scholarly journals Foam Formation by Compression/Decompression Cycle of Soft Porous Media

2020 ◽  
Vol 4 (3) ◽  
pp. 31
Author(s):  
Phillip Johnson ◽  
Mauro Vaccaro ◽  
Victor Starov ◽  
Anna Trybala
Keyword(s):  
Mechanical Properties ◽  
Porous Media ◽  
Porous Material ◽  
Foam Formation ◽  
Compression Device ◽  
The Media ◽  
Minimum Separation ◽  
Soft Porous Media ◽  
Predicted Values ◽  
Good Agreement

A theory of the amount of foam produced by compression/decompression cycles of a soft porous media is developed. The amount of foam produced was found to be dependent on both the amount of surfactant within the media and the minimum separation between the plates of the compression device. The latter is determined by the mechanical properties of the soft media. The theory also shows the importance of the decompression of the media as this is the mechanism of where the air penetrates into the soft porous material. The accumulated air is used during the compression stage for foam formation. The theoretically predicted values of foam mass are found to have good agreement with experimental observations, which validates the theory predictions. The theory also predicts independence of the foam produced in terms of the frequency of compression/decompression cycles, which agrees with our experimental observations.

scholarly journals Foam Formation and Interaction with Porous Media

Coatings ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 143 ◽  
Author(s):  
Phillip Johnson ◽  
Mauro Vaccaro ◽  
Victor Starov ◽  
Anna Trybala
Keyword(s):  
Porous Media ◽  
Critical Micelle Concentration ◽  
Sodium Dodecyl ◽  
Surfactant Solution ◽  
Foam Formation ◽  
Compression Device ◽  
Time Interaction ◽  
The Media ◽  
Soft Porous Media ◽  
First Time

Foams are a common occurrence in many industries and many of these applications require the foam to interact with porous materials. For the first time interaction of foams with porous media has been investigated both experimentally and theoretically by O. Arjmandi-Tash et al. It was found that there are three different regimes of the drainage process for foams in contact with porous media: rapid, intermediate and slow imbibition. Foam formation using soft porous media has only been investigated recently, the foam was made using a compression device with soft porous media containing surfactant solution. During the investigation, it was found that the maximum amount of foam is produced when the concentration of the foaming agent (dishwashing surfactant) is in the range of 60–80% m/m. The amount of foam produced was independent of the pore size of the media in the investigated range of pore sizes. This study is expanded using sodium dodecyl sulphate (SDS), which has the same critical micelle concentration as the commercial dishwashing surfactant, where the foam is formed using the same porous media and compression device. During the investigation, it was found that 10 times the critical micelle concentration (CMC) is the optimum concentration for a pure SDS surfactant solution to create foam. Any further increase in concentration after that point resulted in no further mass of foam being generated.

Mathematical Model for Axial Crushing of Hybrid Square Tubes

2011 ◽  
Vol 471-472 ◽  
pp. 664-669 ◽  
Author(s):  
H. Akbarshahi ◽  
Mojtaba Sadighi ◽  
Morteza Shakeri ◽  
M. Mirzaei
Keyword(s):  
Mechanical Properties ◽  
Mathematical Model ◽  
Wave Length ◽  
Axial Loading ◽  
Metal Composite ◽  
Metal Tube ◽  
Collapse Mode ◽  
Predicted Values ◽  
Geometrical Dimensions ◽  
Good Agreement

In this paper, to investigate energy absorption capability of hybrid (metal-composite) square tubes under axial loading, a new theory is proposed based on collapse mode of metal square tubes and considering off-axis strength of each layer of composite. An expression is derived for mean crushing load and folding wave length in terms of mechanical properties and geometrical dimensions of metal tube and composite prepregs wrapped around it. To validate the theoretical model, predicted values for mean crushing load are compared with experimental and numerical results that show reasonably good agreement.

Springback Behavior of an Invar Sheet and Its Perforated Form

2006 ◽  
Vol 505-507 ◽  
pp. 781-786
Author(s):  
Yi Che Lee ◽  
Fuh Kuo Chen
Keyword(s):  
Experimental Data ◽  
Mechanical Properties ◽  
Room Temperature ◽  
Elevated Temperatures ◽  
Tensile Tests ◽  
Test Results ◽  
Bending Tests ◽  
Predicted Values ◽  
Springback Behavior ◽  
Good Agreement

The springback behavior of an invar sheet and its perforated form were examined in the present study. The mechanical properties for invar sheet and perforated invar-sheet at elevated temperatures were first obtained from tensile tests. The test results suggest that both invar sheet and perforated invar-sheet have favorable formability at temperature higher than 200oC. An analytical model was also established to predict the springback of the invar sheet and its perforated form under bending conditions at various elevated temperatures. In order to verify the predicted results, the V-bending tests were conducted for the invar sheet at various temperatures ranging from room temperature to 300. The experimental data indicate that the springback decreases with the rise in temperature for both invar sheet and perforated invar-sheet. The good agreement between the experimental data and the predicted values confirms the validity of the proposed theoretical model as well.

scholarly journals Modelling the change in structure and mechanical properties in dry-snow densification to ice

1998 ◽  
Vol 26 ◽  
pp. 45-50 ◽  
Author(s):  
Vladimir N. Golubev ◽  
Anatoly D. Frolov
Keyword(s):  
Mechanical Properties ◽  
Porous Media ◽  
Physical Properties ◽  
Coordination Number ◽  
Structural Changes ◽  
Structural Parameters ◽  
Experimental Studies ◽  
Density Increase ◽  
Regular Packing ◽  
Good Agreement

The regular packing of spheres or polyhedrons of various shapes linked by rigid bonds is presented and discussed as a model of snow structure. Basic structural parameters of this model are: the coordination number and introduced dimensionless factors of friability and rigidity. The snow densification is described as successive changes of these parameters. Use of the model allows us to relate the density increase from ~130 to ~320, ~550, ~700, ~820 and 917 kg m−3, while the coordination number of the structure increases accordingly from 3 (friable hexagonal) to 4 (tetrahedral), 6 (cubic), 8, 10, 12 (dense hexagonal). These structural changes are in good agreement with the critical densities established in experimental studies of snow densification and the physical properties of snow. It is shown that the model presented allows us to estimate the mechanical properties of ice-porous media: Young’s modulus, Poisson’s ratio and strength.

scholarly journals Modelling the change in structure and mechanical properties in dry-snow densification to ice

1998 ◽  
Vol 26 ◽  
pp. 45-50 ◽  
Author(s):  
Vladimir N. Golubev ◽  
Anatoly D. Frolov
Keyword(s):  
Mechanical Properties ◽  
Porous Media ◽  
Physical Properties ◽  
Coordination Number ◽  
Structural Changes ◽  
Structural Parameters ◽  
Experimental Studies ◽  
Density Increase ◽  
Regular Packing ◽  
Good Agreement

The regular packing of spheres or polyhedrons of various shapes linked by rigid bonds is presented and discussed as a model of snow structure. Basic structural parameters of this model are: the coordination number and introduced dimensionless factors of friability and rigidity. The snow densification is described as successive changes of these parameters. Use of the model allows us to relate the density increase from ~130 to ~320, ~550, ~700, ~820 and 917 kg m−3, while the coordination number of the structure increases accordingly from 3 (friable hexagonal) to 4 (tetrahedral), 6 (cubic), 8, 10, 12 (dense hexagonal). These structural changes are in good agreement with the critical densities established in experimental studies of snow densification and the physical properties of snow. It is shown that the model presented allows us to estimate the mechanical properties of ice-porous media: Young’s modulus, Poisson’s ratio and strength.

scholarly journals Foam Quality of Foams Formed on Capillaries and Porous Media Systems

2021 ◽  
Vol 5 (1) ◽  
pp. 10
Author(s):  
Victor Starov ◽  
Anna Trybala ◽  
Phillip Johnson ◽  
Mauro Vaccaro
Keyword(s):  
Porous Media ◽  
Oil Recovery ◽  
Volume Fraction ◽  
Foam Height ◽  
Liquid Volume ◽  
Foam Formation ◽  
Liquid Volume Fraction ◽  
Wide Range ◽  
Soft Porous Media

Foams are of great importance as a result of their expansive presence in everyday life—they are used in the food, cosmetic, and process industries, and in detergency, oil recovery, and firefighting. There is a little understanding of foam formation using soft porous media in terms of the quality of foam and foam formation. Interaction of foams with porous media has recently been investigated in a study by Arjmandi-Tash et al., where three different regimes of foam drainage in contact with porous media were observed. In this study, the amount of foam generated using porous media with surfactant solutions is investigated. The aim is to understand the quality of foam produced using porous media. The effect of capillary sizes and arrangement of porous in porous media has on the quality of foam is investigated. This is then followed by the use of soft porous media for foam formation to understand how the foam is generated on the surface of the porous media and the effect that different conditions (such as concentration) have on the quality of the foam. The quality of foam is a blanket term for bubble size, liquid volume fraction, and stability of the foam. The liquid volume fraction is calculated using a homemade dynamic foam analyser, which is used to obtain the distribution of liquid volume fraction along with the foam height. Soft porous media does not influence substantially the rate of decay of foam produced, however, it decreases the average diameter of the bubbles, whilst increasing the range of bubble sizes due to the wide range of pore sizes present in the soft porous media. The foam analyser showed the expected behaviour that, as the foam decays and becomes drier, the liquid volume fraction of the foam falls, and therefore the conductivity of foam also decreases, indicating the usefulness of the home-made device for future investigations.

scholarly journals A Generalized Approach for Evaluating the Mechanical Properties of Polymer Nanocomposites Reinforced with Spherical Fillers

Nanomaterials ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 830
Author(s):  
Julio Cesar Martinez-Garcia ◽  
Alexandre Serraïma-Ferrer ◽  
Aitor Lopeandía-Fernández ◽  
Marco Lattuada ◽  
Janak Sapkota ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Polymeric Nanocomposites ◽  
Mechanical Reinforcement ◽  
Future Studies ◽  
Three Phase ◽  
Theoretical Predictions ◽  
Filler Network ◽  
New Research ◽  
Good Agreement ◽  
Research Avenue

In this work, the effective mechanical reinforcement of polymeric nanocomposites containing spherical particle fillers is predicted based on a generalized analytical three-phase-series-parallel model, considering the concepts of percolation and the interfacial glassy region. While the concept of percolation is solely taken as a contribution of the filler-network, we herein show that the glassy interphase between filler and matrix, which is often in the nanometers range, is also to be considered while interpreting enhanced mechanical properties of particulate filled polymeric nanocomposites. To demonstrate the relevance of the proposed generalized equation, we have fitted several experimental results which show a good agreement with theoretical predictions. Thus, the approach presented here can be valuable to elucidate new possible conceptual routes for the creation of new materials with fundamental technological applications and can open a new research avenue for future studies.

scholarly journals Heat Treatment Evaluation for the Camshafts Production of ADI Low Alloyed with Vanadium

Metals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1036
Author(s):  
Eduardo Colin García ◽  
Alejandro Cruz Ramírez ◽  
Guillermo Reyes Castellanos ◽  
José Federico Chávez Alcalá ◽  
Jaime Téllez Ramírez ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Tensile Strength ◽  
Ductile Iron ◽  
Volume Fraction ◽  
Energy Impact ◽  
Treatment Conditions ◽  
Mold Casting ◽  
Grade 3 ◽  
Good Agreement

Ductile iron camshafts low alloyed with 0.2 and 0.3 wt % vanadium were produced by one of the largest manufacturers of the ductile iron camshafts in México “ARBOMEX S.A de C.V” by a phenolic urethane no-bake sand mold casting method. During functioning, camshafts are subject to bending and torsional stresses, and the lobe surfaces are highly loaded. Thus, high toughness and wear resistance are essential for this component. In this work, two austempering ductile iron heat treatments were evaluated to increase the mechanical properties of tensile strength, hardness, and toughness of the ductile iron camshaft low alloyed with vanadium. The austempering process was held at 265 and 305 °C and austempering times of 30, 60, 90, and 120 min. The volume fraction of high-carbon austenite was determined for the heat treatment conditions by XRD measurements. The ausferritic matrix was determined in 90 min for both austempering temperatures, having a good agreement with the microstructural and hardness evolution as the austempering time increased. The mechanical properties of tensile strength, hardness, and toughness were evaluated from samples obtained from the camshaft and the standard Keel block. The highest mechanical properties were obtained for the austempering heat treatment of 265 °C for 90 min for the ADI containing 0.3 wt % V. The tensile and yield strength were 1200 and 1051 MPa, respectively, while the hardness and the energy impact values were of 47 HRC and 26 J; these values are in the range expected for an ADI grade 3.

scholarly journals Seasonal Estimates and Uncertainties of Snow Accumulation from CloudSat Precipitation Retrievals

Atmosphere ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 363
Author(s):  
George Duffy ◽  
Fraser King ◽  
Ralf Bennartz ◽  
Christopher G. Fletcher
Keyword(s):  
Time Scales ◽  
Snow Water Equivalent ◽  
Spatial Scales ◽  
Snow Accumulation ◽  
High Latitudes ◽  
Percentage Points ◽  
Snow Water ◽  
Time Periods ◽  
Predicted Values ◽  
Good Agreement

CloudSat is often the only measurement of snowfall rate available at high latitudes, making it a valuable tool for understanding snow climatology. The capability of CloudSat to provide information on seasonal and subseasonal time scales, however, has yet to be explored. In this study, we use subsampled reanalysis estimates to predict the uncertainties of CloudSat snow water equivalent (SWE) accumulation measurements at various space and time resolutions. An idealized/simulated subsampling model predicts that CloudSat may provide seasonal SWE estimates with median percent errors below 50% at spatial scales as small as 2° × 2°. By converting these predictions to percent differences, we can evaluate CloudSat snowfall accumulations against a blend of gridded SWE measurements during frozen time periods. Our predictions are in good agreement with results. The 25th, 50th, and 75th percentiles of the percent differences between the two measurements all match predicted values within eight percentage points. We interpret these results to suggest that CloudSat snowfall estimates are in sufficient agreement with other, thoroughly vetted, gridded SWE products. This implies that CloudSat may provide useful estimates of snow accumulation over remote regions within seasonal time scales.

The Role of Porous Media in Homogenization of High Pressure Diesel Fuel Spray Combustion

2013 ◽  
Vol 136 (1) ◽  
Author(s):  
Navid Shahangian ◽  
Damon Honnery ◽  
Jamil Ghojel
Keyword(s):  
High Pressure ◽  
Porous Media ◽  
High Speed ◽  
Fuel Spray ◽  
Compression Ignition Engines ◽  
System Pressure ◽  
Novel Approach ◽  
Air Mixing ◽  
The Media

Interest is growing in the benefits of homogeneous charge compression ignition engines. In this paper, we investigate a novel approach to the development of a homogenous charge-like environment through the use of porous media. The primary purpose of the media is to enhance the spread as well as the evaporation process of the high pressure fuel spray to achieve charge homogenization. In this paper, we show through high speed visualizations of both cold and hot spray events, how porous media interactions can give rise to greater fuel air mixing and what role system pressure and temperature plays in further enhancing this process.

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