scholarly journals Cluster-associated viscosity model and methods for determining its parameters

2020 ◽  
Vol 2 (313) ◽  
pp. 27-37
Author(s):  
A. M. Makasheva ◽  
Keyword(s):  
Viscous Flow ◽  
Hierarchical Cluster ◽  
Reference Points ◽  
Viscosity Model ◽  
Liquid Lithium ◽  
Model Parameters ◽  
Viscosity Data ◽  
Thermal Barriers ◽  
Degree Of Association ◽  
Processing Techniques

A detailed development of a hierarchical cluster-associate mathematical viscosity model is shown. The model is based on the equilibrium Boltzmann’s distribution and, therefore, is regarded as a chaosensitive property of a fluid inherent in it not only in motion but also at rest. In this model, the key characteristics are chaotic thermal barriers at the melting and boiling points, in connection with which the behavior of a liquid is determined by the action of three energy classes of particles – crystal-mobile, liquid-mobile, and vapor-mobile. An important single indicator in the new model depends on temperature and makes sense of the degree of association of clusters of crystal-mobile particles. The assignment of the activation energy of the viscous flow of melts determined by the Frenkel’s equation to the degree of cluster association gives a constant value commensurate with the binding energy of the van der Waals particle attractive forces. On this basis, the authors hypothesized that a viscous flow occurs due to the destruction of cluster associates while preserving the clusters themselves. To adapt the cluster-associate model to experimental data, certain data processing techniques have been developed to identify unknown model parameters. All calculations are illustrated on liquid lithium and have shown their high adequacy. Also added is a method for processing viscosity data using the entire set of viscosity data while maintaining two reference points and processing the rest to determine the degree of aggregation of associates.

A Continuous and Predictive Viscosity Model Coupled to a Microemulsion Equation of State

SPE Journal ◽  
2019 ◽  
Vol 25 (03) ◽  
pp. 1070-1081
Author(s):  
Pooya Khodaparast ◽  
Russell T. Johns
Keyword(s):  
Equation Of State ◽  
Phase Behavior ◽  
Carbon Number ◽  
Viscosity Model ◽  
Model Parameters ◽  
Viscosity Data ◽  
Average Curvature ◽  
Three Phase ◽  
Percolation Thresholds ◽  
Brine Salinity

Summary Surfactant floods can attain high oil recovery if optimal conditions with ultralow interfacial tensions (IFT) are achieved in the reservoir. A recently developed equation-of-state (EoS) phase-behavior net-average-curvature (NAC) model based on the hydrophilic-lipophilic difference (HLD-NAC) has been shown to fit and predict phase-behavior data continuously throughout the Winsor I, II, III, and IV regions. The state-of-the-art for viscosity estimation, however, uses empirical nonpredictive based on of fits to salinity scans, even though other parameters change, such as the phase number and compositions. In this paper, we develop the first-of-its-kind microemulsion viscosity model that gives continuous viscosity estimates in composition space. This model is coupled to our existing HLD-NAC phase-behavior EoS. The results show that experimentally measured viscosities in all Winsor regions (two- and three-phase) are a function of phase composition, temperature, pressure, salinity, and the equivalent alkane carbon number (EACN). More specifically, microemulsion viscosities associated with the three-phase invariant point have an M shape as formulation variables change, such as from a salinity scan. The location and magnitude of viscosity peaks in the M are predicted from two percolation thresholds after tuning to viscosity data. These percolation thresholds as well as other model parameters change linearly with EACN and brine salinity. We also show that the minimum viscosity in the M shape correlates linearly with EACN or the viscosity ratio. Other key parameters in the model are also shown to linearly correlate with the EACN and brine salinity. On the basis of these correlations, two- and three-phase microemulsion viscosities are determined in five-component space (surfactant, two brine components, and two oil components) independent of flash calculations. Phase compositions from the EoS flash calculations are entered into the viscosity model. Fits to experimental data are excellent, as well as viscosity predictions for salinity scans not used in the fitting process.

Rheological modelling of fresh human faeces

2014 ◽  
Vol 4 (3) ◽  
pp. 484-489 ◽  
Author(s):  
S. M. Woolley ◽  
C. A. Buckley ◽  
J. Pocock ◽  
G. L. Foutch
Keyword(s):  
Fluid Dynamics ◽  
Reasonable Agreement ◽  
Model Parameters ◽  
Viscosity Data ◽  
Initial Screening ◽  
Human Faeces ◽  
Shear Thinning Fluids ◽  
Treatment Processes ◽  
Rheological Modelling ◽  
Generate Model

An analysis of viscosity data from sets of raw data on the shear rheological properties of fresh human faeces was performed to generate model constants that can be used for the design of faecal treatment processes. The models selected are standard choices in computational fluid dynamics software for shear-thinning fluids. Initial screening for model selection was based on a literature review of similarly viscous materials. Results showed reasonable agreement with Power Law (PL). PL model parameters were proposed for fresh human faeces and correlated against sample properties. A PL model for shear stress as a function of moisture content was proposed.

Cluster Analysis of Dynamic Parameters of Gene Expression

2003 ◽  
Vol 01 (03) ◽  
pp. 447-458 ◽  
Author(s):  
Xiwei Wu ◽  
T. Gregory Dewey
Keyword(s):  
Gene Expression ◽  
Cell Cycle ◽  
Cluster Analysis ◽  
Hierarchical Cluster ◽  
Specific Model ◽  
Model Parameters ◽  
Dynamic Parameters ◽  
Clustering Methods ◽  
Transition Matrices ◽  
Great Utility

Cluster analysis has proven to be a valuable statistical method for analyzing whole genome expression data. Although clustering methods have great utility, they do represent a lower level statistical analysis that is not directly tied to a specific model. To extend such methods and to allow for more sophisticated lines of inference, we use cluster analysis in conjunction with a specific model of gene expression dynamics. This model provides phenomenological dynamic parameters on both linear and non-linear responses of the system. This analysis determines the parameters of two different transition matrices (linear and nonlinear) that describe the influence of one gene expression level on another. Using yeast cell cycle microarray data as test set, we calculated the transition matrices and used these dynamic parameters as a metric for cluster analysis. Hierarchical cluster analysis of this transition matrix reveals how a set of genes influence the expression of other genes activated during different cell cycle phases. Most strikingly, genes in different stages of cell cycle preferentially activate or inactivate genes in other stages of cell cycle, and this relationship can be readily visualized in a two-way clustering image. The observation is prior to any knowledge of the chronological characteristics of the cell cycle process. This method shows the utility of using model parameters as a metric in cluster analysis.

scholarly journals Research on Decision-Making Behavior of Discretionary Lane-Changing Based on Cumulative Prospect Theory

2020 ◽  
Vol 2020 ◽  
pp. 1-16
Author(s):  
Xueqin Long ◽  
Liancai Zhang ◽  
Shanshan Liu ◽  
Jianjun Wang
Keyword(s):  
Decision Making ◽  
Prospect Theory ◽  
Real Data ◽  
Cumulative Prospect Theory ◽  
Reference Points ◽  
Model Parameters ◽  
Lane Changing ◽  
Actual Observation ◽  
The Difference ◽  
Lane Keeping

In this paper, the decision-making model of discretionary lane-changing is established using cumulative prospect theory (CPT). Through analyzing the vehicles’ dynamic running states, safety spacing calculating approaches for discretionary lane-changing and lane-keeping have been put forward firstly. Then, based on CPT, a lane-changing decision model with accelerating space as its utility is proposed by estimating the difference between actual spacings and the safety spacings for discretionary lane-changing as well as lane-keeping. In order to calculate the utility of discretionary lane-changing, dynamic reference points and a parameter representing driver’s risk preference are introduced into the model. With the real data collected from an urban expressway, the distribution of discretionary lane-changing duration is analyzed, and the model parameters are also calibrated. Furthermore, the applicability of the model is evaluated by comparing with the actual observation and random unity model. Finally, the sensitivity analysis of the model is carried out, that is, assessing the influence degree of each variable on the decision result. The study reveals that the CPT-based model can describe discretionary lane-changing behavior more accurately, which consider drivers’ risk-aversion during decision-making.

scholarly journals Life-history characteristics of Pseudoplatystoma metaense (Teleostei: Siluriformes: Pimelodidae) from the northwestern Orinoco River Basin

2018 ◽  
Vol 16 (1) ◽  
Author(s):  
Alfredo Pérez ◽  
Nidia Noemí Fabré
Keyword(s):  
River Basin ◽  
Market Price ◽  
Total Mortality ◽  
Flood Pulse ◽  
Reference Points ◽  
Model Parameters ◽  
Population Parameters ◽  
Zone Formation ◽  
Orinoco River ◽  
Marginal Increment

ABSTRACT The tiger shovelnose catfish (Pseudoplatystoma metaense) identified in literature prior to 2007 as P. tigrinum is the most important catfish species in the Orinoco River fishery, because of its abundance and high market price. The aim of this study was to obtain age, growth and population parameters of the of tiger shovelnose catfish. A total of 2,183 catfish, were sampled during 1996-2003 from the commercial fishery of the northwestern Orinoco River Basin in Venezuela, and were aged by examination of otoliths. Validation of otolith annuli was achieved with marginal increment analysis. Results suggest that, the opaque and translucent zones of otoliths were formed once per year. Length-weight relation and the von Bertalanffy growth model parameters were used to evaluate growth and other population parameters. A strong link between the annual flood pulse and opaque zone formation was confirmed in tiger shovelnose catfish. The total mortality (Z) and natural mortality (M) were estimated. Based in the reference points for optimal and limit fishing mortality rates (F opt and F limit ) this species is exploited above optimum levels. We thus recommend a closed fishing season during their seasonal reproduction, and establishment of a system of fish refuges to help sustain the population.

Eggs-per-recruit model for management of the California market squid (Loligo opalescens) fishery

2005 ◽  
Vol 62 (7) ◽  
pp. 1640-1650 ◽  
Author(s):  
Michael R Maxwell ◽  
Larry D Jacobson ◽  
Ramon J Conser
Keyword(s):  
Mortality Rate ◽  
Egg Laying ◽  
Reference Points ◽  
Model Parameters ◽  
Natural Mortality ◽  
Fishing Mortality ◽  
Loligo Opalescens ◽  
Maturation Rate ◽  
Sampling Procedures ◽  
Yield Per Recruit

We develop a per-recruit model for the management of the California market squid (Loligo opalescens) fishery. Based on recent confirmation of determinate fecundity in this species, we describe how catch fecundity (i.e., eggs remaining in the reproductive tracts of harvested females) can be used to simultaneously infer fishing mortality rate along with management reference points such as yield-per-recruit, spawned eggs-per-recruit, and proportional egg escapement. Rates of mortality and egg laying have important effects on these reference points. Somewhat surprisingly, increasing the rate of natural mortality decreased spawned eggs-per-recruit while increasing proportional egg escapement. Increasing the rate of egg laying increased both spawned eggs-per-recruit and egg escapement. Other parameters, such as the maturation rate and gear vulnerability of immature females, affected the reference points. In actual practice, the influence of these parameters for immature squid may go undetected if immature squid are excluded from analysis of the catch. Application of this model to routine management is feasible but requires refinement of sampling procedures, biological assumptions, and model parameters. This model is useful because it is grounded on empirical data collected relatively inexpensively from catch samples (catch fecundity) while allowing for the simultaneous calculation of instantaneous fishing mortality rate and egg escapement.

Ion Pair Formation in NaNO3/D2O Solutions: Raman and Infrared Spectra, Partial Molal Volumes, Conductance, and Viscosity

1972 ◽  
Vol 50 (18) ◽  
pp. 2951-2962 ◽  
Author(s):  
J. D. Riddell ◽  
D. J. Lockwood ◽  
D. E. Irish
Keyword(s):  
Deuterium Oxide ◽  
Ion Pairs ◽  
Ion Pair ◽  
Viscosity Data ◽  
Exchange Equilibrium ◽  
Partial Molal Volume ◽  
Molal Volume ◽  
Vibrational Assignments ◽  
Laser Raman ◽  
Degree Of Association

Laser Raman and infrared vibrational spectra of solutions of NaNO3 in deuterium oxide reveal the presence of both [Formula: see text] ion pairs and solvated nitrate ions. The degree of association has been measured. The concentration quotients are remarkably independent of concentration and almost equal to the thermodynamic association constant, 0.060 ± 0.006 kg mol−1 at 25.0 °C. The latter quantity was obtained by an extrapolation procedure, taking account of the activity coefficients. Values are reported for the activity coefficient of the ion pair. Interpretation is also considered in terms of a place-exchange equilibrium involving the solvent. Vibrational assignments are made to the two forms of nitrate ion present. Density, partial molal volume, conductance, and viscosity data are also presented and discussed in terms of the reported constitution.

scholarly journals Study of Thermodynamic and Transport Properties of Glycine, Diglycine, and Triglycine in Aqueous Tartrazine at Different Temperatures

2009 ◽  
Vol 64 (11) ◽  
pp. 758-764 ◽  
Author(s):  
Anwar Ali ◽  
Rajan Patel ◽  
Shahjahan Khan ◽  
Vidiksha Bhushan
Keyword(s):  
Viscous Flow ◽  
Activation Parameters ◽  
Partial Molar Volumes ◽  
Molar Refraction ◽  
Viscosity Data ◽  
Molar Volumes ◽  
Viscosity Coefficients ◽  
Different Temperatures ◽  
Refractive Index Data ◽  
Amino Acid Glycine

The densities (ρ), viscosities (η), and refractive indices (nD) of (0.01, 0.05, 0.10, 0.15, and 0.20 m) amino acid, glycine, and peptides, diglycine and triglycine in 0.01 m aqueous tartrazine solution were determined at 288.15, 293.15, 298.15, 303.15, 308.15, and 313.15 K. The density data were utilized to evaluate apparent molar volumes (φv) which, in turn, were used to determine partial molar volumes (φv ◦) using Masson’s equation. The transfer volumes were also calculated. The viscosity data were analyzed using the Jones-Dole equation to determine the viscosity coefficients and the activation parameters. The activation parameters of viscous flow were obtained to throw light on the mechanism of viscous flow. The molar refraction was calculated using the refractive index data. The results were interpreted in the light of ion-ion, ion-nonpolar, and nonpolar-nonpolar interactions and the effect of increasing hydrophobicity as we move from glycine to triglycine on these interactions in presence of the dye tartrazine was also investigated.

scholarly journals A phenomenological theory-based viscosity model for shear thickening fluids

2021 ◽  
Author(s):  
Kun Lin ◽  
Jiapeng Qi ◽  
Hongjun Liu ◽  
Minghai Wei ◽  
Hua Yi Peng
Keyword(s):  
Experimental Data ◽  
Impact Resistance ◽  
Shear Thickening ◽  
Phenomenological Theory ◽  
Logistic Function ◽  
Viscosity Model ◽  
Model Parameters ◽  
Shear Rates ◽  
Marquardt Algorithm ◽  
Shear Thickening Fluids

Abstract A viscosity model for shear thickening fluids (STFs) based on phenomenological theory is proposed. The model considers three characteristic regions of the typical material properties of STFs: a shear thinning region at low shear rates, followed by a sharp increase in viscosity above the critical shear rate, and subsequently a significant failure region at high shear rates. The typical S-shaped characteristic of the STF viscosity curve is represented using the logistic function, and suitable constraints are applied to satisfy the continuity of the viscosity model. Then, the Levenberg–Marquardt algorithm is introduced to fit the constitutive model parameters based on experimental data. Verification against experimental data shows that the model can predict the viscosity behavior of STF systems composed of different materials with different mass concentrations and temperatures. The proposed viscosity model provides a calculation basis for the engineering applications of STFs (e.g., in increasing impact resistance and reducing vibration).

scholarly journals Quantitative modeling of regular retinal microglia distribution

2021 ◽  
Author(s):  
Yoshie Endo ◽  
Daisuke Asanuma ◽  
Shigeyuki Namiki ◽  
Kenzo Hirose ◽  
Akiyoshi Uemura ◽  
...  
Keyword(s):  
Model Simulation ◽  
Cell Movement ◽  
Cell Contact ◽  
Model Parameters ◽  
Regular Distribution ◽  
Cell Spacing ◽  
Process Formation ◽  
Direct Cell ◽  
The Central Nervous System ◽  
Processing Techniques

Microglia are resident immune cells in the central nervous system (CNS), showing a regular distribution. Advancing microscopy and image processing techniques have contributed to elucidating microglia’s morphology, dynamics, and distribution. However, the mechanism underlying the regular distribution of microglia remains to be elucidated. First, we quantitatively confirmed the regularity of the distribution pattern of microglial soma. Second, we formulated a mathematical model that includes factors that may influence regular distribution. Next, we experimentally quantified the model parameters (cell movement, process formation, and ATP dynamics). The resulting model simulation from the measured parameters showed that direct cell-cell contact is most important in generating regular cell spacing. Finally, we tried to specify the molecular pathway responsible for the repulsion between neighboring microglia.

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