Larson Model Research Articles

Applying Larson's Model To Assess the Quality of Two Translations of Antony Hope's Novel The Prisoner of Zenda into Arabic

This paper investigates the quality of two translations of Antony Hope's" Prisoner of Zenda" novel by applying Larson's model. This novel is rendered into Arabic by two translators in different places and times. The model has three significant criteria that can be employed to assess the quality of translated works including "accuracy, clarity and naturalness". They are considered important indicators of translation quality that can be used to assess the translation and assure that they are appropriately employed. To assess the two translations, the researchers apply each criterion to three excerpts taken from the novel and assess their translation and to what extent the source texts are appropriately rendered.

Using Economic Links between Firms to Detect Accounting Fraud

ABSTRACT We explore whether accounting fraud can be detected using the information of firms economically linked to a focal firm. Specifically, we examine whether customer information disclosed by a supplier firm, combined with customers’ accounting information, helps to detect the supplier’s revenue fraud. We first confirm the economic link between the supplier and customers by showing a strong positive correlation between the supplier’s sales growth and the growth rate of total customer purchases. We then introduce two variables based on customer accounting information—the discrepancy between supplier sales growth and customer purchase growth and customer excess purchases—and show that they are predictive of supplier revenue fraud. We conduct a battery of cross-sectional tests and generally find results to vary cross-sectionally in a predictable way. Finally, the out-of-sample tests indicate that adding the two variables to Dechow, Ge, Larson, and Sloan (2011) model increases fraud prediction accuracy. JEL Classifications: G14; M40; M41; M42.

Effect of ultrasound on the kinetics of anti-solvent crystallization of sucrose

The effect of ultrasound on the kinetics of anti-solvent crystallization of sucrose was studied. The influence of temperature, stirring rate, supersaturation and ultrasonic power on the anti-solvent crystallization of sucrose was investigated. The relationship between infrared spectral characteristic band of sucrose and supersaturation was determined with an online reaction analyzer. The crystal size distribution of sucrose was detected by a laser particle-size analyzer. Ultrasound accelerated the crystallization process, and had no impact on the crystal shape. Abegg, Stevens and Larson model was fitted to the experimental data, and the results were the following: At 298.15 K, the average size of crystals was 133.8 μm and nucleation rate was 4.87 × 109 m−3·s−1 without ultrasound. In an ultrasonic field, the average size was 80.5 μm, and nucleation rate was 1.18 × 1011 m−3·s−1. Ultrasound significantly reduced the average size of crystals and improved the nucleation rate. It was observed that the crystal size decreased with the increase of stirring rate in silent environment. When the stirring rate increased from 250 to 400 rpm, the average size decreased from 173.0 to 132.9 μm. However, the stirring rate had no significant impact on the crystal size in the ultrasonic field. In addition, the activation energy of anti-solvent crystallization of sucrose was decreased, and the kinetic constant of nucleation rate was increased due to the effect of ultrasound. In the ultrasonic field, the activation energy was reduced from 20422.5 to 790.5 J·mol−1, and the kinetic constant was increased from 9.76 × 102 to 8.38 × 108.

Infiltration-runoff model for layered soils considering air resistance and unsteady rainfall

AbstractA modified Green–Ampt model (MGAM) was proposed to simulate infiltrations into layered soil profiles with the entrapped air under unsteady rainfall conditions. To account for the effects of the air resistance, the saturation coefficient, actual water content, air bubbling pressure, and water bubbling pressure were introduced in the model. One-dimensional infiltration-runoff experiments were then conducted in multi-layered soil columns, under unsteady rainfall conditions, to evaluate the performance of the MGAM model. The cumulative infiltration, runoff rate, and water content of the soil, calculated by MGAM, were compared with the observed data and the results, calculated by the traditional Green–Ampt model (TGAM), the Bouwer Green–Ampt model (BGAM), and the Mein–Larson model (MLGAM), respectively. The results indicated that the cumulative infiltration, runoff rate, and soil water content, calculated by MGAM, were in better agreement with the observed results than previous models. A parameter sensitivity of MGAM was also analyzed. It was found that the sensitivity of the saturated coefficient was high in the first soil layer, and those of the air bubbling pressure and initial moisture deficit were high or medium in the first and second layers, while those of the other parameters were relatively low.

A Semi-Empirical SNR Model for Soil Moisture Retrieval Using GNSS SNR Data

The Global Navigation Satellite System-Interferometry and Reflectometry (GNSS-IR) technique on soil moisture remote sensing was studied. A semi-empirical Signal-to-Noise Ratio (SNR) model was proposed as a curve-fitting model for SNR data routinely collected by a GNSS receiver. This model aims at reconstructing the direct and reflected signal from SNR data and at the same time extracting frequency and phase information that is affected by soil moisture as proposed by K. M. Larson et al. This is achieved empirically through approximating the direct and reflected signal by a second-order and fourth-order polynomial, respectively, based on the well-established SNR model. Compared with other models (K. M. Larson et al., T. Yang et al.), this model can improve the Quality of Fit (QoF) with little prior knowledge needed and can allow soil permittivity to be estimated from the reconstructed signals. In developing this model, we showed how noise affects the receiver SNR estimation and thus the model performance through simulations under the bare soil assumption. Results showed that the reconstructed signals with a grazing angle of 5°–15° were better for soil moisture retrieval. The QoF was improved by around 45%, which resulted in better estimation of the frequency and phase information. However, we found that the improvement on phase estimation could be neglected. Experimental data collected at Lamasquère, France, were also used to validate the proposed model. The results were compared with the simulation and previous works. It was found that the model could ensure good fitting quality even in the case of irregular SNR variation. Additionally, the soil moisture calculated from the reconstructed signals was about 15% closer in relation to the ground truth measurements. A deeper insight into the Larson model and the proposed model was given at this stage, which formed a possible explanation of this fact. Furthermore, frequency and phase information extracted using this model were also studied for their capability to monitor soil moisture variation. Finally, phenomena such as retrieval ambiguity and error sensitivity were stated and discussed.

Kinetic analysis of nicotine desorption from silicon dioxide under non-isothermal conditions

Abstract The non-isothermal kinetics of nicotine desorption from precipitated silicon dioxide was investigated. The non-isothermal thermogravimetric curves of nicotine desorption at different heating rates (β = 5, 10 and 20 K/min) were recorded. The kinetics model of non-isothermal kinetics of nicotine desorption was determined by using the model-fitting and master-plot methods. It was found that non-isothermal nicotine desorption can mathematically describe by the theoretical kinetics model of phase – boundary controlled reaction (contracting volume, i.e., three dimensional shape) – R3. By applying the method of Kissinger and method of invariant kinetic parameters the values of kinetic parameters were determined. It was established that both applied method give almost identical kinetic parameters regardless their theoretical limitations. The dependence of activation energy on the degree of nicotine desorption was determined using the KAS method. It was found that the value of activation energy is independent on the degree of nicotine desorption. The effect of heating mode on the kinetic of nicotine desorption was analyzed. It was established that the type of heating mode (isothermal and non-isothermal) does not influence the mechanism of the formation of the activation complex nor the kinetics model of desorption. The increase in the values of kinetic parameters obtained for non-isothermal heating in comparison to the isothermal ones are explained with the Larson's model of selective transfer of energy.

Evaluate the nonlinear viscoelasticity of polyolefin melts using the Larson model

Nonlinear rheological properties of polyolefins have long been studied and predicted by using the Larson model with the damping function generally obtained from the stress relaxation measurements. In this study, we investigate the nonlinear rheological properties of high density polyethylene (HDPE) and polypropylene (PP) using the Larson model with damping functions obtained from either the dynamic frequency sweep or the stress relaxation test. Experimental measurements and their corresponding model predictions for the rheological parameters were then compared to evaluate the applicability of the Larson model to the nonlinear rheology, and the following conclusions could be achieved. The steady shear viscosity could be satisfactorily described by the Larson model with the damping functions obtained from the two different methods, except at shear rates higher than 103 s−1. The predicted first normal stresses also account for the measured data, except for those using the stress relaxation data showing a little deviation for the PP sample. In addition, the predictions for elongation viscosity are also in good agreement with the experimental results within the short range of elongation rate achieved in this work. POLYM. ENG. SCI., 54:2354–2361, 2014. © 2013 Society of Plastics Engineers

Estimation of viscosity coefficients and rheological functions of nanocrystalline cellulose aqueous suspensions

This paper presents a methodology to calculate different rheological functions and viscosity coefficients for lyotropic liquid crystals (LCs) using analytical calculations and experimental rheological data. By implementing Doi and Larson models for lyotropic nematic liquid crystals, the Leslie viscosity coefficients for nanocrystalline cellulose (NCC) aqueous suspensions have been calculated as a function of concentration of molecules per unit volume. The Landau viscosity coefficients from the symmetric viscous stress tensor have been calculated based on the mapping between Landau-de Gennes theory and the Leslie–Ericksen theory. Various parameters and dimensionless numbers from the Landau-de Gennes theory were calculated and related to experimental data. The validation was done using numerical simulations of the Landau-de Gennes equations for transient simple shear flow between parallel plates of 7 wt NCC aqueous suspensions and experimental rheological data. Apparent viscosity and shear stress from numerical simulations have been compared with the experimental results for the same concentration and found a good agreement. A cholesteric pattern was observed for low shear rates and flow-aligning regime for higher shear rates.

FEM–GIS based channel network model for runoff simulation in agricultural watersheds using remotely sensed data

Event based rainfall-runoff simulation is very important in water resources management. In this paper, an integrated watershed model considering important hydrological processes has been presented for the event based runoff simulation. Green–Ampt–Mein–Larson model has been used for the estimation of infiltration. For runoff estimation, kinematic wave equations are solved for a channel network using finite-element method. Remotely sensed data have been used for evaluating land use/land cover data. Geographical information systems have been used for the preparation of digital elevation model and various thematic maps. The developed integrated model has been applied to Harsul watershed in India. Calibration of the model has been carried out using six rainfall events and validation with four rainfall events. From the results, it is seen that the model is able to simulate the hydrographs with reasonable accuracy. A sensitivity analysis of the model has also been carried out. The developed model is useful for runoff estimation in small watersheds.

Effect of ultrasonic irradiation on crystallization kinetics of potassium dihydrogen phosphate

The ultrasound effect applied on potassium dihydrogen phosphate was investigated in a continuous crystallization system. The studied process variables were ultrasonic power (W) and residence time. The crystal size distributions of the final products obtained with and without ultrasonic power were determined and the data were evaluated by using modified form of Abegg, Stevens and Larson (ASL) model. The supersaturation limit decreased with ultrasonic waves and the crystal morphology was modified. The average crystal size decreased in the presence of ultrasonic power. An abrasive effect was observed at a high ultrasonic power input.

TESTING SOME PEDO-TRANSFER FUNCTIONS (PTFS) IN APULIA REGION

The knowledge of soil water retention vs. soil water matric potential is used to study irrigation and drainage schedules, soil water storage capacity (plant available water), solute movement, plant growth and water stress. The hydraulic soil properties measuring is expensive, laborious and takes too long time, so, frequently, matemathic models, called pedo-transfer functions (PTFs) are utilized to estimate hydraulic soil properties through soil chimical and phisical characteristics. Six pedo-transfer functions have been evaluated (Gupta & Larson, 1979; Rawls et al., 1982; De Jong et al., 1983; Rawls & Brakensiek, 1985; Saxton et al., 1986; Vereecken et al., 1989) by comparing estimated with measured soil moisture values at soil water matric potential of –33 and –1500 kPa of 361 soil samples collected from 185 pedons of Apulia Region (South Italy), having various combinations of particle-size distribution, soil organic matter content and bulk density. Accuracy of the soil moisture predictions have been evaluated by statistic indexes such as Weighted stantard error (WSEE), Mean Deviation (MD), Root Mean Squared Deviation (RMSD) and the determination coefficient (R2) between estimated and measured water retention values. The Rawls PTF model demostrated to have the lowest values of WSEE, MD and RMSD indexes (0.044, -0.007 and 0.059 m3 H2O m-3 soil, respectively) at –33 Kpa soil water matric potential (Field Capacity), while for estimating soil moisture at the Wilting Point (-1500 kPa) Rawls & Brakensiek model is adequate (WSEE, MD and RMSD of 0.034, -0.016 and 0.046 m3 H2O m-3 soil). De Jong, Saxton and Rawls & Brakensiek models, at –33 kPa soil water matric potential and Gupta & Larson and De Jong models at –1500 kPa soil water matric potential, showed the highest statistic errors.

Adsorption and Morphology Transition of Surfactants on Hydrophobic Surfaces: A Lattice Monte Carlo Study

In this work, we first show that there are only five independent interchange parameters in the surfactant-solvent-interface system in Larson's model, and then adsorption and morphology transition of surfactants on hydrophobic surfaces are studied by extensive lattice Monte Carlo simulations. In our simulations, we found that there exist six adsorbed morphologies: (1) premature admicelle, (2) hemisphere, (3) hemisphere-hemicylinder mixture, (4) wormlike hemicylinder, (5) perforated monolayer, and (6) monolayer. The surface morphologies and the amount of adsorption on hydrophobic surfaces are found to be affected obviously by two interchange parameters. One is the attractive interaction between tail groups and surface (chiTS), and the other is the solubility of head groups in bulk (chiHW). Phase diagrams in chiHW versus chiTS planes for surfactants with different hydrophobicities (chiTW) and for surfactants with different molecular structures are determined in this work, from which the transitions of surface morphologies and adsorption behaviors are discussed.

Complexation between a Macromolecule and an Amphiphile by Monte Carlo Technique

Using a simple modified version of Larson's model, we studied the complexation between a macromolecule and an amphiphile in a dilute range of concentrations. The main characteristic of amphiphile molecules, that is, the hydrophobicity of the tails and hydrophilicity of the heads, is used to model the self-assembling process. Contrary to the molecular thermodynamics approaches, no prior shape was considered for the aggregates and the system was allowed to choose the most stable structure. For true ensemble averaging, without any synthetic results, configurational bias Monte Carlo and reptation moves are used to produce a Markov chain of configurations. From the results, it is found that the macromolecule causes the clusters of surfactants to be formed at a concentration much lower than the critical micelle concentration. Furthermore, the shape of the clusters tends to be more spherical, which is in line with theory and experiments. From the results, it is learned how a polymer can change the behavior of an amphiphilic molecule. All of the results are in good qualitative agreement with experimental and molecular thermodynamics results. Furthermore, the model predicts network formation between bound clusters at high concentrations of the surfactant.

Relationship between Neck-in Phenomena and Rheological Properties in Film Casting

We numerically demonstrate that the ratio of uniaxial to planar elongational viscosity controls the neck-in phenomena of the casting polymer films, i.e., the decrease in film width value for both viscous and viscoelastic fluids. Quasi-three-dimensional numerical simulations of an isothermal film casting process were performed using a finite element method for two viscoelastic fluids using Larson and PTT models, purely-viscous non-Newtonian fluids using Cross model and Newtonian fluids. The increase in take-up velocity relative to that in extrusion showed particular film deformations of neck-in depending upon the rheological properties in the models. The results indicate that the film width is determined by the ratio of uniaxial to planar elongational viscosity rather than the extension-thickening nature in uniaxial elongation. The computations using different fluid models show that the viscosity ratio is universal for predicting the neck-in value of the stretching polymer films not only in viscoelastic but also in pure viscous fluids.

Coarse-grained computations for a micellar system

We establish, through coarse-grained computation, a connection between traditional, continuum numerical algorithms (initial value problems as well as fixed point algorithms), and atomistic simulations of the Larson model of micelle formation. The procedure hinges on the (expected) evolution of a few slow, coarse-grained mesoscopic observables of the Monte Carlo simulation, and on (computational) time scale separation between these and the remaining "slaved," fast variables. Short bursts of appropriately initialized atomistic simulation are used to estimate the (coarse grained, deterministic) local dynamics of the evolution of the observables. These estimates are then in turn used to accelerate the evolution to computational stationarity through traditional continuum algorithms (forward Euler integration, Newton-Raphson fixed point computation). This "equation-free" framework, bypassing the derivation of explicit, closed equations for the observables (e.g., equations of state), may provide a computational bridge between direct atomistic/stochastic simulation and the analysis of its macroscopic, system-level consequences.

Biaxial damping function of entangled monodisperse polystyrene melts: Comparison with the Mead–Larson–Doi model

Stress relaxation measurements for large step strains were performed in shear and biaxial extension using an entangled monodisperse polystyrene melt. The shear and biaxial damping functions were obtained, which agreed very well with our previous data for other monodisperse polystyrene melts. The applicability of the Mead, Larson and Doi (MLD) model to the nonlinear damping behavior was investigated based on these experimental data as well as on the previous data of the uniaxial damping function. The experimental data of shear and uniaxial damping functions were larger than the MLD prediction and were closer to the prediction of the Doi–Edwards model with the independent alignment approximation. On the other hand, the experimental biaxial damping function agreed very well with the MLD prediction. The convective constraint release (CCR) accelerates the orientation relaxation when the stretched chain contracts and the CCR gives stronger strain dependence for the damping functions in shear, uniaxial and biaxi...

Evaluation of Surficial Stability for Homogeneous Slopes Considering Rainfall Characteristics

Shallow slope failures in residual soil during periods of prolonged infiltration are commonly occurring in the world. This study examines an infinite slope analysis to estimate the influence of infiltration on surficial stability of slopes by the limit equilibrium method. An approximate method that accommodates the boundary condition of a uniform rainfall has been proposed to evaluate the likelihood of shallow slope failure that is induced by a particular rainfall event. The method based on the Mein and Larson model, which provides an explicit solution for preponding infiltration, has been applied to various types of soil having measured unsaturated hydraulic properties. To compare results with those obtained from the approximate method, a series of numerical analyses were carried out. According to the results, with the use of properly estimated input parameters, the approximate method was found to give results that compare reasonably well with those of more rigorous finite element analyses.

微分型粘弾性構成方程式の非線形レオロジー特性の予測能力

We propose a kinetics model including extension and anisotropic movement between entangled or branched chains and develop constitutive equations containing the Larson model and the Giesekus model through non-linear parameters. In order to make clear the characteristics of the developed constitutive equations, we examined the predictions of using non-linear parameters and a non-linear stress relaxation modulus. We found that the proposed model shows better predictions of the nonlinear stress relaxation after a double-step shear strain than those of the Larson and the Giesekus models. Furthermore, we found that the proposed model is able to predict the biaxial elongational viscosity and the first planar elongational viscosity comparatively well by fitting the uniaxial elongational viscosity curve.However, the predictions of stress relaxation in the time-strain inseparable region was at most qualitative, and the predictions of the second normal stress difference and the second planar elongational viscosity were lower than experimental results because of the assumptions or crude approximations used in our development.

Viscoelastic simulation of film casting process for a polymer melt

AbstractNumerical simulations of the film casting process were performed using a finite element method for Newtonian and viscoelasttc fluids. We simplified the governing equations by the assumption that the stress and velocity gradients in the thickness direction were negligible, and obtained the film thickness and mean value of stress and velocity components in the thickness direction as variables. Viscoelasticity was described by the Larson model with multiple relaxation times. Non‐isothermal conditions were considered by applying the time‐temperature superposition law. The simulation results for the several kinds of commercial low‐density polyethylenes wore compared to the experimental data for a laboratory‐scale process at l90°C and a commercial‐scale process at 310°C. The film width and film thickness distribution at chill roll, and the change of film width were in good agreement for the laboratory‐scale process, but the agreement for the commercial‐scale process was; not as good. In the simulation of the commercial‐scale process at high temperature, the value predicted by the use of the Viscoelasticity for the original pellet showed poor agreement owing to the change of Viscoelasticity in the process. The agreement was improved by the use of the Viscoelasticity for the processed resin, which was changed from the original one. Next, viscoelastic effects on neck‐in and edge bead phenomena were investigated. The neck‐in and edge bead phenomena were considered to be affected by both the uniaxial elongational viscosity and planar elongational viscosity.

Numerical Simulation of Extrudate Swell Problem and Evaluation of Applicability of Viscoelastic Constitutive Models. 1. A Study on Axisymmetric Extrudate Swell from a Straight Die.

Numerical simulations of axisymmetric extrudate swell for a low density polyethyrene (LDPE IUPAC-A) melt were carried out using the K-BKZ model as an integral type and the PTT and Larson models as a differential type. We employed both the reversible and irreversible models for the K-BKZ and Larson models to investigate the effect of reversing deformation on the extrudate swell from a straight die. First, relaxation spectrum and nonlinear parameters in the constitutive equation were determined from dynamic data of linear viscoelasticity and steady shear flow data by using the nonlinear regression, and then they were applied to the simulation of extrudate swell problem. We evaluated the applicability of these models by comparing experiments and simulation for both rheological data and extrudate swell ratio. For the K-BKZ model, the reversible model over-estimates the swell ratio in high shear rate, whereas the irreversible model predicts the experimental data with high accuracy. The irreversible Larson model also shows the good prediction of swell, on the other hand, the reversible one over-estimates the swell and there exists the multiple solutions. For the PTT model, we carried out the simulation using the models with different values of nonlinear parameter, e , which has the same steady shear flow properties and the different properties of stress relaxation under reversing double step deformation. The model having the larger stress in the stress relaxation under reversing double step deformation shows the larger swell. From these results, we find that the consideration of reversing deformation characteristics is required for the extrudate swell from the straight die.