Power-law Model Research Articles

Search for a critical point of strongly-interacting matter in central 40\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$^{40}$$\\end{document}Ar + 45\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$^{45}$$\\end{document}Sc collisions at 13 A–75 A GeV/c beam momentum

The critical point of strongly interacting matter is searched for at the CERN SPS by the NA61/SHINE experiment in central 40\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$^{40}$$\\end{document}Ar + 45\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$^{45}$$\\end{document}Sc collisions at 13 A, 19 A, 30 A, 40 A, and 75 A GeV/c. The dependence of the second-order scaled factorial moments of proton multiplicity distributions on the number of subdivisions in transverse momentum space is measured. The intermittency analysis uses statistically independent data sets for every subdivision in transverse and cumulative-transverse momentum variables. The results obtained do not indicate the searched intermittent pattern. An upper limit on the fraction of correlated protons and the intermittency index is obtained based on a comparison with the Power-law Model.

Power-law growth models explain incidences and sizes of pancreatic cancer precursor lesions and confirm spatial genomic findings.

Pancreatic ductal adenocarcinoma is a rare but lethal cancer. Recent evidence suggests that pancreatic intraepithelial neoplasia (PanIN), a microscopic precursor lesion that gives rise to pancreatic cancer, is larger and more prevalent than previously believed. Better understanding of the growth-law dynamics of PanINs may improve our ability to understand how a miniscule fraction makes the transition to invasive cancer. Here, using three-dimensional tissue mapping, we analyzed >1000 PanINs and found that lesion size is distributed according to a power law. Our data suggest that in bulk, PanIN size can be predicted by general growth behavior without consideration for the heterogeneity of the pancreatic microenvironment or an individual's age, history, or lifestyle. Our models suggest that intraductal spread and fusing of lesions drive our observed size distribution. This analysis lays the groundwork for future mathematical modeling efforts integrating PanIN incidence, morphology, and molecular features to understand tumorigenesis and demonstrates the utility of combining experimental measurement with dynamic modeling in understanding tumorigenesis.

PFAS distribution in cascade derived foam at wastewater treatment plants: The role of non-linear drainage, collapse induced enrichment, and implications for removal

Per- and polyfluorinated alkyl substances (PFAS) enrichment in foam was investigated for the first time at a wastewater treatment plant cascade. A novel sampling device was utilized to allow spatial and temporal heterogeneity in PFAS concentrations and liquid content to be characterized. Concentrations of 8 PFAS compounds were normalized to liquid content and fit to a power law model revealing strong correlation (R2 = 0.91) between drainage induced enrichment and PFAS molar volume. Short chain PFAS such as perfluorobutanoate (PFBA) exhibited minor to no enrichment factors in foam (0.24–5.9) compared to effluent concentrations across the range of foam liquid contents (0.28–6.24 %), while long chain compounds such as perfluorooctane sulfonate (PFOS) became highly enriched with factors of 295–143,000. A conceptual model is proposed to explain higher than expected enrichment of more surface-active PFAS relative to liquid content, which combines continuous partitioning of PFAS to air bubbles during foam formation with additional partitioning during non-linear drainage and foam collapse, both controlled by their affinity for the air-water interface. Scoping calculations suggest the majority of PFOS and other long chain PFAS may be removed if foam is continuously collected with potential to reduce waste volume under economic barriers for current destructive technologies.

Bending performance of cross-laminated timber constructed from fibre-managed Eucalyptus nitens under short-term and long-term serviceability loads

AbstractCross-laminated timber (CLT) has become a notable building material due to its structural efficiency, reliability and sustainability. In this study, the bending performance of three-layered CLT constructed from fibre-managed Eucalyptus nitens (E. nitens) was investigated under short-term and long-term loadings. Linear-elastic four-point bending testing was used to determine the maximum serviceability loading capacity before they reached the suggested deflection limits. A pilot study was conducted to investigate the creep behaviour of E. nitens CLT through long-term bending tests in a controlled environmental room. The study suggested that E. nitens CLT has higher serviceability loading capacity and lower creep ratio compared to CLT made from strength-class C24 spruce. The investigations of various configurations of E. nitens CLT panels based on structural grades implemented in top, cross, and bottom layers have revealed different short-term and long-term bending performances. The grade of transverse layers has been found to be the most important factor in improving the bending creep performance of E. nitens CLT. Two modelling equations were employed to perform curve fitting on the experimental creep ratio with time. The conventional power-law modelling tends to underestimate the longer-term creep ratio when compared to a recently developed nonlinear regression modelling equation that takes environmental conditions into account. The mean estimated creep ratio after 50 years was 1.77 for E. nitens CLT, and 1.89 for the C24 spruce CLT. The present study is a pilot investigation to increase the understanding of performance of the newly developed CLT made from fibre-managed plantations E. nitens, with particular emphasis on its creep behaviour. The results of this study provide valuable contributions for future research in this field, and ongoing commercial production of E. nitens CLT.

Characterization of aqueous foams of alkyl polyglycoside, GreenZyme, alpha-olefin sulfonate, and cetyltrimethylammonium bromide in the presence of divalent ions

In this study, the impacts of divalent ions (calcium and magnesium) on aqueous foam stability and its rheological properties are investigated. A biodegradable surfactant of alkyl polyglycoside, (APG) and a commercial enzyme (GreenZyme, GZ) are used and their performance were compared with synthetic surfactants of alpha-olefin sulfonate (AOS) and cetyltrimethylammonium bromide (CTAB). The findings of the study revealed that the stability of all foams decreased with increasing concentrations of divalent ions, GZ recorded the lowest foam stability in the presence of the two ions and precipitation occurred in the AOS solution. On the other hand, foams generated by APG achieved the highest stability and the foams generated by CTAB showed the second highest stability among the foaming agents. Through rheological analyses, APG and CTAB exhibited shear thinning behaviour and their behaviour were modelled using a power law model in which the model can incorporate the effects of temperature and salinity.

Impact of Impeller Speed Adjustment Interval on Hemolysis Performance of an Intravascular Micro-Axial Blood Pump.

In recent years, intravascular micro-axial blood pumps have been increasingly used in the treatment of patients with cardiogenic shock. The flow rate of such blood pumps requires adjustment based on the patient's physiological condition. Compared to a stable flow state with fixed rotation speed, adjusting the speed of blood pump impeller to alter flow rate may lead to additional hemolysis. This study aimed at elucidating the relationship between adjusting interval of a blood pump's impeller speed and the hemolysis index. By comparing simulation results with P-Q characteristic curves of the blood pump measured by experiments, the accuracy of the blood pump flow field simulation model was confirmed. In this study, a drainage tube was employed as the device analogous to an intravascular micro-axial blood pump for achieving similar shear stress levels and residence times. The hemolysis finite element prediction method based on a power-law model was validated through hemolysis testing of porcine blood flow through the drainage tube. The validated models were subsequently utilized to investigate the impact of impeller speed adjusting intervals on hemolysis in the blood pump. Compared to steady flow, the results demonstrate that the hemolysis index increased to 6.3% when changing the blood pump flow rate from 2 L/min to 2.5 L/min by adjusting the impeller speed within 0.072 s. An adjustment time of impeller speed longer than 0.072 s can avoid extra hemolysis when adjusting the intravascular micro-axial blood pump flow rate from 2 L/min to 2.5 L/min.

GRB 210323A: Signature of Long-lasting Lifetime of Supra-massive Magnetar as the Central Engine from the Merger of Binary Neutron Star

Theoretically, a supra-massive neutron star or magnetar may be formed after the merger of binary neutron stars. GRB 210323A is a short-duration gamma-ray burst (GRB) with a duration of lasting ∼1 s. The light curve of the prompt emission of GRB 210323A shows a signal-peaked structure and a cutoff power-law model can adequately fit the spectra with E p = 1826 ± 747. More interestingly, it has an extremely long-lasting plateau emission in the X-ray afterglow with a duration of ∼104 s, and then follows a rapid decay with a decay slope ∼3.2. This temporal feature is challenging by invoking the external shock mode. In this paper, we suggest that the observed long-lasting X-ray plateau emission is caused by the energy injection of dipole radiation from supra-massive magnetar, and the abrupt decay following the long-lasting X-ray plateau emission is explained by supra-massive magnetar collapsing into a black hole. It is the short GRB (SGRB) with the longest X-ray internal plateau emission powered by a supra-massive neutron star. If this is the case, one can estimate the physical parameters of a supra-massive magnetar, and compare with other SGRBs. We also discuss the possible gravitational-wave emission, which is powered by a supra-massive magnetar and its detectability, and the possible kilonova emission, which is powered by r-process and magnetar spin-down to compare with the observed data.

Experimental investigations and material modeling of an elastomer jaw coupling

Abstract This work investigates the hyper-viscoelastic behavior of a thermoplastic polyurethane IROGRAN A 92 E 5670 FCM used in the gear rim of a jaw coupling. The aim is to provide the material parameters for the modeling of jaw couplings in engineering tasks. Uniaxial compression tests were conducted at various temperatures and loading speeds to fit a hyper-viscoelastic material model. The material model uses the Yeoh free energy and the power law model with one Maxwell element. The parametrized material model showed very good results in comparison to experimental data. In addition, the influence of friction on the experiments was modeled, investigated, and discussed. Further component tests for a jaw coupling of size 28 were conducted with two different specimen types. The original gear rim and a modified gear rim with central boreholes for integrated sensors were used in the test. The influence of such a modification was investigated with four different loading cases, focusing on the torsion-torque characteristic and the relative damping. These component tests enable the validation of numerical models of jaw couplings.

Comparison of four rheological models for estimating viscosity and rheological parameters of microwave treated Basil seed gum

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.

CFD simulation of arterial hypotension in a left anterior coronary artery section with potential clinical relevance

ABSTRACT Atherosclerosis is a complex cardiovascular condition characterised by the buildup of fatty deposits, known as plaques, on the inner walls of arteries. Stenosis occurs when the narrowing of an artery becomes particularly pronounced due to the accumulation of plaque. This narrowed lumen leads to significant pressure drops during blood flow, which may lead to decreased blood flow to the target tissues. The current study focuses on conducting computational fluid dynamic (CFD) simulations of blood flow within a linear segment of the LAD (Left anterior descending) coronary artery, subject to differing degrees of atherosclerotic stenosis. The simulations are performed using COMSOL Multiphysics 5.6®. The study has computed pressure drops by considering the laminar flow of blood as a two-phase non-Newtonian fluid. The rheological characteristics have been modelled using the Carreau Yasuda model. It considers varying stenosis severities ranging from 10% to 90%, coupled with blood velocities spanning from 0.07 m/s to 0.2 m/s. Additionally, the findings have been compared to results generated using the Power Law model and Casson-Papanastasiou model for blood rheology. The pressure drop within the stenosed section has been correlated with stenosis percentages through power law models.

On the Nature of the Radio Calibrator and Gamma-Ray Emitting NLS1 Galaxy 3C 286 and Its Multiwavelength Variability

The quasar 3C 286, a well-known calibrator source in radio astronomy, was found to exhibit exceptional multiwavelength properties. Its rich and complex optical emission-line spectrum revealed its narrow-line Seyfert 1 (NLS1) nature. Given its strong radio emission, this makes 3C 286 one of the radio-loudest NLS1 galaxies known to date. 3C 286 is also one of very few known compact steep-spectrum (CSS) sources detected in the gamma-ray regime. Observations in the X-ray regime, rarely carried out so far, revealed evidence for variability, raising the question whether it is driven by the accretion disk or jet. 3C 286 is also well known for its damped Lyman alpha system from an intervening absorber at z = 0.692, triggering a search for the corresponding X-ray absorption along the line-of-sight. Here, we present new observations in the radio, X-ray, optical, and UV bands. The nature of the X-ray variability is addressed. Spectral evidence suggests that it is primarily driven by the accretion disk (not the jet), and the X-ray spectrum is well fit by a powerlaw plus soft excess model. The radio flux density and polarization remain constant at the Effelsberg telescope resolution, reconfirming the use of 3C 286 as radio calibrator. The amount of reddening/absorption along the line-of-sight intrinsic to 3C 286 is rigorously assessed. None is found, validating the derivation of a high Eddington ratio (L/LEdd ∼ 1) and of the very high radio-loudness index of 3C 286. Based on the first deep Chandra image of 3C 286, tentative evidence for hard X-ray emission from the SW radio lobe is reported. A large variety of models for the gamma-ray emission of 3C 286 are briefly discussed.

Research on the bearing creep characteristics and constitutive model of gangue filling body

The creep characteristics and potential deformation patterns of gangue backfill material are crucial in backfill mining operations. This study utilizes crushed gangue from the Gangue Yard in Fuxin City as the research material. An in-house designed, large-scale, triaxial gangue compaction test system was used. Triaxial compaction creep tests were conducted on gangue materials with varying particle size distributions. Analysis was performed based on different particle sizes, stresses, and confinement pressures. The study investigates the creep characteristics of the gangue under different conditions and explores the underlying causes. It reveals the relationship between the creep deformation of gangue materials and the passage of time. Mathematical methods are applied to develop a triaxial compaction creep power law model for gangue backfill materials. Finally, the creep results are fitted using an empirical formula approach.

Modeling of anti-spike IgG and neutralizing antibody waning after anti-SARS-CoV-2 mRNA vaccination

At present, mRNA-based vaccines against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are being administered on a global scale. While the efficacy of mRNA vaccines has been demonstrated, several unknowns remains. For example, as the number of booster vaccinations increases, there are uncertainties regarding how long effects of a vaccine will last and how much individual variability exists. In this study, to predict the duration of vaccine efficacy, we modeled the kinetics of antibody levels for each SARS-CoV-2 vaccination dose, incorporating predictive intervals to estimate the duration of vaccine efficacy and to account for variability among individuals. A total of 3,059 serum samples from 1,346 participants were assayed to quantify IgG antibodies specific for the S1 subunit of the S protein (anti-S1 IgG) and neutralizing antibody activities against SARS-CoV-2. A power law model was used to simulate the decay of antibody titers following vaccination, and models were constructed to assess antibody level kinetics after the second, third, fourth, and fifth vaccinations. The models assumed that booster vaccinations would significantly reduce the decline in anti-S antibody and neutralizing antibody levels, resulting in levels being maintained for a longer period. No significant differences in the decay rate of antibody levels were observed among age groups, yet the peak titers of antibody levels were significantly higher in the ≤ 39 age group than in the ≥ 60 age group following the second vaccination; these differences were not observed after the third and fourth vaccinations. The modeling of antibody level kinetics after vaccination is considered to be useful for understanding the immune status of mRNA vaccine recipients.

Dynamic constitutive model of Fe–Cr–Ni stainless steel based on isothermal true stress-strain curves

Austenitic Fe–Cr–Ni stainless steel is widely used in aviation, chemistry, energy, due to its excellent properties of high-temperature performance. In this study, the splitting Hopkinson pressure bar with high-temperature system was employed to evaluate the dynamic mechanical properties of Fe–Cr–Ni stainless steel. The true stress-strain curves were obtained under varying conditions, including variable strains, strain rates and temperatures. The true stress increases and levels off as the true strain increases, while increases as the strain rate increases, but decreases sharply as the deformation temperature rises. The deformation temperature is consist of healing temperature and adiabatic temperature. The adiabatic temperature rise related to the specific heat capacity was calculated. The actual deformation temperatures were calculated under different strains by combining the true stress-strain curves. The true stress-strain curve under variable temperature was corrected to the stress-strain curve under isothermal state by using the thermal softening rate, which decoupled the strain and temperature. The Power-Law and Johnson-Cook constitutive models were fitted based on the real stress-strain isothermal curve. The fitting accuracy of Power-Law model was 1.61% for different strain rates at room temperature in average, 3.51% for fixed strain rate at different temperatures. While the fitting accuracy of Johnson-Cook model was 2.94% for different strain rates at room temperature in average, 6.18% for fixed strain rate at different temperatures.

Time Delay of Fast Radio Burst Population with Respect to the Star Formation History

In spite of significant progress in the research of fast radio bursts (FRBs) in recent decades, their origin is still under extensive debate. Investigation of the population of FRBs can provide new insight into this interesting problem. In this paper, based on the first Canadian Hydrogen Intensity Mapping Experiment (CHIME)/FRB catalog, we construct a Bayesian framework to analyze the FRB population, with the selection effect of the CHIME telescope being properly taken into account. The energy function is modeled as the power law with an exponential cutoff. Four redshift distribution models are considered, i.e., the star formation history (SFH) model, and three time-delayed models (Gaussian delay, log-normal delay, and power-law delay). The free parameters are simultaneously constrained using the Bayesian inference method, and the Bayesian information criterion (BIC) is used in model comparison. According to the BIC, the log-normal delay model fits the data best. The power-law delay model and Gaussian delay model can also give reasonable fits, although they are not as good as the log-normal delay model. However, the SFH model is strongly disfavored compared with the three time-delayed models. The energy function is tightly constrained and is almost independent of the redshift models, with the best-fitting power-law index α ≈ 1.8 and cut-off energy log(Ec/erg)≈42 . The FRB population shows on average a 3 ∼ 5 billion yr time delay with respect to the SFH. Therefore, the hypothesis that the FRB population traces the SFH is conclusively ruled out.

Sensitivity of GNSS to vertical land motion over Europe: effects of geophysical loadings and common-mode errors

We perform a statistical sensitivity analysis on a parametric fit to vertical daily displacement time series of 244 European Permanent GNSS stations, with a focus on linear vertical land motion (VLM), i.e., station velocity. We compare two independent corrections to the raw (uncorrected) observed displacements. The first correction is physical and accounts for non-tidal atmospheric, non-tidal oceanic and hydrological loading displacements, while the second approach is an empirical correction for the common-mode errors. For the uncorrected case, we show that combining power-law and white noise stochastic models with autoregressive models yields adequate noise approximations. With this as a realistic baseline, we report improvement rates of about 14% to 24% in station velocity sensitivity, after corrections are applied. We analyze the choice of the stochastic models in detail and outline potential discrepancies between the GNSS-observed displacements and those predicted by the loading models. Furthermore, we apply restricted maximum likelihood estimation (RMLE), to remove low-frequency noise biases, which yields more reliable velocity uncertainty estimates. RMLE reveals that for a number of stations noise is best modeled by a combination of random walk, flicker noise, and white noise. The sensitivity analysis yields minimum detectable VLM parameters (linear velocities, seasonal periodic motions, and offsets), which are of interest for geophysical applications of GNSS, such as tectonic or hydrological studies.

The Peculiar Precursor of a Gamma-Ray Burst from a Binary Merger Involving a Magnetar

The milestone discovery of GW170817-GRB 170817A-AT 2017gfo has shown that gravitational waves (GWs) could be produced during the merger of a neutron star–neutron star/black hole and that in electromagnetic (EM) waves, a gamma-ray burst (GRB) and a kilonova (KN) are generated in sequence after the merger. Observationally, however, EM properties before the merger phase are still unclear. Here we report a peculiar precursor in a KN-associated long-duration GRB 211211A, providing evidence of the EM before the merger. This precursor lasts ∼0.2 s, and the waiting time between the precursor and the main burst is ∼1 s, comparable to that between GW170817 and GRB 170817A. The spectrum of the precursor could be well fit with a nonthermal cutoff power-law model instead of a blackbody. In particular, a ∼22 Hz quasiperiodic oscillation candidate (∼3σ) is detected in the precursor. These temporal and spectral properties indicate that this precursor is probably produced by a catastrophic flare accompanied with magnetoelastic or crustal oscillations of a magnetar in a binary compact merger. The strong magnetic field of the magnetar can also account for the prolonged duration of GRB 211211A. However, it poses a challenge to reconcile the rather short lifetime of a magnetar with the rather long spiraling time of a binary neutron star system only by the GW radiation before the merger.

Positive Bias Temperature Instability in SiC-Based Power MOSFETs.

This paper investigates the threshold voltage shift (ΔVTH) induced by positive bias temperature instability (PBTI) in silicon carbide (SiC) power MOSFETs. By analyzing ΔVTH under various gate stress voltages (VGstress) at 150 °C, distinct mechanisms are revealed: (i) trapping in the interface and/or border pre-existing defects and (ii) the creation of oxide defects and/or trapping in spatially deeper oxide states with an activation energy of ~80 meV. Notably, the adoption of different characterization methods highlights the distinct roles of these mechanisms. Moreover, the study demonstrates consistent behavior in permanent ΔVTH degradation across VGstress levels using a power law model. Overall, these findings deepen the understanding of PBTI in SiC MOSFETs, providing insights for reliability optimization.

Development of a Probabilistic Correlation between the Gamma Ray Index and Shale Volume Factor to Improve Resource Estimation for the Niger Delta Basin, Nigeria

The shale volume factor is among the critical petrophysical parameters for reservoir characterization and formation evaluation. Inaccurate estimates of the shale volume factor can lead to poor reserves or resource estimates and wrong business decisions. While the current industry standard is to estimate the shale volume factor from the gamma ray logs using the concept of the gamma ray index, a relationship between the shale volume factor and the gamma-ray index needs to be established for any region/basin under consideration. For most applications in the Niger Delta Basin, a linear relationship is often assumed. However, there is no proven relationship between the shale volume factor and the gamma-ray index for the formations in the Niger Delta Basin. This paper proposes a new shale volume factor prediction correlation for the Niger Delta Basin in Nigeria. The correlation development is based on establishing a relationship between the shale volume factor obtained from cores and the gamma ray index obtained from petrophysical logs for over thirty wells drilled across the Niger Delta Basin. The results show that the relationship between the shale volume factor and the gamma-ray index is not linear as often assumed but a power law model. The new probabilistic correlation predicts lower shale volume factors than the linear model for all ranges of the gamma-ray index. This recent correlation will significantly impact how the hydrocarbon resources and reserves are quantified in the Niger Delta Basin.

Viscosity-model-independent generalized Reynolds number for laminar pipe flow of shear-thinning and viscoplastic fluids

Understanding the flow dynamics of non-Newtonian fluids is crucial in various engineering, industrial, and biomedical applications. However, the existing generalized Reynolds number formulations for non-Newtonian fluids have limited applicability due to their dependencies on their specific viscosity models. In this study, we propose a new viscosity-model-independent generalized Reynolds number formulation for laminar pipe flow. The proposed method is based on the direct adaptation of the measurement principles of rotational viscometers for wall shear rate estimation. We assess the accuracy of this proposed formulation for power-law and Carreau-Yasuda viscosity models through robust friction factor experiments. The experimental results demonstrate the applicability and effectiveness of the proposed viscosity-model-independent Reynolds number, as the measured friction factor data align closely with our Reynolds number predictions. Furthermore, we compare the accuracy of our Reynolds number formulation against established generalized Reynolds formulations for pure shear-thinning (Carreau-Yasuda) and viscoplastic (Herschel-Bulkley-extended) models. The results of the comparative analysis confirm the reliability and robustness of this generalized Reynolds number in characterizing and interpreting flow behavior in systems with visco-inelastic non-Newtonian fluids. This unified generalized Reynolds number formulation presents new and significant opportunities for precise pipe flow characterization and interpretation as it is applicable to any visco-inelastic (time-independent) viscosity model without requiring additional derivations.