased. The Casson yield stress of Basil seed gum dispersion notably reduced from 5.010 Pa to 2.165 Pa (p < 0.05) with increasing MT time from 0 to 3 min. [ABSTRACT FROM AUTHOR]

The accurate estimation of gas viscosity remains a pivotal concern for petroleum engineers, exerting substantial influence on the modeling efficacy of natural gas operations. Due to their time-consuming and costly nature, experimental measurements of gas viscosity are challenging. Data-based machine learning (ML) techniques afford a resourceful and less exhausting substitution, aiding research and industry at gas modeling that is incredible to reach in the laboratory. Statistical approaches were used to analyze the experimental data before applying machine learning. Seven machine learning techniques specifically Linear Regression, random forest (RF), decision trees, gradient boosting, K-nearest neighbors, Nu support vector regression (NuSVR), and artificial neural network (ANN) were applied for the prediction of methane (CH4), nitrogen (N2), and natural gas mixture viscosities. More than 4304 datasets from real experimental data utilizing pressure, temperature, and gas density were employed for developing ML models. Furthermore, three novel correlations have developed for the viscosity of CH4, N2, and composite gas using ANN. Results revealed that models and anticipated correlations predicted methane, nitrogen, and natural gas mixture viscosities with high precision. Results designated that the ANN, RF, and gradient Boosting models have performed better with a coefficient of determination (R2) of 0.99 for testing data sets of methane, nitrogen, and natural gas mixture viscosities. However, linear regression and NuSVR have performed poorly with a coefficient of determination (R2) of 0.07 and − 0.01 respectively for testing data sets of nitrogen viscosity. Such machine learning models offer the industry and research a cost-effective and fast tool for accurately approximating the viscosities of methane, nitrogen, and gas mixture under normal and harsh conditions. [ABSTRACT FROM AUTHOR]

The paper describes the theory and practice associated with the torsional quartz-crystal viscometer for the measurement of the viscosity of Newtonian Fluids. It is an instrument that has been less often used than its quality merits, but it has the distinct advantages, shared with the vibrating-wire device, that it involves no bulk motion of fluid or a solid and that all measurements can be electrical. The temperature range that can be covered by the instrument is from 2 to 650 K and pressures have reached as much as 100 MPa. The review summarizes the most recent theory of the instrument and carefully sets out all of the many conditions that have to be satisfied by design so that a practical instrument conforms to the theory. Most of the conditions are readily satisfied. Two working equations are presented that could be used to evaluate the viscosity using the frequency at resonance of the crystal and the bandwidth of that resonance when the crystal is immersed in the fluid and in vacuo. It is explained that at present only one of these equations should be used for the evaluation. Several configurations of instruments that have been employed for measurements over a wide range of conditions are briefly described as well as the corrections necessary to operate the instrument with the highest accuracy. The overall relative uncertainty attainable with the instrument ranges from 0.005 to 0.02 at a 95% confidence level, depending upon the fluid density. [ABSTRACT FROM AUTHOR]

A thorough evaluation of the thermophysical properties of ethylcyclohexane (ECH) mixed with 2-alkanols (2-propanol to 2-hexanol) is presented across the temperature range of 293.15 to 323.15 K. The focus of this study is on the density and viscosity behavior of these systems. The experimental results demonstrate positive deviations from ideality in excess molar volume, while viscosity deviations are negative for all examined mixtures. This observation suggests the presence of weak intermolecular interactions between ECH and the 2-alkanol. These findings are consistent with the self-association behavior of 2-alkanol and the nonpolar nature of ECH, which disrupts the associated structures of the alcohols. Furthermore, the Friction theory (f-theory) was employed to model the viscosity of the binary mixtures. The f-theory exhibits excellent agreement with the experimental data, with a maximum deviation of only 2.24% observed in the ECH + 2-butanol system. This minimal discrepancy underscores the f-theory's efficacy in accurately correlating the viscosity measurements. [ABSTRACT FROM AUTHOR]

Inflammation of the synovium, known as synovitis, plays an important role in the pathogenesis of osteoarthritis (OA). Synovitis involves the release of a wide variety of pro‐inflammatory mediators in synovial fluid (SF) that damage the articular cartilage extracellular matrix and induce death and apoptosis in chondrocytes. The composition of synovial fluid is dramatically altered by inflammation in OA, with changes to both hyaluronic acid and lubricin, the primary lubricating molecules in SF. However, the relationship between key biochemical markers of joint inflammation and mechanical function of SF is not well understood. Here, we demonstrate the application of a novel analytical framework to measure the effective viscosity for SF lubrication of cartilage, which is distinct from conventional rheological viscosity. Notably, in a well‐established equine model of synovitis, this effective lubricating viscosity decreased by up to 10,000‐fold for synovitis SF compared to a ~4 fold change in conventional viscosity measurements. Further, the effective lubricating viscosity was strongly inversely correlated (r = −0.6 to −0.8) to multiple established biochemical markers of SF inflammation, including white blood cell count, prostaglandin E2 (PGE2), and chemokine ligand (CCLs) concentrations, while conventional measurements of viscosity were poorly correlated to these markers. These findings demonstrate the importance of experimental and analytical approaches to characterize functional lubricating properties of synovial fluid and their relationships to soluble biomarkers to better understand the progression of OA. [ABSTRACT FROM AUTHOR]

Lactobacillus rhamnosus is commonly found in several fermented dairy products. The safety of probiotic L. rhamnosus OP268117 strain 6481 was evaluated in this study using hemolytic and gelatinase activity tests. Hemolysins or gelatinases were not detected for this probiotic candidate and so it is considered safe for human use. Three different concentrations of gum arabic (GA) were added to the like-yogurt, which was previously inoculated with the probiotic starter stated earlier. The utilization of concentrations of 0.25%, 0.5%, and 1% GA, namely B, C, and D, respectively, resulted in a significant improvement (p < 0.001) in the viable count of L. rhamnosus compared to the control samples, namely A, with the highest number (18.93 × 109 CFU/ml) observed in treatment D containing 1% GA on the 14th day. Adding GA had a substantial impact on the moisture, protein, and fiber content of the samples, but it did not influence the percentage of fat. The treatment with 1% GA (D) exhibited the highest fiber content. The pH decreased gradually as GA concentration increased during storage. Furthermore, the yogurt with 1% and 0.75% GA (D and C) showed the highest viscosity measurements on the 14th day of storage. The addition of GA had a significant impact on all sensory attributes, except for flavor, which was only minimally affected. The grades for appearance and texture were improved as the GA content increased. Thus, it is recommended to incorporate L. rhamnosus in the production of yogurt, together with 1% GA as a prebiotic to enhance the nutritional composition, overall appeal, and survival rate of the probiotics employed in the fermentation process. [ABSTRACT FROM AUTHOR]

Carbon nanotubes are very desirable for use in the production of electrochemical appliances due to their attractive properties, which include strong tensile strength, high conductivity of electricity, and chemical, thermal, and mechanical durability. Considering these fascinating properties of carbon nanotubes, we set out to investigate the numerical analysis for the steady 3D magnetic effects of heat and mass transmission on the flow of a Casson (non-Newtonian) hybrid nanofluid consisting of SWCNT and MWCNT combined with water as the base fluid across a permeable stretched sheet. The heat transfer induced by a rotating inclined stretched sheet is analyzed in relation to significant factors such as the rotational parameter, heat generation/absorption, the inclination angle parameter, heat radiation, and homogeneous–heterogeneous reactions. Also, the efficiency of hybrid nanofluid is studied with different shape factors. The physical flow model is then described as a set of partial differential equations that are subsequently transferred into an appropriate system of coupled nonlinear ordinary differential equations using the requisite similarity variables. In order to compute the transformed non-dimensional BVP model, the Runge–Kutta fourth-order methodology is used in conjunction with the shooting procedure. The graphical result shows that raising the heat source parameter and the Biot number increase the temperature profile, which improves the thermal boundary layer. The key characteristics of important flow variables are shown in graphs and tables, and the present findings are compared to prior studies, which show significant agreement. Nusselt number and friction drag analysis are also examined for fluid flow behavior. The results might help increase the performance of thermal engineering engines and equipment in a variety of industrial and thermal systems. [ABSTRACT FROM AUTHOR]

This work investigates transient non-colloidal suspension flows in cone-and-plate, plate-plate, and cylindrical geometries to assess particle motion's impact on viscosity measurement. Mass and momentum conservation equations model the two-phase liquid–solid flow, with both phases treated as continuous in an Euler-Euler approach. Findings demonstrate rheometric flow induces particle motion, affecting suspension homogeneity and viscosity measurement over time. Both buoyancy and inertia effects drive particle motion, with buoyancy dominating at low shear rates and inertia at high shear rates. Particle volume fractions, shear rates, and liquid viscosity notably influence viscosity measurements. Measurements with concentric cylinders are the least affected by particle motion. Additionally, we propose a time limit and a critical Reynolds number in which particle motion does not affect the measurement of the suspension viscosity. [ABSTRACT FROM AUTHOR]

In this paper, we leverage the direct numerical simulation (DNS) data for closed-channel flow for a range of friction Reynolds number (Reτ∼180–5,000) to develop a new one-point friction velocity method (OPFVM) to calculate friction velocity U* in terms of free-surface velocity Um , flow depth h , and kinematic viscosity ν. In contrast to prevalent methods that require several cumbersome near boundary measurements to obtain friction velocity, the OPFVM relies on a single easy-to-measure free-surface velocity measurement. The formulation is used to obtain friction velocity for a closed-channel flow (CCF) DNS regime with Reτ=10,049 and on four open-channel flow (OCF) DNS regimes with Reτ∼180–2,000. The same formulation was then experimentally verified in our laboratory. To avoid being prescriptive, a sensitivity analysis was performed to determine the permissible variation in Um to restrict the error in estimated U* to 2%. The relationship between the depth-averaged velocity Ub and the maximum free-stream velocity Um is also explored using the DNS data sets and an approximate relationship between Ub and Um is proposed. With advances in remote-sensing technology that enables free-stream velocity measurements, this method extends the potential to measure even the friction velocity remotely. Practical Applications: Measuring friction velocity U* is difficult in both laboratory and field settings for engineers and scientists. The proposed new method overcomes this challenge to estimate the friction velocity U* by measuring the velocity Um close to the free surface, flow depth h, and temperature (for viscosity). Because near-surface measurement of velocity is not difficult, this method greatly simplifies the measurement of U* with better accuracy than other prevalent methods in practice. In addition, direct numerical simulation (DNS) data has been used to estimate the average velocity Ub using the measured free-stream velocity Um , which further enables measurement of discharge using a single-point measurement of velocity near the free surface in smooth channels. [ABSTRACT FROM AUTHOR]

Electrical conductivity and viscosity of electroslag being crucial parameters. Using a high-temperature physical property measuring instrument, the effects of different TiO2 concentration and temperatures on electroslag conductivity and viscosity were investigated. With an increase from 1733 K to 1823 K resulting in elevated electrical conductivity (1.04 to 1.89 S · cm−1) and reduced viscosity (0.14 to 0.09 Pa · s). This is because the higher the temperature is, the more the polymer in the slag is depolymerized. Similarly, as TiO2 content increased from 7% to 16%, the electrical conductivity increased (0.24 to 1.14 S · cm−1), and the viscosity decreased (0.33 to 0.11 Pa · s). TiO2 simplified the structure of the melt, and based on the infrared and Raman spectral analysis, it can be seen that Ti4+ replaced Al3+ in the [AlO4]5− structure to form the Ti2O64−structural unit, which depolymerized the structure of the slag system, leading to the reduction of Q4 units and thus greatly reducing the electrical conductivity. The relationship between electrical conductivity, viscosity, and structure was quantified, demonstrating a clear inverse correlation between electrical conductivity and viscosity. The relationships offer insights into predicting electrical conductivity and viscosity based on slag structure. [ABSTRACT FROM AUTHOR]

In the present work, we demonstrate that zero‐shear viscosity is a sensitive rheological function to detect phase inversion in immiscible binary polymer blends characterized by a viscosity ratio larger than one. The phase inversion of poly(propylene) (PP)/low‐density poly(ethylene) (LDPE) and poly(styrene) (PS)/LDPE, at various compositions, was assessed via our novel approach. For both blends, three distinctive regions could be determined through zero‐shear viscosity measurements; the LDPE matrix, the co‐continuous phase, and the PS or PP matrix. For PP/LDPE blends, the co‐continuous structure was between 50 and 75 wt.% PP, and for PS/LDPE blends the co‐continuous structure was between 45 and 75 wt.% PS, in agreement with scanning electron microscopy analysis, empirical model predictions, and literature data. Highlights: Phase inversion revealed via viscosity measurements.Limitations of linear viscoelastic models for immiscible blends assessed. [ABSTRACT FROM AUTHOR]

The primary objective of this study was to investigate the correlations between instrument measurements and sensory attributes of thickened liquids. For this purpose, a series of thickened liquids was prepared using different thickening agent contents from different sources, which were evaluated by sensory analysis for sensory attributes and by instrument measurements for specific physical properties. The texture attributes (hardness, ease of swallowing, and coating (oral cavity, residual feeling in the throat)) of 12 thickened liquid samples were investigated by sensory evaluation. The investigators were 10 panelists trained in evaluating sensory attributes. The line spread test (LST) and the short back extrusion (SBE) method were used for the instrumental analysis. The correlation coefficient between physical properties and each sensory evaluation value was also determined. The results showed that the apparent viscosity from viscosity measurements was highly correlated with each sensory attribute. As thickened liquid is a non-Newtonian fluid, the apparent viscosity was dependent on the shear rate. Hence, the instrumental texture perception of sol (thickened liquid) based on the oral cavity condition could be used to predict human texture perception based on the shear rate, which was obtained from the apparent viscosity similar to gel (strawberry jam). These results indicate that the SBE method is better than the LST for measuring the texture attributes of thickened liquids. [ABSTRACT FROM AUTHOR]

The greater the viscosity of the blood, the more difficult its flow becomes, leading to an increased incidence of diseases caused by blood circulation disorders. These diseases are commonly associated with the cardiovascular and cerebrovascular systems.High blood viscosity is a primary cause of circulatory system diseases. Studies have shown that accurately measuring blood viscosity and applying this data in clinical trials can help prevent circulatory system diseases.Viscosity data can vary depending on the measurement methods used, even when these methods are based on hydrodynamic principles. Despite using approved blood viscometers, the results often differ depending on the type of viscometer used, potentially causing confusion within the medical field. Informing the medical community about these differences and the level of error associated with each measurement method can help reduce this confusion.To our knowledge, the degree of difference in viscosity measurement results due to different measurement methods and the reasons for these differences have not yet been thoroughly explored. In this study, we selected three blood viscosity measurement methods registered with the Ministry of Food and Drug Safety of Korea to analyze the same canine blood. The viscosity measurements were carried out using each device and compared. The parallel plate and scanning capillary methods yielded similar viscosity values, while the cone plate method showed lower viscosity values.The viscosity of blood, as measured by the three viscometers, differed, indicating that more experimental data must be accumulated to evaluate the cause of these differences. In this paper, we identified several causes of inconsistency and suggested measures to avoid this confusion. However, confirming that the test results show systematic differences is expected to assist clinicians who diagnose and prescribe treatments based on blood viscosity results. The findings of this comparative study are anticipated to serve as a starting point for establishing guidelines or standards for blood viscosity measurement methods. [ABSTRACT FROM AUTHOR]

Measuring viscosity in volumes smaller than a microliter is a challenging endeavor. A new type of microscopic viscometers is presented to assess the viscosity of Newtonian liquids. Micron-sized flexible polymer cantilevers are created by two-photon polymerization direct laser writing. Because of the low stiffness and high elasticity of the polymer material the microcantilevers exhibit pronounced Brownian motion when submerged in a liquid medium. By imaging the cantilever's spherically shaped end, these fluctuations can be tracked with high accuracy. The hydrodynamic resistance of the microviscometer is determined by fitting the power spectral density of the measured fluctuations with a theoretical frequency dependence. Validation measurements in water-glycerol mixtures with known viscosities reveal excellent linearity of the hydrodynamic resistance to viscosity, allowing for a simple linear calibration. The stand-alone viscometer structures have a characteristic size of a few tens of microns and only require a very basic external instrumentation in the form of microscopic imaging at moderate framerates (~ 100 fps). Thus, our results point to a practical and simple to use ultra-low volume viscometer that can be integrated into lab-on-a-chip devices. [ABSTRACT FROM AUTHOR]

Highly reactive fission product cesium may volatilize at high temperatures. PbO–B 2 O 3 –ZnO glass with low melting temperature and excellent chemical durability can be used as a potential matrix for immobilizing Cs. In this work, five PbO–B 2 O 3 –ZnO glasses with different contents of Pb were synthesized via a melt-quenching process. These specimens were characterized with XRD, Raman, DTA and viscosity measurements. The results showed that the melting temperature decreases, viscosity decreases and structural polymerization increases with increasing lead content. Cs-doped 35PbO–60B 2 O 3 –5ZnO glasses were synthesized at low temperatures. XRD results revealed the amorphous nature of the glass solidified bodies. EDS and ICP-MS studies confirmed that Cs is retained in the glass. Clear vitrified waste products containing up to 13.6 wt% Cs were obtained. The chemical durability of the samples was evaluated via PCT-A and MCC-1 method. For the glass solidified body comprising a Cs/matrix ratio of 0.136, the leaching rate of Cs was 1.6 × 10−1 g m−2 d−1 from the PCT test, which indicates that it has a good chemical stability. 35PbO–60B 2 O 3 –5ZnO glass was expected to be a suitable matrix for Cs immobilization. [ABSTRACT FROM AUTHOR]

The viscosity of the polymer melt has an impact on both the processing and properties of the product. However, conventional viscosity measurement methods have limitations such as strict testing conditions, large sample sizes, and long response times. This paper proposes a simplified method that utilizes differential scanning calorimetry to determine the viscosity–temperature relationship of the polymer melt. The research subjects consist of four noncrystalline polymers and five crystalline polymers. A new thermodynamic fragility formula of crystalline polymer is obtained. Additionally, high‐temperature limiting viscosity shows a good linear relationship with fragility. Compared with the traditional viscosity measurement, this method is a simpler and more effective way to model the viscosity of polymer melt and has broad prospects in application. [ABSTRACT FROM AUTHOR]

We demonstrate the potential of unimorph beams equipped with macro fiber composites to integrate viscosity sensing and energy harvesting functionalities into a single device. The viscosity sensing component involves measuring the quality factor and resonance frequency peak associated with the second out-of-plane mode of vibration. We showcase the suitability of the present sensing device for liquids of wide range of kinematic viscosities from 1 to 1543.5 cSt. Following the quality factor-based sensing approach, the sensor reached a sensitivity of S = −0.0019/cSt. The amplitude-based sensing mechanism demonstrated a sensitivity of S = −3.3 mV/cSt. The viscosities of motor oil and glycerin, determined using the generated calibration curves, are found in close agreement with those obtained from a conventional rotational viscometer. The proposed sensing device holds great promise for online viscosity measurement, particularly for high-viscosity fluids, simple design, ease of operation, and partial self-sensing capability, thanks to energy harvesting. [ABSTRACT FROM AUTHOR]

The valorization of tannins from forest by‐products is a major opportunity for the sustainable development of the forestry industry. Herein we report the laccase‐mediated polymerization of tannins obtained from an aqueous pine bark extract. The reaction was conducted under an oxygen atmosphere at 50°C for 60 min and followed by UV–Vis, fluorescence intensity, phenol content, and viscosity measurements. An insoluble polymer was obtained after 45 min, which was attributed to coupling reactions triggered by phenoxyl radicals within the tannins mixture. The polymer showed a marked increase in thermal stability compared with the precursor pine bark extract, with a total mass loss of less than 12% at temperatures up to 500°C, suggesting potential practical applications in flame retardant materials. Additionally, the polymer showed an 85% DPPH activity and a 60% attenuation of singlet oxygen release upon light irradiation, which supports antioxidant and photoprotective properties for the prepared material. To the best of our knowledge, this is the first report to describe the formation of an insoluble polymer by direct enzymatic reaction of an aqueous tannin extract. In this case, soluble tannins are the sole reactants used to produce a promising versatile material for forest waste valorization. [ABSTRACT FROM AUTHOR]

A bis-(violurate)-based ruthenium(III) complex was synthesized in a pure form as nano-crystallites. Mass spectrum, elemental and thermal analysis, as well as molar conductance measurements, assigned the molecular formula [Ru(VA)2ClH2O]. FTIR, UV-vis, magnetic moment and ESR investigations suggested the structural formula as a distorted octahedron. Structural analysis by DFT calculations and processing of the PXRD data by the computer program Expo 2014 confirmed the proposed structure. Electronic and emission spectroscopy in addition to viscosity measurements displayed the greater binding capability of the [Ru(VA)2ClH2O] complex towards the studied biomolecules DNA and HSA as compared to uncomplexed violuric acid (VA). In vitro antiviral investigations against SARS-CoV-2 of violuric acid and the Ru(III) complex revealed greater activity in the case of the latter. Molecular docking studies reported that [Ru(VA)2ClH2O] binds more strongly to the spike protein of the tested virus cells (Vero-E6 cells), DNA, and HSA than the uncomplexed bis-(violurate) ligand system, consistent with the experimental results. [ABSTRACT FROM AUTHOR]

This article presents a novel material of acrylamide (AM) cross‐linked psyllium polysaccharides (PLP) derivative, PLP‐AM, which can be used as an effective polymeric flocculant for the removal of microplastics (MP) from water. PLP‐AM was produced by radical polymerization of PLP and AM using microwave irradiation instead of conventional radical initiators. The characterization of PLP‐AM was carried out by FT‐IR spectroscopy, elemental analysis, intrinsic viscosity measurement and thermogravimetric analysis (TG). Polystyrene (PS), polyethylene terephthalate (PET) and polyvinyl chloride (PVC) were utilized to examine the flocculation performance of PLP‐AM. The optimum flocculation conditions were obtained by the comprehensive exploration of flocculant concentration, solution pH and temperature. In a solution with a pH 6 at 30 °C, the maximum removal percentages of PS and PVC by 60 mg/L of PLP‐AM were 92.55 % and 94.31 %, respectively, while 93.85 % of the maximum removal of PET percentage could be obtained by 80 mg/L of PLP‐AM. The results of zeta potential measurement revealed that there was adsorption electric neutralization between MP and PLP‐AM besides the adsorption bridging mechanism. These results suggest that PLP‐AM may bring an inspiration for the development of polymer flocculant to remove MP from water. [ABSTRACT FROM AUTHOR]

Liquid density and viscosity of alternative refrigerants R513A were measured with a vibrating-wire viscosimeter in the temperature of 253 K to 363 K when pressure changes from 1 MPa to 12 MPa. The combined expended uncertainties with a confidence level of 0.95 (k = 2) of density and viscosity are 0.2 % and 2 %, respectively. In addition, a viscosity model of HFCs (fluorocarbons)/, HFOs (hydro-fluoroolefins) and their mixtures was provided by coupling the Perturbed-Chain Statistical Associating Fluid Theory (PC-SAFT) equation of state and a modified residual entropy scaling (RES) method. Obvious quasi-linear relation between the proposed entropy variable and the modified residual viscosity has been confirmed. The overall average absolute percentage deviations between the calculated results with the proposed RES model and the literature experimental data of pure and mixture refrigerants are 2.63 % and 2.05, respectively. [ABSTRACT FROM AUTHOR]

Background: Some of the factors that contribute to the quality of milk include fat content, pH, viscosity and other rheological aspects. This research extensively investigated the effects of ohmic heating (OH) on milk viscosity, along with other rheological attributes and pH. Methods: Milk samples with varied fat constituents were subjected to OH at a constant voltage of 140V until they reached a temperature of 90°C. The pH of raw milk and heated milk was determined using an auto-pH meter, whereas the viscosity of the same was measured using a Brookfield viscometer that includes a wide range of characteristics, such as viscosity, temperature, shear stress and torque at various spindle rotation speeds. The current investigation used principal component analysis (PCA) as a key statistical approach. Result: The pH values exhibited little fluctuations during OH across several milk kinds, indicating mild acidification throughout the process, but the observed alterations did not reach statistical significance (p>0.05), suggesting that OH does not significantly affect milk pH. Viscosity measurements showed that the application of OH resulted in a decrease in the average viscosity of milk, suggesting changes in its ability to withstand shear forces. The correlation study revealed robust positive associations between viscosity and fat content (PC2-26.77%), as well as between rotational speed, shear rate and torque (PC1-53.72%) and a negative correlation with temperature, offering valuable insights into the dynamic properties of milk when subjected to thermal heat treatment. [ABSTRACT FROM AUTHOR]

We present a new wide-range correlation for the viscosity of ethene based on critically evaluated experimental data. The viscosity correlation is valid from the triple point to 450 K and up to 195 MPa. The average absolute percentage deviation of the fit for the primary data (including the critical region) is 1%, with a bias of 0.2%, The estimated uncertainty of the correlation in the gas and supercritical phases at pressures up to 195 MPa is 2.5% (at the 95% confidence level). For the dilute gas (pressures up to 0.1 MPa) in the temperature range 296 K to 450 K, the uncertainty is 0.5%. For the liquid phase at pressures up to 5.5 MPa the estimated uncertainty is 5.3%. The correlation includes a term for the critical enhancement that is significant only in a very narrow region very close to the critical point. It is less than 1% outside of the region around the critical point from 279.80 K ≤ T ≤ 290.27 K to 140.79 kg⋅m−3 ≤ ρ ≤ 293.08 kg⋅m−3. [ABSTRACT FROM AUTHOR]

Viscosity is a fundamental physical property of lava that dictates style and rate of effusive transport. Studies of lava viscosity have predominantly focused on measuring re-melted rocks in the laboratory. While these measurements are well-constrained in temperature, shear rate, and oxygen fugacity, they cannot reproduce the complexities of the natural emplacement environment. Field viscosity measurements of active lava are the only way to fully capture lava's properties, but such measurements are scarce, largely due to a lack of easy-to-use, portable, and accurate measurement devices. Thus, there is a need for developing suitable field instruments to help bolster the understanding of lava. Here, we present a new penetrometer capable of measuring a material's viscosity under the harsh conditions of natural lava emplacement. This device uses a stainless-steel tube with a semi-spherical tip fixed to a load cell that records axial force when pushed into a material, while simultaneously measuring the penetration depth via a free-moving tube that is pushed backward along the penetration tube. The device is portable (1.5 m long, 5.5 kg in weight) and uses a single-board computer for data acquisition. The penetrometer has an operational range from 2.5 × 102 to 2.1 × 105 Pa s and was calibrated for viscosities ranging from 5.0 × 102 to 1.6 × 105 Pa s. It was deployed to the 2023 Litli-Hrútur eruption in Iceland. These field measurements successfully recorded the in situ viscosities of the lava in the range of 1.2 × 104–3.4 × 104 Pa s, showcasing it as an efficient method of measuring natural lava viscosity. [ABSTRACT FROM AUTHOR]

Most of the oil reserves have remained unrecovered during primary and secondary recovery scenarios which raise the need for novel and more useful recovery methods to produce the unrecovered oil and increase the recovery factor as an Enhanced oil recovery method. As the most common oil recovery method, the performance of the water injection can be further enhanced by adding polymers to water by the mobility control mechanism. Nanoparticle and nanohybrid flooding are one of those novel methods which can recover oil using wettability alteration and IFT reduction mechanisms. In this study, we synthesized polyacrylamide-based nanohybrids such as graphene oxide (GO)/PAM and carbon nanotube (CNT)/PAM combine the advantages of both nanoparticle and polymer flooding using a novel and simple method. The effect of different mechanisms involved such as wettability alteration, IFT reduction, and mobility control were studied separately in form of contact angle, IFT, and viscosity measurements and in combination with each other in the form of coreflooding tests were studied. The stability of the synthesized nanohybrids against temperature and salinity was investigated using TGA and bulk tests. The effectiveness of these novel nanohybrids was never investigated to this extent. Our investigation showed that GO/PAM nanohybrids had better performance in IFT reduction and mobility control and CNT/PAM in wettability alteration. During coreflooding tests, the GO/PAM showed the highest light and heavy oil recoveries with recovering 63.8% and 28.57%, respectively, in comparison to CNT/PAM with recovery factors of 60.95% and 25.71%. Both of the nanohybrids showed great performance in oil recovery due to wettability alteration and IFT reduction but the GO/PAM showed the best performance because of its higher viscosity which made the mobility control of the injected fluid much better. [ABSTRACT FROM AUTHOR]

To address the two critical issues of evaluating the necessity of implementing cooling techniques and achieving real-time temperature control of drilling fluids underground in the current drilling fluid cooling technology, we first established a temperature and pressure coupled downhole heat transfer model, which can be used in both water-based and oil-based drilling fluid. Then, fourteen factors, which could affect wellbore temperature, were analyzed. Based on the standard deviation of the downhole temperature corresponding to each influencing factor, the influence of each factor was quantified. The influencing factors that can be used to guide the drilling fluid's cooling technology were drilling fluid thermal conductivity, drilling fluid heat capacity, drilling fluid density, drill strings rotation speed, pump rate, viscosity, ROP, and injection temperature. The nondominated sorting genetic algorithm was used to optimize these six parameters, but the optimization process took 182 min. Combining these eight parameters' influence rules with the nondominated sorting genetic algorithm can reduce the optimization time to 108 s. Theoretically, the downhole temperature has been demonstrated to increase with the inlet temperature increasing linearly under quasi-steady states. Combining this law and PID, the downhole temperature can be controlled, which can reduce the energy for cooling the surface drilling fluid and can ensure the downhole temperature reaches the set value as soon as possible. [ABSTRACT FROM AUTHOR]

To elucidate an antitumor drug exhibiting enhanced activity relative to cisplatin, a novel dinuclear gold(III) complex was synthesized, incorporating 1,5-naphthyridine as a bridging ligand. Subsequently, the newly synthesized complex underwent comprehensive characterization using various techniques to validate its structural attributes. The stability of the complex in both water and PBS buffer was assessed through UV–Vis spectroscopy. DNA binding studies were conducted employing UV–Vis, fluorescence spectroscopy, and viscosity measurements. Competitive studies with ethidium bromide (EB) or 4′-hydroxyethidium (HOE) were performed utilizing fluorescence spectroscopy. The findings indicated that the dinuclear gold(III) complex interacts with calf thymus DNA (CT-DNA) through a groove binding mode. Moreover, the investigated complex exhibited significant binding constants for its interaction with human serum albumin (HSA) and bovine serum albumin (BSA) and interactions in the presence of site markers (eosin Y or ibuprofen). The dinuclear gold(III) complex demonstrated notable cytotoxicity against HCT116 and MDA-MB-231 cancer cell lines at 24 and 72 h post-treatment. Furthermore, the complex displayed selectivity by inducing significantly lower cytotoxic activity in healthy cells than in cancerous ones. In support of its antitumor activity, the complex exhibited proapoptotic effects, as evidenced by increased caspase 9 activity and low percentages of necrosis. Molecular docking simulations were employed to corroborate all experimentally obtained results. [ABSTRACT FROM AUTHOR]

This study investigated polyethylene glycol (PEG), as a polymer improver of the paraffinic oil viscosity index (VI). The characterization of PEG/paraffinic oil blends at different concentrations (0%, 1%, 2%, 3%, 5%, and 10%), was performed using Raman spectroscopy and optical microscopy. The rheological parameters as the viscosity index and activation energy were determined using the kinematic viscosity measurements. Results showed that the VI improvement reached an optimal value for the blend containing 3% PEG, with greater value for blends containing 2% PEG than 5 and 10% PEG. The presence of polymer particles was observed by optical microscopy, which confirmed the lack of PEG distribution in the blend containing 5%, and more, whereas mixtures with 3 and 2% PEG exhibited good particle distribution, evidenced by smaller polymer particle sizes. This finding was corroborated by Raman spectroscopy, which revealed the absence of polymer–oil intermolecular interactions in the PEG/paraffinic oil blends. The rheological tests showed that increasing the blend temperature from 40 to 80 ℃, improved the PEG chains dispersion in the paraffin oil, for the blends containing up to 3% PEG. The difference of the activation energy of the pure paraffinic oil and the PEG/paraffinic oil blends, (ΔEa) was calculated, and the correlation between the ΔEa and the viscosity index values was established. Therefore, adding PEG to paraffinic oil appeared to be promising for the viscosity index improvement and promote industrial applications of paraffinic oil. [ABSTRACT FROM AUTHOR]

The transdermal route is an important delivery system for the delivery of both systemic and local effects. The effectiveness of therapy is based on adherence of transdermal dosage form to the skin and physiochemical properties of the drug during therapy. Transdermal Film-Forming Gels when applied to the skin after adherence form a thin film and provide the delivery of drug to the body tissues. Novel 5-Fluorouracil loaded Film-Forming Gels was prepared by utilizing natural polymer (chitosan) with variable concentration of penetration enhancers i.e. oleic acid and tween 80 which further affects the drug release. Prepared Film-Forming Gels were subjected to pH determination, viscosity measurement, homogeneity determination and FTIR analysis. Drying test showed film-forming gel was dried within 15 min after application. Moreover, in-vitro release study confirmed the 83% release over 180 min and the ex-vivo release of FFG9 displayed 81.45% release. This novel system would be an effective dosage form for the delivery of drugs. [ABSTRACT FROM AUTHOR]