Temperature dependence of dielectric properties of moist soils

2008 ◽  
Vol 45 (6) ◽  
pp. 888-894 ◽  
Author(s):  
Arun P. Jaganathan ◽  
Erez N. Allouche
Keyword(s):  
Experimental Data ◽  
Dielectric Properties ◽  
Land Mines ◽  
Temperature Dependency ◽  
Moisture Contents ◽  
Moist Sand ◽  
Proposed Model ◽  
Dielectric Model ◽  
Semi Empirical ◽  
Good Agreement

Heating of soil using microwaves has several applications in geosciences, including soil remediation, neutralization of land mines, and microwave-enhanced thermography. Numerical simulation of microwave-induced soil heating processes requires knowledge of the electrical properties of the soil as a function of temperature, moisture content, and frequency of the electromagnetic wave. This paper describes a semi-empirical model for calculating the dielectric properties of moist soils at various moisture contents, temperatures, and frequencies (within the band of 1–10 GHz). The proposed model is an extension of the generalized refractive mixing dielectric model (GRMDM) for moist soils. Predictions of the proposed model were found to be in good agreement with experimental data reported in the literature. Results of a parametric study suggest that the temperature dependency of the dielectric properties of moist sand is more pronounced for higher volumetric moisture contents.

scholarly journals Modelling the Characteristics of Ring-Shaped Magnetoelastic Force Sensor in Mohri’s Configuration

Sensors ◽  
2020 ◽  
Vol 20 (1) ◽  
pp. 266 ◽  
Author(s):  
Anna Ostaszewska-Liżewska ◽  
Roman Szewczyk ◽  
Peter Raback ◽  
Mika Malinen
Keyword(s):  
Experimental Data ◽  
High Sensitivity ◽  
Force Sensor ◽  
Inhomogeneous Distribution ◽  
The Finite Element Method ◽  
The Core ◽  
Magnetoelastic Effect ◽  
Proposed Model ◽  
Distribution Of Stresses ◽  
Good Agreement

Magnetoelastic force sensors exhibit high sensitivity and robustness. One commonly used configuration of force sensor with a ring-shaped core was presented by Mohri at al. In this configuration force is applied in the direction of a diameter of the core. However, due to inhomogeneous distribution of stresses, model of such sensor has not been presented yet. This paper is filling the gap presenting a new method of modelling the magnetoelastic effect, which is especially suitable for the finite element method. The presented implementation of proposed model is in good agreement with experimental data and creates new possibilities of modelling other devices utilizing magnetoelastic effect.

The Prediction of Thermal Conductivity of Agricultural Residues from Straw for Biomass Energy

2013 ◽  
Vol 779-780 ◽  
pp. 1419-1422 ◽  
Author(s):  
Lin Lu ◽  
Li Jiang ◽  
Qing Feng ◽  
He Ping Wang
Keyword(s):  
Thermal Conductivity ◽  
Rice Straw ◽  
Agricultural Residues ◽  
Biomass Energy ◽  
Thermal Probe ◽  
Moisture Contents ◽  
Proposed Model ◽  
Wire Method ◽  
The Relationship ◽  
Good Agreement

Agricultural residues from straw are widely used for energy and other applications. The thermal conductivity is one of the most important thermophysical properties considered when using agricultural residues, such as rice straw, in renewable energy engineering. In this paper, the thermal conductivity of rice straw was measured using a thermal probe by the transient hot wire method at selected moisture contents, temperatures and dry densities. The moisture contents of the samples ranged from 0 to 21.47 percent wet basis and the dry densities ranged from 90.7 to 136.4 kg/m3 and the temperature ranged from 0 to 170°C. Under those conditions, the thermal conductivity was measured and analyzed. Experiment results showed that the thermal conductivity increases with the increases of the density, moisture content and temperature, and the relationship among them is approximately described in a linear way. A new model to predict the thermal conductivity of agricultural residues from straw was proposed. The calculated results by the proposed model are in good agreement with the experimental data.

Analysis and Validation of Cutting Forces Prediction Models in Micromachining

2006 ◽  
Vol 526 ◽  
pp. 13-18 ◽  
Author(s):  
H. Perez ◽  
Antonio Vizan Idoipe ◽  
J. Perez ◽  
J. Labarga
Keyword(s):  
Experimental Data ◽  
Cutting Force ◽  
Cutting Forces ◽  
Prediction Models ◽  
Precision Machining ◽  
New Model ◽  
Proposed Model ◽  
On Line ◽  
Machine Control ◽  
Good Agreement

Many investigations have been developed related to precision machining with features in the millimetre scale. In this paper different cutting force models for micromilling are analyzed and compared. A new model based on specific cutting force that also considers run-out errors has been developed. The estimated cutting forces obtained with this model had good agreement with the experimental data. Also, the proposed model allows to be implemented within the machine control for the on-line optimization of the micromilling process.

Fluid Forces Induced by Vortex Shedding

1976 ◽  
Vol 98 (1) ◽  
pp. 19-24 ◽  
Author(s):  
R. D. Blevins ◽  
T. E. Burton
Keyword(s):  
Experimental Data ◽  
Vortex Shedding ◽  
Model Parameters ◽  
Amplitude Dependence ◽  
Fluid Forces ◽  
At Resonance ◽  
Elastic Cylinders ◽  
Random Vibration Theory ◽  
Semi Empirical ◽  
Good Agreement

A semi-empirical, dynamic model for investigating the fluid forces induced on a bluff cylinder by vortex shedding is developed using random vibration theory. The model includes both spanwise correlation effects and the amplitude dependence of the correlated vortex forces. Model parameters are determined by experimental data. The results are then applied to determine the forces exerted on elastic cylinders at resonance with vortex shedding. The predictions are in good agreement with experimental data.

Novel Model for the Optical Function: Application to Hexagonal Gan

2001 ◽  
Vol 677 ◽  
Author(s):  
Y. Chan ◽  
Aleksandra B. Djurišić ◽  
E. Herbert Li
Keyword(s):  
Experimental Data ◽  
Closed Form ◽  
Dielectric Function ◽  
Absorption Edge ◽  
Low Energy ◽  
Optical Function ◽  
Complex Dielectric Function ◽  
Proposed Model ◽  
Novel Model ◽  
Good Agreement

ABSTRACTIn this work we propose an analytical expression for the complex dielectric function that includes both discrete and continuum exciton effects. The model is based on the work of Elliott and the proposed model has been applied to modeling the experimental data for the hexagonal GaN. We have obtained good agreement with the experimental data. The model assumes Lorentzian broadening in order to obtain dielectric function equations in analytically closed form. We show that Lorentzian broadened dielectric function decays more slowly than the experimental data for hexagonal GaN at the low energy side. This indicates that the broadening of the absorption edge in GaN is not purely Lorentzian. The agreement with the experimental data can be improved using adjustable broadening modification.

scholarly journals Thermodynamic modelling of the binary indium-lithium system, a promising li-ion battery material

2021 ◽  
pp. 41-41
Author(s):  
Wojciech Gierlotka ◽  
Władysław Gąsior ◽  
Adam Dębski ◽  
Miłosz Zabrocki
Keyword(s):  
Experimental Data ◽  
Ternary Systems ◽  
Calphad Approach ◽  
Li Ion Battery ◽  
System A ◽  
Proposed Model ◽  
Component Systems ◽  
Li Ion ◽  
Battery Material ◽  
Good Agreement

The binary In - Li system is a promising Li-ion battery anode material as well as a part of the important ternary Ge - In - Li system. The thermodynamic descriptions of metallic systems are widely used to retrieve information necessary for alloy applications. In this work, a thermodynamic model of a binary indium - lithium system prepared by the Calphad approach is proposed. The liquid phase was described by an associate model, and the solid phases determined by the ab-initio calculation were included in thermodynamic modeling. The obtained set of self-consistent thermodynamic parameters well reproduces the available experimental data and enables further calculations of multi-component systems. A good agreement between the calculations and the available experimental data was found. The proposed model can be used for further descriptions of ternary systems.

Empirical estimation of engine-integration noise for high bypass ra-tio turbofan engines

2021 ◽  
Vol 263 (2) ◽  
pp. 4511-4519
Author(s):  
Incheol Lee ◽  
Yingzhe Zhang ◽  
Dakai Lin
Keyword(s):  
Experimental Data ◽  
Pressure Side ◽  
Empirical Estimation ◽  
Low Frequencies ◽  
High Frequencies ◽  
Turbofan Engines ◽  
Proposed Model ◽  
The Impact ◽  
Bypass Ratio ◽  
Good Agreement

To investigate the impact of installation on jet noise from modern high-bypass-ratio turbofan engines, a model-scale noise experiment with a jet propulsion system and a fuselage model in scale was conducted in the anechoic wind tunnel of ONERA, CEPRA 19. Two area ratios (an area of the secondary nozzle over an area of the primary nozzle), 5 and 7, and various airframe configurations such as wing positions relative to the tip of the engine nacelle and flap angles, were considered. Based on the analysis of experimental data, an empirical model for the prediction of engine installation noise was proposed. The model comprises two components: one is the interaction be-tween the jet and the pressure side of the wing, and the other is the interaction between the jet and the flap tip. The interaction between the jet and the pressure side of the wing contributes to the noise at the low frequencies (≤ 1.5 kHz), and the interaction between the jet and the flap tip con-tributes to the noise at the high frequencies. The proposed model showed a good agreement with the experimental data.

VLE Determination of Carbon Dioxide Loaded Aqueous Alkanolamine Mixtures Using Modified Kent Eisenberg Model

2017 ◽  
Vol 231 (11-12) ◽  
Author(s):  
Humbul Suleman ◽  
Abdulhalim Shah Maulud ◽  
Zakaria Man
Keyword(s):  
Experimental Data ◽  
Carbon Dioxide ◽  
Model Parameters ◽  
Thermodynamic Models ◽  
Carbon Dioxide Absorption ◽  
Proposed Model ◽  
Wide Range ◽  
Experimental Values ◽  
Good Agreement

AbstractA computationally simple thermodynamic framework has been presented to correlate the vapour-liquid equilibria of carbon dioxide absorption in five representative types of alkanolamine mixtures. The proposed model is an extension of modified Kent Eisenberg model for the carbon dioxide loaded aqueous alkanolamine mixtures. The model parameters are regressed on a large experimental data pool of carbon dioxide solubility in aqueous alkanolamine mixtures. The model is applicable to a wide range of temperature (298–393 K), pressure (0.1–6000 kPa) and alkanolamine concentration (0.3–5 M). The correlated results are compared to the experimental values and found to be in good agreement with the average deviations ranging between 6% and 20%. The model results are comparable to other thermodynamic models.

Kinetic Model of Thermoelastic Martensite Transformation in Niti and NiMn Based Shape Memory Alloys

1995 ◽  
Vol 398 ◽  
Author(s):  
K. H. Wu ◽  
J.D. Shi ◽  
F. Yang ◽  
Z. J. Pu
Keyword(s):  
Experimental Data ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Martensite Transformation ◽  
Quantitative Model ◽  
Proposed Model ◽  
Series Of Experiments ◽  
The Relationship ◽  
Kinetics Of ◽  
Good Agreement

ABSTRACTA new, quantitative model was developed to describe the martensite transformation kinetics of thermoelastic shape memory alloys (SMAs). In addition, a series of experiments were conducted to study the Kinetics of thermoelastic martensite transformation in four SMA systems: NiTi, NiTi-15at%Hf, NiTi-20at%Zr and NiMn-7.5at%Ti alloys. Comparisons between data of the kinetic of martensite transformation with the present theoretic models show that the proposed model is in good agreement and concurs with the experimental data. Also, a comparison of data from the proposed model with data from existing kinetic models, such as Liang's and Magee's [1,7], indicates that the proposed model can better describe the experimental data, including the relationship between dξ(T)/dT and ξ, and dξ(T)/dT and T.

scholarly journals Modelling of Transient Slug Flow in Pipeline

1997 ◽  
Author(s):  
T. N. Wong ◽  
Y. K. Yau
Keyword(s):  
Experimental Data ◽  
Theoretical Prediction ◽  
Slug Flow ◽  
Valve Closure ◽  
Liquid Slug ◽  
Proposed Model ◽  
Pressure Surge ◽  
Slug Flows ◽  
Gas Expansion ◽  
Good Agreement

An approach to model slug flow in horizontal pipeline is presented which is based on a transient Lagrangian formulation. The effect of slug growth is modelled by considering the gas expansion, picking up of liquid film ahead of the slug and shading of liquid from the slug tail. This method is particular useful for slug flows approaching the end of a pipeline. The validation of the theoretical prediction is confirmed by comparing with the experimental measurement. The proposed model is further used to analyse shock phenomenon caused by a rapid valve closure in a gas-liquid slug flows system. The results show that the pressure surge is highly dependent on the local void fraction at the valve during closure. Good agreement has been obtained between prediction and experimental data by Akagawa et al (1982).

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