scholarly journals A continuum mechanical framework for modeling tumor growth and treatment in two- and three-phase systems

2021 ◽  
Author(s):  
Cass T. Miller ◽  
William G. Gray ◽  
Bernhard A. Schrefler
Keyword(s):  
Tumor Growth ◽  
Entropy Inequality ◽  
Phase Model ◽  
Treatment Modalities ◽  
Two Phase ◽  
Length Scales ◽  
Potential Models ◽  
Three Phase ◽  
Wide Range ◽  
Closure Relations

AbstractThe growth and treatment of tumors is an important problem to society that involves the manifestation of cellular phenomena at length scales on the order of centimeters. Continuum mechanical approaches are being increasingly used to model tumors at the largest length scales of concern. The issue of how to best connect such descriptions to smaller-scale descriptions remains open. We formulate a framework to derive macroscale models of tumor behavior using the thermodynamically constrained averaging theory (TCAT), which provides a firm connection with the microscale and constraints on permissible forms of closure relations. We build on developments in the porous medium mechanics literature to formulate fundamental entropy inequality expressions for a general class of three-phase, compositional models at the macroscale. We use the general framework derived to formulate two classes of models, a two-phase model and a three-phase model. The general TCAT framework derived forms the basis for a wide range of potential models of varying sophistication, which can be derived, approximated, and applied to understand not only tumor growth but also the effectiveness of various treatment modalities.

Transport of organochlorine pesticides in soil columns enhanced by dissolved organic carbon

1997 ◽  
Vol 35 (7) ◽  
pp. 139-145 ◽  
Author(s):  
Jiann-Yuan Ding ◽  
Shian-Chee Wu
Keyword(s):  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Organochlorine Pesticides ◽  
Transport Model ◽  
Phase Model ◽  
Soil Columns ◽  
Two Phase ◽  
Three Phase ◽  
Phase Transport ◽  
Remediation Of Soil

The objective of this study is to quantify the effects of humic acid solution infiltration on the transport of organochlorine pesticides (OCPs) in soil columns using a three-phase transport model. From experimental results, it is found that the dissolved organic carbon enhances the transport of OCPs in the soil columns. In the OCPs-only column, the concentration profiles of OCPs can be simulated well using a two-phase transport model with numerical method or analytical solution. In the OCPs-DOC column, the migrations of aldrin, DDT and its daughter compounds are faster than those in the OCPs-only column. The simulation with the three-phase model is more accurate than that with the two-phase model. In addition, significant decrease of the fluid pore velocities of the OCPs-DOC column was found. When DOC leachate is applied for remediation of soil or groundwater pollution, the decrease of mean pore velocities will be a crucial affecting factor.

Activity coefficients, densities, dipole moments, and surface tensions of the system triethylamine–methylethylketone–water

1981 ◽  
Vol 59 (1) ◽  
pp. 127-131 ◽  
Author(s):  
Alan N. Campbell
Keyword(s):  
Surface Layer ◽  
Dipole Moments ◽  
Phase System ◽  
Constant Composition ◽  
Two Phase ◽  
Three Phase ◽  
Wide Range ◽  
Isothermal System ◽  
Total Composition ◽  
Two Phases

The properties named in the title have been determined by standard methods. Viscosity, molar volume, and orientation polarisation all indicate abnormalities of the nature of association between the components.The most interesting result is that of surface tension which indicates that, in the case of the binary system triethylamine–water, a surface layer of constant composition is formed over a wide range of total composition. When, by a rise in temperature of two or three degrees, this layer becomes unstable, it splits into two phases of different composition. The surface layer may then be instantaneously reformed and so on. A mechanism for the generation of a two-phase system is thus established. The data for the three-phase, isothermal, system are not so convincing, for reasons that are suggested.

An Edge Dislocation in a Three-Phase Composite Cylinder Model

1991 ◽  
Vol 58 (1) ◽  
pp. 75-86 ◽  
Author(s):  
H. A. Luo ◽  
Y. Chen
Keyword(s):  
Edge Dislocation ◽  
Stable Equilibrium ◽  
Phase Model ◽  
Composite Cylinder ◽  
Two Phase ◽  
Trapping Mechanism ◽  
Three Phase ◽  
Cylinder Model ◽  
Stable Equilibrium Position ◽  
The Stability

An exact solution is given for the stress field due to an edge dislocation embedded in a three-phase composite cylinder. The force on the dislocation is then derived, from which a set of simple approximate formulae is also suggested. It is shown that, in comparison with the two-phase model adopted by Dundurs and Mura (1964), the three-phase model allows the dislocation to have a stable equilibrium position under much less stringent combinations of the material constants. As a result, the so-called trapping mechanism of dislocations is more likely to take place in the three-phase model. Also, the analysis and calculation show that in the three-phase model the orientation of Burgers vector has only limited influence on the stability of dislocation. This behavior is pronouncedly different from that predicted by the two-phase model.

scholarly journals Development of LDPE Crystallinity in LDPE/Cu Composites

2021 ◽  
Author(s):  
Makki Abdelmouleh ◽  
Ilyes Jedidi
Keyword(s):  
Phase Change Materials ◽  
Research Work ◽  
Orthorhombic Phase ◽  
Copper Particle ◽  
Phase Model ◽  
Spectral Simulation ◽  
Two Phase ◽  
Cu Films ◽  
Three Phase

This chapter summarizes the study of the filler (ie copper) effect on LDPE phasic composition in LDPE/Cu composites prepared in solution. During this research work, a particular effort is focused on the use of DSC under non-standard conditions. Therewith, the presence of copper microparticles has a great effect on the network phase than on the crystalline long-range-order phase of LDPE structure. Furthermore, LDPE phasic composition in absence and presence of copper microparticles is investigated by FTIR spectroscopy followed by a spectral simulation of the band that appeared at 720 cm−1 corresponding to the CH2. Anywise, the two-phase model confirmed that no variation is observed of LDPE phase composition for all copper contents into LDPE/Cu films. However, with the three-phase model the orthorhombic phase fraction was found to be constant compared to the fraction of amorphous and that of network phase were found to increase and decrease respectively with increase in the copper particle load in the film. Overall, the thermal and structural behavior of LDPE in presence of copper particles allows this type to be used as phase change materials (PCMs) by adding a paraffin fraction in the LDPE/Cu composite. An update of the most relevant work carried out in the field of phasic characterization of polyethylene is presented in this chapter.

Prediction of Minimum Fluidization Velocity in Two-Phase and Three-Phase Fluidized Beds: Air/Newtonian and Non-Newtonian Liquids

2010 ◽  
Vol 8 (1) ◽  
Author(s):  
Sivakumar Venkatachalam ◽  
Senthilkumar Kandasamy
Keyword(s):  
Fluidized Beds ◽  
Velocity Correlation ◽  
Two Phase ◽  
Minimum Fluidization Velocity ◽  
Fluidization Velocity ◽  
Minimum Fluidization ◽  
Three Phase ◽  
Wide Range ◽  
Data Points ◽  
Newtonian Liquids

The present experimental data on minimum fluidization velocity for two-phase and three-phase fluidized beds, involving 459 measurements were used for the analysis. Apart from this, 70 literature data points from different published sources, using 11 different liquids and 11 different particles have been used for the development of minimum fluidization velocity correlation. The developed correlation for the prediction of the minimum fluidization velocity for two-phase and three-phase fluidized beds was found to be satisfactory for the Newtonian and non-Newtonian systems with a wide range of variables covered in the present investigation.

scholarly journals The three-phase astrochemical code: modeling of the molecular cloud composition

2021 ◽  
Author(s):  
E. V. Borshcheva ◽  
Keyword(s):  
Observational Data ◽  
Molecular Cloud ◽  
Phase Model ◽  
Chemical Compositions ◽  
Two Phase ◽  
Ice Surface ◽  
Three Phase ◽  
Phase Models ◽  
Dust Surface ◽  
Good Agreement

We describe the implementation of a three-phase astrochemical model (gas + ice surface + bulk) based on the two-phase Presta code (gas + dust surface) and provide results for calculating the molecular cloud composition. The two- and three-phase models produce significantly different chemical compositions. In particular, CO ice abundance in the three-phase model shows good agreement with the observational data, unlike the two-phase model.

scholarly journals Local elastic moduli of simple random composites computed at different length scales

2020 ◽  
Vol 53 (6) ◽  
Author(s):  
E. J. Garboczi ◽  
P. Lura
Keyword(s):  
Young’S Modulus ◽  
Elastic Moduli ◽  
Young's Modulus ◽  
Delta Function ◽  
Two Phase ◽  
Length Scales ◽  
Average Value ◽  
Young’S Moduli ◽  
Three Phase ◽  
Overlapping Spheres

AbstractTechniques like nanoindentation and atomic force microscopy can estimate the local elastic moduli in a region surrounding the probe used. For composites with phase regions much larger than the size of the probe, these procedures can identify the phases via their different elastic moduli but identifying phase regions that are on the same size scale as the indent is more problematic. This paper looks at three random 3D 8003 voxel composite models, each consisting of a matrix and spherical inclusions. One model has non-overlapping spheres and two models have overlapping spheres, with two and three distinct phases. The linear elastic problem is solved for each microstructure, and histograms are made of the local Young’s moduli over a number of sub-volumes (SVs), averaged over progressively larger SVs. The number and shape of histogram peaks change from N delta functions, where N is the number of elastically distinct phases, at the 1 voxel SV limit, to a single delta function located at the value of the effective global Young’s modulus, when the SV equals the unit cell volume. The phase volume fractions are also tracked for each bin in the Young’s modulus histograms, showing the phase make-up of bin in the histogram. There are clear differences seen between the non-overlapping and three-phase overlapping models and the two-phase overlapping sphere model, because of different size microstructural features, characterized by the average value of size as computed by the W(q) function. In the three-phase model, a peak that is originally all phase 3 persists at its same location, but as the size of the SVs increase, it is made up of a mixture of phases, so that it cannot be identified with a single phase even though it remains a clear peak. These results give some guidance as to what probe size might be useful in distinguishing different phases by local elastic moduli measurements, and how the length scales of the probe and the microstructure interact.

Mean normalized shower multiplicity in inelastic hadron–nucleus interactions at high energies and multiparticle production mechanisms

1984 ◽  
Vol 62 (7) ◽  
pp. 639-641
Author(s):  
Dipak Ghosh ◽  
Java Roy ◽  
Madhumita Basu ◽  
Kaushik Sengupta ◽  
Sadhan Naha ◽  
...  
Keyword(s):  
Experimental Data ◽  
Detailed Comparison ◽  
Phase Model ◽  
Multiparticle Production ◽  
Recent Experimental Data ◽  
Dominance Model ◽  
Two Phase ◽  
High Energies ◽  
Wide Range ◽  
Production Mechanisms

This paper presents a detailed comparison of the recent experimental data on mean normalized shower multiplicity in proton–emulsion interactions (22.6–400 GeV/c) with the predictions of current theories of multiparticle production in hadron–nucleus interactions. It has been observed that the data favour both the Fishbane–Trefil two-phase model (TEM) and the Fan diagram dominance model (FDDM) over a wide range of target nuclei, although the agreement with the FDDM seems to be better.

Investigation on Liquid Segregation during Rheo-Casting Process Based on Eulerian-Granular Multiphase Model

2016 ◽  
Vol 256 ◽  
pp. 113-118
Author(s):  
Jiao Jiao Wang ◽  
Qiang Zhu ◽  
Fan Zhang ◽  
Da Quan Li ◽  
You Feng He
Keyword(s):  
Casting Process ◽  
Phase Model ◽  
Multiphase Model ◽  
Forming Process ◽  
Two Phase ◽  
Finite Element Software ◽  
Liquid Phases ◽  
Three Phase ◽  
Liquid Segregation ◽  
Semi Solid

A crucial problem concerned with the semi-solid forming process is the liquid segregation phenomena during shape formation, especially for rheo-casting process. Liquid segregation occurs due to the separation phenomena of the solid grain and the liquid phase. In this work, using commercial finite element software, the liquid segregation during rheo-casting process was numerically investigated by Eulerian-granular multiphase model based on the comparable results of single phase model, Eulerian-granular two-phase and three-phase model, along with Eulerian-granular DDPM three-phase model. In the study, solid grains and liquid phases were regarded as rigid material and non-Newtonian fluid at microscale, separately. This validation was experimentally proved and also compared to the proposed relationship of power law, Herschel-Bulkley model with yield stress at macroscale.

scholarly journals Infrared spectroscopy in the assessment of the mineral composition of kidney stones

2019 ◽  
Vol 85 (4) ◽  
pp. 4-9
Author(s):  
S.M. Kolupayev ◽  
V.N. Lesovoy ◽  
E.P. Bereznyak
Keyword(s):  
Infrared Spectroscopy ◽  
Kidney Stones ◽  
Chemical Compounds ◽  
Calcium Oxalate Monohydrate ◽  
Correct Choice ◽  
Two Phase ◽  
Three Phase ◽  
Surgical Methods ◽  
Wide Range ◽  
Individual Program

As a result of infrared spectroscopy of kidney stones obtained from 59 patients with urolithiasis, a wide range of chemical compounds were identified in the samples, in which whevellite (calcium oxalate monohydrate), hydroxylapatite and uric acid were presented in the largest quantities. Monophasic stones were found in 8.4 % of patients. The two-phase, three-phase and four-phase composition of the samples was determined in 37.2 %, 42.3 % and 11.8 % of patients respectively. Carrying out infrared spectroscopy of kidney stones obtained as a result of self-passage or due to the use of surgical methods will contribute to the correct choice of an individual program for metaphylaxis of urolithiasis in different patients.

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