scholarly journals Modelling of elastic properties of sintered porous materials

2013 ◽  
Vol 469 (2154) ◽  
pp. 20120689 ◽  
Author(s):  
A. V. Manoylov ◽  
F. M. Borodich ◽  
H. P. Evans
Keyword(s):  
Experimental Data ◽  
Porous Materials ◽  
Damage Accumulation ◽  
Statistical Distributions ◽  
Metal Powders ◽  
Combined Model ◽  
Loaded Material ◽  
Sintered Materials ◽  
Good Agreement ◽  
Elastic Characteristics

Models for prediction of the elastic characteristics of natural and synthetic porous materials are re-examined and new models are introduced. First, the Vavakin–Salganik (VS) model for materials with isolated spherical pores is extended in order to take into account various statistical distributions of pore sizes. It is shown that the predictions of the extended VS model are in good agreement with experimental data for porous materials with isolated pores such as foamed titanium, porous glass and sandstone. However, the model is in a considerable disagreement with the experimental data for materials sintered from metal powders. The disagreement is explained by the presence of merged and open pores whose shapes cannot be well approximated as spheres. Using the theory of geometrical probabilities, the amount of pores that are close enough to overlap is estimated, and a model is introduced where merging pores are modelled as corresponding ellipsoids. Another modification is proposed to take into account open pores. This modification is based on the classical Rabotnov–Kachanov approach to damage accumulation in the loaded material. Finally, predictions given by the above models, and their combination is compared with experiments. A good agreement is observed between the combined model and the available experimental data for a variety of sintered materials.

scholarly journals Modeling the process of grinding feed by the method of damage accumulation

2021 ◽  
Vol 284 ◽  
pp. 02021
Author(s):  
Timmo Gavrilov
Keyword(s):  
Experimental Data ◽  
Particle Size ◽  
Energy Consumption ◽  
Damage Accumulation ◽  
Optimal Number ◽  
Grinding Process ◽  
Technological Parameters ◽  
Number Of Cycles ◽  
Working Bodies ◽  
Good Agreement

The efficiency of the process of grinding meat and bone feed depends on a number of design and technological parameters of the grinder operation. One of the most significant issues and at the same time the least studied one is the influence of the number of cycles of loading meat and bone feed with the working bodies of grinders on the particle size of the finished meat and bone feed. To study this issue, the authors proposed a method for modeling the process of grinding meat and bone feed using a stochastic B-model of cumulative damage, which is based on an understanding of the process under study at the macroscopic level and experimental data. The constructed B-model made it possible to determine the optimal number of cycles of loading meat and bone feed with the working bodies of the grinders, at which the required particle size of the finished meat and bone feed is 3...5 mm, and there is no unnecessary energy consumption of the grinding process. This number is equal to 12...18 cycles. The results obtained by the B-model are in good agreement with the experimental data. The constructed B-model of the grinding process of meat and bone feed will further help optimizing the operation of the cutting device and reducing energy consumption for the operation of the grinders as a whole.

scholarly journals Numerical modeling of the porosity influence on the elastic properties of sintered materials

2019 ◽  
Vol 51 (2) ◽  
pp. 153-161
Author(s):  
Elmiladi Abdulrazag ◽  
Igor Balac ◽  
Katarina Colic ◽  
Aleksandar Grbovic ◽  
Milorad Milovancevic ◽  
...  
Keyword(s):  
Experimental Data ◽  
Numerical Model ◽  
Elastic Properties ◽  
Volume Fraction ◽  
Unit Cell ◽  
Material Microstructure ◽  
Two Phase ◽  
Material Porosity ◽  
Sintered Materials ◽  
Elastic Characteristics

The effect of structural porosity on the elastic properties of sintered materials was studied using the new multi-pore unit cell numerical model - MPUC. Comparison between proposed MPUC model and previously adopted two-phase unit cell - FCC numerical model as well as available experimental data in literature, was done by comparing obtained values for modulus of elasticity - E, shear modulus - G and Bulk modulus - K. Results obtained by proposed MPUC model are in excellent agreement with available experimental data in literature. It was confirmed that material porosity regarding pores? size (volume fraction) has noticeable influence on elastic properties of sintered material. Less porosity in the material microstructure generally leads to noticeable higher values of E, G and K. For fixed volume fraction, shape of pores has no significant influence on elastic characteristics.

scholarly journals A Study of Cover Materials Which Influence Rn222 Exhalation Indoors

2019 ◽  
Vol 7 ◽  
pp. 177
Author(s):  
C. Raptis ◽  
A. Savidou ◽  
P. Kritidis
Keyword(s):  
Experimental Data ◽  
Porous Materials ◽  
Building Materials ◽  
Radon Exhalation ◽  
Radon Diffusion ◽  
Good Agreement

The wall covers can decrease or increase the radon exhalation; this depends on whether the material acts mostly as a sealer against radon exhalation or as a source of radon. This work is a study of different kind of wall covers which influence radon exhalation from surfaces of building materials. The experimental data are in good agreement with the evaluations according to the theory of radon diffusion through porous materials.

Dynamic Simulation of Ultra-Shallow Implantation Profiles in Single-Crystalline Silicon

1995 ◽  
Vol 389 ◽  
Author(s):  
Matthias Posselt
Keyword(s):  
Experimental Data ◽  
Damage Accumulation ◽  
Crystalline Silicon ◽  
Critical Value ◽  
Binary Collision ◽  
Single Crystalline Silicon ◽  
Depth Profiles ◽  
High Doses ◽  
Different Doses ◽  
Good Agreement

ABSTRACTThe binary collision code Crystal-TRIM is applied to simulate 15 keV BF+2 and As+ implantations into channeling and "random" directions, at different doses. The buildup of radiation damage is described by assuming statistical creation of local amorphous regions and formation of amorphous zones if the density and/or size of the local amorphous regions exceeds a critical value. Damage accumulation during ion bombardment causes enhanced dechanneling and, therefore, the alteration of the shape of range and damage profiles. The depth profiles calculated by Crystal-TRIM show a good agreement with experimental data. The thickness of the amorphous layers formed at high doses is also in accordance with measurements.

Hot isostatic pressing process simulation: application to metal powders

2012 ◽  
Vol 90 (6) ◽  
pp. 573-583 ◽  
Author(s):  
L. Redouani ◽  
S. Boudrahem
Keyword(s):  
Experimental Data ◽  
Process Simulation ◽  
Hot Isostatic Pressing ◽  
Transport Mechanisms ◽  
Metal Powders ◽  
Isostatic Pressing ◽  
Powder Characteristics ◽  
Theoretical Results ◽  
Tungsten Powders ◽  
Good Agreement

Deformation and transport mechanisms of matter, which intervene in the powder densification process by hot isostatic pressing (HIP), are very complicated to put into equation form. Their contribution to densification depends on powder characteristics, their configuration in aggregates, and the used HIP cycle parameters (temperature, pressure, and time). In this work, we have envisaged modifications that seemed to us necessary to bring to the previous simulations, so that their predictions will be related to experiment. New equations were established to evaluate the efficient pressure and the contributions of different mechanisms. The obtained results are used for the construction of densification diagrams by the HIP of copper, nickel, and tungsten powders and to the comparison with the experimental data. The comparative tables, between theoretical results and experimental data, were established for tin and lead. The simulation predictions are in good agreement with experimental results.

Energy Levels and Electromagnetic Transition of 90-94mo Nuclei Using Ibm-1

2020 ◽  
pp. 149-152
Keyword(s):  
Experimental Data ◽  
Transition Probability ◽  
Energy Levels ◽  
Dynamical Symmetry ◽  
Interacting Boson Model ◽  
Excitation Energies ◽  
Electromagnetic Transition ◽  
Boson Model ◽  
Energy States ◽  
Good Agreement

The energy states for the J , b , ɤ bands and electromagnetic transitions B (E2) values for even – even molybdenum 90 – 94 Mo nuclei are calculated in the present work of "the interacting boson model (IBM-1)" . The parameters of the equation of IBM-1 Hamiltonian are determined which yield the best excellent suit the experimental energy states . The positive parity of energy states are obtained by using IBS1. for program for even 90 – 94 Mo isotopes with bosons number 5 , 4 and 5 respectively. The" reduced transition probability B(E2)" of these neuclei are calculated and compared with the experimental data . The ratio of the excitation energies of the 41+ to 21+ states ( R4/2) are also calculated . The calculated and experimental (R4/2) values showed that the 90 – 94 Mo nuclei have the vibrational dynamical symmetry U(5). Good agreement was found from comparison between the calculated energy states and electric quadruple probabilities B(E2) transition of the 90–94Mo isotopes with the experimental data .

Predicting the Effect of Tire Tread Pattern Design on Thick Film Wet Traction

1977 ◽  
Vol 5 (1) ◽  
pp. 6-28 ◽  
Author(s):  
A. L. Browne
Keyword(s):  
Experimental Data ◽  
Network Design ◽  
Thick Film ◽  
Digital Computer ◽  
Analytical Tool ◽  
Design Practice ◽  
Pattern Design ◽  
Performance Results ◽  
Good Agreement

Abstract An analytical tool is presented for the prediction of the effects of changes in tread pattern design on thick film wet traction performance. Results are reported for studies in which the analysis, implemented on a digital computer, was used to determine the effect of different tread geometry features, among these being the number, width, and lateral spacing of longitudinal grooves and the angle of zigzags in longitudinal grooves, on thick film wet traction. These results are shown to be in good agreement with experimental data appearing in the literature and are used to formulate guidelines for tread groove network design practice.

A New Condition of Formation and Stablity of All Crystalline Systems in a Good Agreement with Experimental Data

2015 ◽  
Vol 11 (3) ◽  
pp. 3224-3228
Author(s):  
Tarek El-Ashram
Keyword(s):  
Experimental Data ◽  
Brillouin Zone ◽  
Electron Concentration ◽  
Free Electron ◽  
Lattice Point ◽  
Valence Electron ◽  
Fermi Gas ◽  
Valence Electron Concentration ◽  
Fermi Sphere ◽  
Good Agreement

In this paper we derived a new condition of formation and stability of all crystalline systems and we checked its validity andit is found to be in a good agreement with experimental data. This condition is derived directly from the quantum conditionson the free electron Fermi gas inside the crystal. The new condition relates both the volume of Fermi sphere VF andvolume of Brillouin zone VB by the valence electron concentration VEC as ;𝑽𝑭𝑽𝑩= 𝒏𝑽𝑬𝑪𝟐for all crystalline systems (wheren is the number of atoms per lattice point).

Virus Removal by Filtration

1982 ◽  
Vol 14 (4-5) ◽  
pp. 253-256
Author(s):  
N Sriramula ◽  
M Chaudhuri
Keyword(s):  
Experimental Data ◽  
Escherichia Coli ◽  
Cationic Polyelectrolyte ◽  
Electrokinetic Phenomena ◽  
Virus Removal ◽  
Bacterial Virus ◽  
Gravity Settling ◽  
And Diffusion ◽  
Model Virus ◽  
Good Agreement

An investigation was undertaken on the removal of a model virus, bacterial virus MS2 against Escherichia coli, by sand filtration using untreated, and alum or cationic polyelectrolyte treated media, and uncoagulated as well as alum coagulated influent. Data on discrete virus removal were satisfactorily accounted for by electrokinetic phenomena and diffusion. For virus in association with turbidity, filter coefficients computed from experimental data were in good agreement with those predicted by mechanical straining and gravity settling which were the dominant mechanisms for removal of the turbidity particles to which the viruses attached.

Diffusion model for deposition of epitaxial GaAs layers prepared by the MOCVD method

1991 ◽  
Vol 56 (10) ◽  
pp. 2020-2029
Author(s):  
Jindřich Leitner ◽  
Petr Voňka ◽  
Josef Stejskal ◽  
Přemysl Klíma ◽  
Rudolf Hladina
Keyword(s):  
Experimental Data ◽  
Growth Rate ◽  
Kinetic Model ◽  
Gas Phase ◽  
Substrate Surface ◽  
Deposition Process ◽  
Hydrogen Atmosphere ◽  
Epitaxial Gaas ◽  
Kinetics Of ◽  
Good Agreement

The authors proposed and treated quantitatively a kinetic model for deposition of epitaxial GaAs layers prepared by reaction of trimethylgallium with arsine in hydrogen atmosphere. The transport of gallium to the surface of the substrate is considered as the controlling process. The influence of the rate of chemical reactions in the gas phase and on the substrate surface on the kinetics of the deposition process is neglected. The calculated dependence of the growth rate of the layers on the conditions of the deposition is in a good agreement with experimental data in the temperature range from 600 to 800°C.

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