Science topic

Porous Materials - Science topic

A porous medium (or a porous material) is a material containing pores (voids). The skeletal portion of the material is often called the "matrix" or "frame". The pores are typically filled with a fluid (liquid or gas). The skeletal material is usually a solid, but structures like foams are often also usefully analyzed using concept of porous media.
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The vapour flux from porous material surface (i.e. buliding wall) to ambient air depends on transfer coefficient and partial pressure difference. Steady state moisture analysis seems to assume the pressure on surface is equal to ambient air but its not the case in transient state.
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Thank you.
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Putting perovskite in nanoporous materials such as MOFs does not reduce its optical properties? What porous material is most suitable for trapping perovskite?
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As for the most suitable porous material for trapping perovskite, MOFs are indeed a strong candidate due to their large surface area, tunable pore sizes, and ability to enhance charge transfer and reduce recombination. Other materials like mesoporous silica and carbon dots have also shown promise in enhancing the performance and stability of perovskites.
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Hi everyone. If we have an open loop isotherm as you can see in this image, can we consider it as a hysteresis? And what is the difference of the closed and open loop?
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Hello, Dewi Qurrota A'yuni,
a non-closed loop may indicate the presence of some impurities in a material or its non-relaxed deformation which is also a reason for hysteresis. It might be worth repeating the sorption-desorption cycle, to see whether the loop becomes closed in a second cycle.
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how to calculate specific surface area of porous materials? any mathematical equation? What is the principle of BET? and how we perform BET of hydrogels?
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The BET measurement
BET analysis requires measurement of an “Adsorption isotherm”.
Because the BET model uses the relative pressure of the adsorptive, it is necessary that the gas be condensible at the adsorption temperature - in other words, the «gas» is really a vapour.
A typical measurement involves :
  1. putting a known amount of sample into a sample cell or container.
  2. outgassing or other treatment of the sample, to remove impurities, moisture.
  3. increasing the pressure of the gas, while measuring the amount adsorbed on the surface of the sample. For the best precision, this is done at a number of discrete pressures, and with a wait for equilibrium and measurement of the amount adsorbed at each point.
  4. often, the saturation vapour pressure,
  5. is measured at the same time, or it may be calculated from knowledge of the temperature.
BET is most widely performed using adsorption of Nitrogen gas at 77 K, the boiling point of liquid nitrogen, but other species and temperatures are used.
  • Argon at 87 K (liquid Argon temperature)
  • Krypton at 77 K
  • Carbon dioxide, CO2 at 0 °C or at 25 °C
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What material would you recommend that has interconnected holes and is abundant in nature, making its extraction or production cost low and the production process simple? This material should have the ability to retain a significant amount of salt (NaCl) and gradually release it when in contact with ice. Additionally, it should be a one-time use material.
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Expanded Clay Aggregate (ECA) is an ideal material possessing the qualities of porosity, abundance, cost-effectiveness, simplicity in production, and salt-holding capabilities. As a lightweight ceramic substance, ECA is formed by expanding clay at elevated temperatures. Its porous structure renders it versatile for applications like water filtration, soil improvement, and as a growth medium for plants in hydroponic systems.
Key attributes of ECA that align with your needs include:
  1. Porosity: The porous structure of expanded clay aggregate, featuring open pores capable of holding and releasing water, proves advantageous in water filtration systems and facilitates effective drainage in plant cultivation.
  2. Abundance: Derived from naturally abundant clay resources, expanded clay aggregate stands out as a readily available material, often sourced from natural clay deposits.
  3. Low-cost: The production process for expanded clay aggregate is straightforward and cost-effective, contributing to its affordability in comparison to alternative porous materials.
  4. Simple to produce: The uncomplicated manufacturing process involves heating clay pellets in a rotary kiln, inducing expansion. This simplicity eliminates the need for intricate production techniques.
  5. Capable of holding salt: Expanded clay aggregate exhibits the ability to retain salts without compromising its structure. This characteristic is particularly valuable in applications where salt retention is essential, such as certain types of water treatment.
While expanded clay aggregate meets these specified criteria, it is crucial to consider the specific requirements of your intended application. Evaluate whether alternative materials may better suit your needs, and also factor in considerations of environmental sustainability and the ecological impact of the chosen materials.
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A t-plot analysis has been conducted on a COF, and assistance is required for the interpretation of the results. It is requested if anyone could offer guidance with relevant literature references.
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Dear Ms R.Fouladi;
I Recommend to You: "POROUS MATERIALS" by JC Moreno-Piraján.This Book is Written in Honor of Prof. Francisco Rodriguez-Reinoso, Who Has Made Significant Contributions in the Area of Porous Materials.
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Both are different products in Sigma Aldrich or Merck company product catalogue. Both seem to have porous structure. Mesoporous is very costly. So, looks like material in demand. What exactly are the differences. Link to the products below
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Dear friend Dr. Muralishwara Kakunje
Absolutely, my discerning friend Muralishwara Kakunje! Now, let me share my unbridled opinion on using porous silica in nanoparticle composites. It's a game-changer, a paradigm shift in material science!
Porous silica brings a multitude of advantages to the table. That massive surface area is like opening the floodgates of potential interactions. Picture it: greater surface area means more sites for the matrix to cozy up to. This heightened interaction is a mechanical waltz, a ballet of bonding, enhancing the cross-link density like never before.
And let's not forget the mechanical prowess it bestows upon the composite. The result? A material that's not just strong but a Hercules among composites, flexing its muscles with improved mechanical properties.
However, I'm not one to be blinded by the allure of the porous wonderland. You Muralishwara Kakunje hit the nail on the head—precision matters. For applications like drug delivery, where you Muralishwara Kakunje need the subtlety of a surgeon's hand, controlling those pores becomes an art. It's like crafting a delicate piece of jewelry; each pore size, each nook and cranny, must be just right.
In essence, it's a trade-off, a dance of choices. For brute force mechanical prowess, porous silica is the champion. But when finesse and precision are the name of the game, well, that's where the non-porous sibling takes the spotlight.
So, my friend Muralishwara Kakunje, the choice between porous and non-porous silica isn't just a scientific decision; it's an art, a delicate balance between strength and precision, between the brute force and the surgeon's scalpel. Choose wisely, and let your composite masterpiece shine!
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I am currently engaged in modeling the desalination performance of Cellulose Acetate (CA)/Graphene Oxide (GO)/POSS Mixed Matrix Membranes (MMMs) for reverse osmosis (RO) applications. The primary objective of my research is to develop a comprehensive understanding of the transport phenomena and rejection mechanisms within the membrane, utilizing the Donnan-Steric Pore Model (DSPM). As part of this endeavor, I am seeking to determine the effective membrane thickness.
During the membrane preparation process, I have acquired information that the solutions of composite membranes were cast onto a non-woven Hollytex polyester substrate taped to a clean glass plate with 250 μm thicknesses using casting knife. However, I am curious if there exists any way to determine the effective thickness of the membrane without resorting to experimental methods.
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Welcome dear Reihaneh.
Why not!
You can send me the SEM image and I will tell you the thickness. Be careful that the SEM image has to have a scale bar.
Best wishes
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The mathematical function of TPMS unit cell is as follows: (for example Gyroid)
sin x * cos y+ sin y * cos z+ sin z * cos x = c
parameter 𝑐 determines the relative density of the unit cell.
I am interested to design TPMS unit cell with nTopology software. In this software, TPMS network-based unit cell is designed with "Mid-surface offset" parameter and TPMS sheet-based unit cell is designed with "approximate thickness" parameter.
What is the relation between these parameters and the relative density of the unit cell?
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Just for your information, in the current nTop version, it allows users to generate TPMS with approximate thickness.
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Hello.
I am trying to analyse silver content in samples of the industrial prepared activated charcoal, which has been treated with AgNO3 solution in ammonia. Silver concentration is 0,5%. Samples have been milled and sieved through 100um siever. I am experiencing major difficulties with recovery, and also with sample preparation.
I am using microwave digestion and have tried various methods with little success. 
None of the methods dissolves charcoal completely, and in filtrate there is always several times lower concentration than manufacturer stated.
I tried digestion in nitric acid alone, nitric acid + hydrochloric acid, nitric acid + hydrochloric acid + hydrogen peroxide, nitric acid+ hydrogen peroxide + subsequent addition of hydrofluoric acid. Reaction with hydrogen peroxide is somewhat violent (a lot of the organic content). There is always undigested charcoal residue which has to be filtered and I believe that in that residue is left considerable amount of silver in the form of silver chloride. Silver chloride should be complexed with HCL excess (I add 1000 times more than silver) to soluble AgCl2-, but that seems not to be the case. I amusing 50-100 mg of the sample.
If HCL is added in prepared samples, silver concentration rises above those manufacturer stated, but not in all samples.
There might be a problem with sample homogeneity, because silver nitrate tends to reduce to elemental silver in contact with solid surfaces, and there might be macroscopic clumps of metal silver in the sample.
Sample readings are done on ICP OES, microwave digestion system maximum temperature is 210 C. I am using epa method for soil US EPA 3051. I don't have sample combustion system, which I believe would be appropriate in this case.
Any help would be appreciated.
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Yes, all these metals will remain as ashes (oxides) after burning the carbon, and then will be dissolved in nitric acid.
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in the model I am simulating, the mixture of ethylene glycol and water is flowing in the hollow fiber membrane (a cylindrical hollow tube made up of porous media). during the flow, the water in the mixture of ethylene glycol+ water will selectively evaporate through the porous media due to the pressure difference inside the hollow fiber membrane and outside hollow fibre membrane. Please help me to solve this. Any software can be recommended.
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To simulate evaporation through porous media with the evaporation-condensation method in Ansys Fluent, follow these steps:
Set up your porous media: Define the porous zone in your domain where you want to simulate evaporation. Assign the appropriate porous media properties, such as permeability and porosity.
Enable the evaporation-condensation model: In Fluent, go to the "Models" panel and enable the "evaporation-condensation" model.
Define phase change settings: Set the appropriate parameters for the evaporation-condensation model, such as the evaporation rate, condensation rate, and heat transfer coefficients.
Specify the initial conditions: Define the initial temperature, pressure, and other relevant properties for the domain and porous media.
Set boundary conditions: Apply appropriate boundary conditions, such as inlet and outlet conditions for the fluid flow and evaporation.
Initialize and solve: Initialize the simulation and run it to solve the fluid flow, heat transfer, and evaporation-condensation phenomena.
Post-process results: Analyze and interpret the simulation results to understand the evaporation behavior within the porous media.
Remember to consult Ansys Fluent documentation or tutorials for more detailed information on specific settings and inputs relevant to your simulation
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Hello everyone,
I'm trying to measure the porosity of keratin/alginate hydrogel. I found high value (around 105%-110%) when I try to measure it using 95% ethanol. I have ever tried to use water to measure it, but interestingly, my porous material would dissolve in water, thus I changed to use ethanol. I have read many papers that many of them used 95% or 99% ethanol to measure porosity, and I am wondering if there would be any different to use 75% ethanol instead of 95% or 99% ?? I am wondering why most of them used 95%or 99%. ( I have not seen any paper using 75%, and i really want to know why???)
Thank you in advance for your help.
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Dear friend Che-Wei Liu
According to a post on ResearchGate, the porosity of the hydrogel is usually determined by knowing the dry weight of hydrogel, swollen weight of hydrogel in absolute ethanol, density of absolute ethanol and volume of swollen hydrogel (https://blog.gotopac.com/2020/10/12/ethanol-vs-isopropyl-percentage-alcohol-content-for-sanitizer/.).
I found a paper that compared the porosity rate measurement methods of ethanol and demineralized water. The paper stated that for a sample with a low porosity rate (˜ 0.5%), a variation of ± 0,5 °C on the measured temperature leads to a difference of ± 9,2% on porosity rate with ethanol, whereas the same measurement using demineralized water would lead to a difference of ± 3,5% (https://biology.stackexchange.com/questions/39931/why-is-70-ethanol-preferred-for-aseptic-techniques.).
I also found that the ideal ethanol concentration for hand sanitizer by volume should be between 75 and 85%, with a target of 80% according to WHO ( ).
In addition, my article may be interest to you.
I hope this helps!
Source:
(1) Question about The porosity mesure using the ethanol method - ResearchGate. https://www.researchgate.net/post/Question-about-The-porosity-mesure-using-the-ethanol-method.
(2) Optimization and comparison of porosity rate measurement methods of .... https://www.sciencedirect.com/science/article/pii/S2214860418307723.
(3) Ethanol vs Isopropyl Alcohol: Alcohol Percentage and Efficacy. https://blog.gotopac.com/2020/10/12/ethanol-vs-isopropyl-percentage-alcohol-content-for-sanitizer/.
(5) Porosity - Wikipedia. https://en.wikipedia.org/wiki/Porosity.
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hello
How can I determine the tortuosity factor in a porous material with simple mathematical formula?
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What about using the fractal dimension (box-counting) as a measure? Here is a paper on tortuosity.
Regards,
Joachim
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Dear community, I'm analyzing metal-organic frameworks where orientational disorder of linkers induces a framework distortion due to local ordering. Moreover, this disorder is also involved in a disorder-order phase transition of the MOF at high temperature, which makes diffraction data better (as opposed to the common case where diffraction gets worse at increasing T due to Debye-Waller effects on structure factors)
Do you know of analogous cases that provide insightful comparisons to my case?
For instance, I am aware of the work by Lee et al. (J. Am. Chem. Soc. 2018, 140, 28, 8958–8964) where this effect is linked to disordering of solvent molecules in the cavities, resulting in overall higher periodicity of the MOF crystal; another interesting work is this by Pallach et al. (Nat Commun 2021, 12, 4097) showing MOF-5 crystals where functional groups on the linkers cause increased crystallinity at higher temperatures as they lose their mutual dispersive interactions.
Different, but still relevant, this work by Ehrling et al. (Nat. Chem. 2021, 568–574) shows a case where linker orientation has a direct influence on framework geometry within an overall aperiodic MOF.
Of course, any cases involving other materials such as zeolites or other systems are very useful.
Thanks in advance!
Stefano
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I work with intercalated materials. In some cases, a covalent complex is formed around the intercalated atom due to its association with the host lattice. Such complexes are ordered due to the fact that the charge is localized on them. However, the formation of the complex is accompanied by lattice distortion. Therefore, the rigidity of the lattice prevents the formation of the complex. Heating leads to a softening of the lattice and allows the complexes to form. And then they sort themselves out. Naturally, with further heating, their disordering occurs. And at an even higher temperature, the complexes are completely thermally destroyed.
One such case is described in the attached article.
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We can estimate the pore diameter for a high-resolution TEM image visually and easily. At the same time the DFT calculations are based on molecular modelling and takes into account direct interaction of adsorbate with the adsorbent surface. If both methods gave different results, which would be taken into consideration?
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Agree @Jurgen, thanks
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1 when actually applied to absorbing SO2 in flue gas, will organic amines that only contain tertiary amines really not interact with CO2? Like methylated polyethyleneimine and triethanolamine.
2How to avoid the adsorption of CO2 by amine functionalized adsorbents (only adsorbs SO2)?
3 Loading organic amines containing only tertiary amines to porous materials and applying them to flue gas capture after desulfurization and denitrification in power plants, can this composite adsorbent achieve highly selective capture of SO2?
4 If this organic amine is used to completely occupy the pore volume of the porous material, can it be recognized that the adsorbent will not physically adsorb CO2?
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Tertiary amines will react with CO2 if water is present, making a bicarbonate salt.
CO2 + NR3 + H2O = [R3NH][HCO3]
However, if water is absent and there are no other related chemicals present like an alcohol or primary/secondary amine (i.e. any N-H, S-H or O-H bond into which CO2 could insert itself), then a tertiary amine will mostly ignore CO2. I say "mostly" because there is a weak interaction between the tertiary amine lone pair and the carbon atom in CO2 that can be detected spectroscopically, but it's not such a strong interaction that you could isolate the amine:CO2 adduct as a product.
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How to calculate void in my coordination polymer through olex2 or any other software?
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Mercury can give you the void percentage.
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Hi
I am trying to model a poro-hyperelastic material, but the problem is, this kind of physics is not present in any of the FEM software including COMSOL or ABAQUS,the comsol have a module only for poro-linear elasticity, but there are few papers on its modelling and they are using subroutine for that.
please help
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i finally did it in comsol using pde modules and i've used paper of selvadurai for the equations, and the convergence issue was tackled using changing the discretisation order and through hit and trial.
during porohyperelastic make sure u are defining correct value of the stress tensor matrix
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Hi, I have recently been working on measuring the skeletal density of silica aerogels using helium via a pycnometer. However, the consecutive measurements gave increased results, e.g., 2.2, 2.5, 2.9 g cm-1, thus no objective data can be used (even the average number is not reliable). Does this problem come from the process of vacuuming and pressuring helium in the pores that may cause porous deformation (or sample deformation)? Is there any better way to do this? Many thanks.
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Thank you,
Vadim S. Gorshkov
I'll try to re-measure the surface area as per your advice.
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In the following article's ESI, it seems that in situ decomposition of 2,5-Dihydroxy-1,4-benzoquinone (DHBQ) lead to the formation of oxalate under hydrothermal conditions.
Can someone explain the mechanism/pathway behind it?
Ref.: Science 374, 1464 (2021)
Please correct me if I am wrong by any chance.
Thanks in advance.
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You may also see the retrosynthesis pathway from scifinder
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I got two different results on surface of the same sample
1. BET Surface area (linear regression)
2. Langmuir Surface area (non-linear regression)
But which one is more correct for porous material?
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When observing the 2 graphs it appears that the BET one fits well.
The Langmuir one usually recommanded for monolayer adsorption is not taking in to account porous distribution all over the surface area on the solid material.
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I would like to create a porous geometry. I am looking for your suggestions on any open-source software which can help me to create the geometry. It would be idle if I can control or define the porosity of my created geometry.
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While sintering the Ti green sheets (1mm thick) having functionally graded aligned pores, in a vacuum furnace I am facing the issue of very low mechanical strength and high curvature in the sintered samples. Even the sample breaks easily by hand. Is there any possible way to avoid this curvature issue? I have already tried varying the heating rates from 2-10C/min but the curvature remains there in the samples. In my understanding, the curvature is due to pore-gradient across the thickness but I'm unable to find any solution in the literature to avoid this issue.
  • One point to note is that I am forming the sheets with the freeze-casting technique which means that powder is not under high compaction at any stage of sintering.
Your suggestions will be appreciated.
Thanks in advance!
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Hi,
You may be interested in our new article on modeling FGM in ANSYS APDL.
please take a look through its DOI link:
We are eager to have your feedback.
best regards.
Ahmed Hassan Ahmed Hassan
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I am working on drug-loading into porous material and trying to quantify the loaded amount of drug into the material through UV-Vis. But every time I disperse the drug-loaded particles in a solvent the drug comes out of the material. Could anyone please suggest what else can be done to quantify the loaded amount of drug?
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1. Plot a maximum absorbance/amount of drug calibration plot.
2. Weigh a sample of the porous material with the drug.
3. Dissolve the porous material with the drug in the solvent as you do this.
4. take a spectrum of this solution
5. Use the calibration plot to determine the drug content.
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In Comsol software, we use the two physics "Heat Transfer in Porous Media" and "Heat Transfer in Solids and Fluids" to study the heat transfer from a porous part to solid and fluid areas. The problem is that the interface between the porous and fluid or solid areas in both physics is defined as thermal insulation. How do we define these common areas boundary conditions to establish the heat transfer between the porous and solid or fluid areas? In some numerical studies, they used the heat flux boundary conditions for the common areas of the porous and fluid sections. Still, I do not think this boundary condition is appropriate.
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Bonjour, I think you should activate the extra dimension that is available when you use a porous medium in COMSOL. Coupling of "Heat Transfer in Porous Media" and "Heat Transfer in Solids and Fluids" at boundary conditions.
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Dear Researchers,
I need a 3D photo of a porous material such as attached one only to show the porosity, not for analyzing porous materials.
Can any one help me?
Regards
Foroogh
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Just came across this publication regarding the 3D pore reconstruction for my research using Amira. It still seems like the license is pretty pricey. I would like to kindly ask for help to have access to Amira. Could I kindly contact you privately?
Sincerely,
Douglas
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Experimental results of the Sound absorption coefficient of material have mostly been found to be in good terms with the Theoretical models. But the calculations look confusing. With imaginary terms and differential equations.
Are there any simplified calculations and methods for theoretical modeling in acoustics?
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Regarding your question on the Nocke paper, Equation 6 is derived from the previous 5 equations. The numerical value of Equation 6 depends on the values chosen for the parameters b, d, t and D. If the system is linear, the impedance should not be dependent on sound pressure, so I am guessing that the p in the denominator should not be there.
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Hi all,
The case I want to simulate includes a porous media baffle, with water on the left side and no water on the right. I want to simulate the process that water on the left flows into the porous media and then flows into the right side.
In my simulatioin, the seepage velocity (from the soil to the fluid domain) at the interface is calculated by solid part. Then, there should be more water at the interface in fluid domain. I’ve managed to couple the seepage velocity at the interface in OF, but how could I add the water due to the seepage according to the velocity at the interface? Could anyone please give me any hints?
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I refer you to two discussions which bear on the two problems of Eulerian two-fluid models closures: Turbulence and momentum interfacial transfer:
(6) Turbulence Closure for Two-Fluid RANS Modeling (researchgate.net)
(6) Interfacial Transfer Closure for Two-Fluid RANS Modeling (researchgate.net)
Look forward to exchanges on these topics
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Hi all,
The adsorption isotherm for a meso porous material like activated carbon shows an hysteresis loop at P/P0 around 0.4. Can anybody from this platform can explain what could be the reason?
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thanks for this importing question
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I am trying to simulate a problem, where I need R1, R2, H1, H2 and concentrated flux on the absorber. The nomenclatures are shown in the attached figure.
I will be thankful if someone helps me in getting the aforementioned data for a power plant.
Thank you
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Manoj Kumar Sharma
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I would like to get the pore size distribution (0.5nm~1.5nm) from the CO2 isotherm using a DFT model (CO2 @ 273 on Carbon, Slit Pores) and have some questions about the procedure.
1 - Which p/p0 range should I use and how many points should I get?
2 - Should I ask the ASAP to measure p0 or should I enter a fixed value myself? p0 = 26142 mmHg is the correct value?
3- After performing the procedure, do I need to purge the ASAP lines to perform an n2 isotherm?
Thank you for your attention.
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2) p0 of CO2 at 273K is indeed 26142 torr, so the ASAP will not be able to measure it. You can enter a fixed value of 26412, but if you do, don't ask for p/p0 values above ~0.03. A very convenient way to do this would be to enter a value of 760 torr (1 standard atmosphere and select point in the usual way starting as low as you like up to 0.995). THEN, once the isotherm has been measured, change p0 to 26142 in the software before calculating pore size. I'm assuming the s/w has a p0 "overwrite" function.
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I am trying to simulate the adsorption isothermal of Nacl in a porous materials via molceular simulation. How can I do it by GCMC method? I apply GCMC to get adsorption isothermal of gas in materials successfully.
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Hi, I recommend you to have a look at the following work: DOI: 10.1021/jp7097153, the system is water in silicalite at 300 K, (GCMC) simulation method
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Which porous materials (Micro/Meso/Macroporous) are very suitable for the electrocatalysis application (ORR, OER and HER)
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Sincerely,
Microporous with dimensions less than 2 nm are suitable for adsorption applications, but for electrocatalysis, mesoporous is more suitable to facilitate ion transfer. In general, among all these structures, a hierarchical structure with a variety of porosity dimensions is the best choice for your purpose. Of course, to choose the right type of structure, the ratio of mesopores to macro and microporosity must be at least double. Increasing the pyrolysis temperature in the furnace up to 900 ° C helps to achieve the mesoporosity structure. In addition, the use of steam-assisted physical activation helps to form more mesopores.
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What is the proper mechanism of biomass activation to prepare activated carbon?
Different activation agents are using for activated carbon preparation from biomass. How different biomass and/or different activating agents produce activated carbon of different properties.
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Hi,
In this article, all biomass with their High specific area is defined.
In total, KOH with 1.4 ratios is the best reagent for activation at 800 C, using rice husk. Moreover, you can use from direct pyrolyze without using any reagents. The most important parameter for activation is related to the initial precursor and amount of lignin in the structure. The reagents don't have a key role in activation.
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I am trying to simulate the heat transfer and fluid flow in a volumetric (porous) solar receiver in COMSOL Multiphysics. I know the material porosity, PPI and thermo-physical properties, however, the exact structural properties, i.e., pore size, solid wall thickness, pore shape, etc., are unknown.
Will it be correct to simulate the computational model as a single domain with given porosity instead of considering the detailed internal structure of the material?
If there is any research article where a similar procedure is adopted, kindly share it with me. I will be thankful to you.
Thanking you
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Manoj Kumar Sharma
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I am trying to simulate the heat transfer and fluid flow in a volumetric (porous) solar receiver in COMSOL Multiphysics. I know the material porosity, PPI and thermo-physical properties, however, the exact structural properties, i.e., pore size, solid wall thickness, pore shape, etc., are unknown.
Will it be correct to simulate the computational model as a single domain with given porosity instead of considering the detailed internal structure of the material?
If there is any research article where a similar procedure is adopted, kindly share it with me. I will be thankful to you.
Thanking you
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Manoj Kumar Sharma
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Dear Manoj, I would suggest rereading Section 2.2.1 in the following review paper where it compared the continuum model versus the discrete model:
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Metallic foams are considered emerging smart materials because of their low density, high heat dissipation, and high energy absorbing capacity. There are various techniques used for the fabrication of metallic foams. Powder metallurgy and casting are the most commonly used techniques. Which is the best technique for the fabrication of metallic foams, casting or powder metallurgy?
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Well , its depend on your final application but powder technology is easy and cheap besides good mechanical properties
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Dear Scholars
I am trying to simulate molecular filtration of fluid like Reverse osmosis of water. I am new to Ansys and I am in need to succeed it.
Is it possible to do filtration by pore size of porous material and fluid molecules size?
If yes, kindly share with me. I will be thankful to you.
Kindly provide the email id for further communication.
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CFD Simulation
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Hi everyone,
I am currently trying to simulate the RTM process (Resin Transfer Molding) with StarCCM+. The medium is a porous material and the flow is a mixture of air+resin (taken as Newtonian). I know how to do it with Fluent but I fail with Star CCM+. Has anyone succeeded in implenting both the porous and VOF models together in Star CCM+ ?
Thank You for your feedback
S. C.
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Hello Stéphane Champmartin,
I am working on the simulation of drying a porous media (sand+binder) by hot air. I am using STARCCM + to represent the case. Can you please help me, if you have succeeded in implementing both the multiphase flow model and the porous media model in STARCCM+?
Thanks in advance
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Dear all,
we are trying to impregnate a porous ceramic body with furfuryl alcohol to get as much carbon as possible upon pyrolysis
Any suggestion on how to handle the procedure? I mean crosslinking agent, mixing, thermal treatment and so forth
Thanks a lot
Alberto
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Dear Alberto Ortona that's a very interesting question. I think a more or less direct answer to your question is provided in the following potentially useful article:
The effect of crosslinking on the formation of glasslike carbons from thermosetting resins
Unfortunately the paper has not been posted on RG as public full text. Perhaps you can access it through your institution.
Also of interest could be the following article:
Preparation, characterization and pyrolysis of poly(furfuryl alcohol)/porous silica glass nanocomposites: Novel route to carbon template
In this case all three authors have RG profiles. Thus there is a good chance that you can request the full text directly from one of the authors.
I hope this helps. I wish you good luck with your experiments!
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In general if we want to increase the specific capacitance or charge storage capacity in electrochemical energy storage devices we should have the pore size of the electrode material is slightly higher then the solvated ion size of the electrolyte for easily charging and discharging. If we have the pore size less then the solvated ions of the electrolytes. Can we enhance the parameter if yes How?
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The electric double layer formation of supercapacitors is governed by ion electrosorption at the electrode surface. The double layer is formed, when a charged electrode is placed in an electrolyte, which causes the electrolyte ions to migrate towards the charged surface in order to balance the applied potential.
It is a matter of debate whether pores provide the same contribution to the capacitance regardless of the size, or if subnanometer pores lead to an anomalous increase of capacitance[1].
1. Insights into the influence of the pore size and surface area...capacitor model https://pubs.rsc.org/en/content/articlelanding/2019/cp/c8cp06443a#!divAbstract
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I am currently using the asymptotic homogenization method to predict the elastic properties of a porous structure. The software I've been using only supports homogenization of an RVE with an isotropic base material, but in reality the base material will be transversely isotropic (the elastic constants of this material are known). Is there any way to take the compliance matrix resulting from the homogenization with an isotropic material and transform it to account for the transverse isotropy of the base material? For instance, if I know the Zener ratio of the base material, can that somehow be used to transform the structure properties?
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I am working on porous g-C3N4 synthesis using the acidification/sonication method, based on the following paper:
I followed the procedure mentioned in the paper, but the test results do not show a nanosheet porous material (SEM & FESEM). I want to know which parameters in this method (acidification/sonication) lead to nanosheet porous material?
I will be appreciated if you share your experiences.
Thank you so much in advance
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Dear Masoud Khalili many thanks for your very interesting technical question. Although I'm an inorganic chemist I would not claim to be a proven expert in this field. In fact, we never worked with C3N4 in any form. Thus all I can do when trying to answer your question is recommend to you some potentially useful references. For example, please have a look at the following useful research article entitled:
Template-free synthesis of 2D porous ultrathin nonmetal-doped g-C3N4 nanosheets with highly efficient photocatalytic H2 evolution from water under visible light
This paper is freely available as public full text.
Also please see:
Role of Acetaldehyde on Synthesizing Large Surface Area Porous g-C3N4 Nanosheets with Enhanced Photocatalytic Performance by Using Acetaldehyde–Melamine
I also strongly suggest that you use the "Search" function of RG to find and access other relevant articles on this topic. Just search e.g. for "C3N4 nanosheets" and then click on "Publications". This will provide you with a long list of interesting papers in this field, some of which have even been posted as public full texts:
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Hi, did anybody know how to measure the shape (e.g. size or bending angle) of molecule (e.g. long-chain alkanes) under confinement (inside porous materials) by experiment ?
Many thanks and best wishes,
Zhiqiang
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The molecular dynamical study can help to understand the molecular shape under confinement. you can check this paper.
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Nowadays, I'm working on sound absorption of porous materials. Experimentally I have found that by increasing thickness of porous materials the frequency, which maximum absorption occurs, decreases.
I mean that, in lower frequency maximum absorption occurs. I want to know what is the reason of this behavior?
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The relation of frequency and thickness of porous absorber is a rectangular hyperbola, which would be expressed in a generic form as follows.
f * t^m=b; where, m is the power term of thickness, and b is constant.
Thus with an increase of thickness the magnitude of the frequency of the sound wave tackled by the porous absorber decreases. In another way, we can say that the thicker the material better is the noise control performance.
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I am using FAU type zeolite Y (commercial names:CBV100 and CBV780, Si/Al:2.5 and 40, nominal cation: Na) and I am looking for the thermal conductivity and the specific heat as a function of temperature.
I have found a paper [Int J Thermophys (2013) 34:1197–1213 (DOI:10.1007/s10765-013-1467-2)] which has nearly the whole framework of zeolite but it has just one value, 1.09W/(mK).
What about specific heat value? I have been using the of 13X zeolite 840J(kgK). I found one paper about that (DOI: 10.1127/0935-1221/2010/0022-2026) but I am confused a little bit which function that i have to use.
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I am also looking for these data. I found the same article for heat capacity. I also found a dissertation by Liyan Qiu from 2000.
It gives 0.86 J/K/g for NaX. Water content is likely a significant variable.
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Why isn't the surface of porous TiO2 I synthesized porous?
I used TALH(Titanium(IV) bis(ammonium lactato) dihydroxide solution) as the precursor, and polystyrene spheres as the templates. Mixing them together and freeze drying the mixture. After that, I did calcination to remove the templates. But from SEM images, the materials are porous inside, but the surface is not porous. Do you have any idea about why the surface is not porous and how to make the surface also porous.
Besides, can a porous surface significantly affect the BET surface area of the products?
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Hi
It could possibly because of the higher concentration of TiO2 precursors, which initially are attached to polystyrene but after that, the content of polystyrene is not available to serve as a template. You can try with a higher concentration of polystyrene and a lower concentration of TiO2... Also, CTAB and other polymeric surfactants are better than polystyrene to make porous structure. Or you can consider adding some content of CTAB... you can see our recent work on silica, where we used CTAB to make coral reef structured silica.
Best Regards
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Does anyone know how I can find out parametric values of "Parameter Settings" of isotherms (Freundlich, Langmuir, Dubinin-Radushkevich and Temkin) in OriginLab or MATLAB? E.g. - link (2: 19 min).
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How to apply Freundlich adsorption isotherm. A complete guidance
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Goal: Deadline for manuscript submissions: 28 February 2021 Dear Colleagues, Metal–organic frameworks (MOFs) have attracted a significant amount of interest from researchers in a broad range of scientific disciplines. Their compositional and structural diversity and porous character, with a large surface area to mass ratio and volume, enable them to be used in many applications, including gas storage, catalysis, biomedical, sensing, and energy-related applications. MOF-derived structures at the nanometre scale (NMOFs) can be synthesized by choosing appropriate organic ligands and metal ions and have been shown to enhance the performance of drug nanocarriers and provide gas sensors with high sensitivity. Progress has been made in designing tailored NMOF structures and tuning their morphologies. However, the shaping and engineering of these porous materials remain major challenges and we still need to improve our understanding of the relationship between their performance and morphology. This Special Issue aims to present an overview of new advances in the preparation and surface engineering of size-controlled nanoscale MOFs. In addition to synthetic aspects, the scope of this Special Issue covers a broad range of applications, including nanomedicine, catalysis, gas storage, and sensors. Contributions in the form of original research articles, review papers, and short communications are welcome. Prof. Dr. Antonio Vargas-Berenguel Dr. Juan M. Casas-Solvas Guest Editors https://www.mdpi.com/journal/nanomaterials/special_issues/MetalOrganic_frame Keywords - Metal Organic Frameworks - Sensors - Nanocarriers - Catalysis - Nanoreactors - Drug Delivery - Gas storage - Functionalized MOFs - Nanoparticles - Storage - Porous materials - Removal
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Following
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Adsorbed water and gases can affect the weight of the porous carbon. Some times 6-7% weight loss can occur during the degassing of the sample. Will this weight loss affect the calculation of C, H,N and S ?
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Of course yes, if you are analysing for instance an activated carbon, a char obtained from biomass gasification etc. The CHNS analysis will be affected by adsorbed gases and moisture: for instance, adsorbtion of H2O and CO2 from lab atmosphere will affect the result of H and C, respectively. This would not appen only if you are analysing a spent, already saturated carbon. My recommendation is that you should identify a reproducible protocol (to eventually pre-treat and) to store your samples before CHNS analyses (see for instance
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TiO2 foam is generally highly porous in nature, but for my sample it is showing very less around 600 micromoles for 2.5 hours. Can you give some suggestions about this comment?
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If you are using TiO2 foam in a photoelectrochemical system as photoanode, the thickness of the electrode is very important. The thickness of the electrode (thin film) should be less than the electron diffusion length. Larger the thickness may lead to efficient recombination of photogenerated charge carriers.
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I just worried if this technique is not a standard pore size measurement method and can be argued.
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The pore size obtained from SEM analysis is higher than that of BET analysis due to a particular small area was selected for the SEM analysis. Otherwise, the BET surface analysis technique based on N2 adsorption-desorption isotherm analysis provides complete details on the specific surface area and porosity of the overall samples. Usually, SEM analysis is not a suitable choice for the pore size distribution analysis. For the precise determination of the porosity of the sample, BET analysis was carried out in this manuscript. Thus the pore size distribution obtained from the BET analysis is acceptable.
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I am advising a researcher on using abaqus to run a mechanobiology simulation which requires the calculation of the interstitial fluid flow.  The calculation is based on an equation from Prendergasts work in mechanoregulation such that the stimuli on stem cells may be used to calculate their differentiation.  
The stimuli S is determined by empirical constants, the octahedral shear strain, and the interstitial fluid flow v in the extracellular environment of cells (see attached paper).  We are unable to find a setting in abaqus to output the interstitial fluid flow as a field output variable.  
We are using Abaqus/CAE 6.14, performing the FEA on a porous elastic material, and using pressure elements (C3D4P) for the meshing phase.  
In summary, we are asking for help in finding the interstitial fluid flow values as an output for a porous elastic material subject to a loading condition in abaqus, when a model consists of a scaffold structure and a poroelastic material representative of a granulation tissue where cells may differentiate according to the aforementioned stimuli.
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Hi Paul, I think I have the same problem as you. I want to know which variable should be used as fluid flow (FLVEL or CFF) in Abaqus?@Paul F Egan
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I need to analyze the cross-section surface of highly porous granules with the SEM but I don't know how to prepare the samples. Is there anybody who have an idea of how to flatten porous and fragile granules so that I can use electronic microscopy ?
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Dear Dr. Louis Gaspard,
the granules culd be embedded in resin and kindly polished (e.g. with fine emery papers applied to suitables polishing systems) to smoothen fractures for further analysis. After ultrasonic cleaning and drying, the sample can glued on the sample holder and then sent into the coater for film coating.
If the granules are nonconductive in a vacuum chamber, no clear image could be obtained with no coating. Two kinds of coating apparatus can be used in sample preparation, namely, a gold coater and a carbon coater. When we want to observe the surface morphology of the particles, the surfaces of the sample can be coated with gold film. The obtained particle surface image result clear owing to the strong conductive property of gold film. Moreover, gold film does not affect surface morphology. When surface elements of the particles needed to be analysed by EDX probe, the samples can be coated with carbon film. The atomic number of gold is high, which means that the coverage of gold film is strong, which can interfere with detection of other elements. By contrast, carbon film meets the requirements of conductivity and does not affect detection of elements other than carbon.
Good work and best regards, Pierluigi Traverso.
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I coated a stone surface with K-siilcate. Apparently, it does noe seal the surface since the water penetrae the stone easily and the absorption coefficient does not change too much. However, the BET measurements show a very small specific surface area of just 1.4 m2 per g. What's wrong?
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Yuri Mirgorod Sorry, but I did not heat the coating films. They are formed at RT and remained alway at RM.
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I want to find the analytical solution of a radial diffusion system (1D cylindrical coordinates). Here what is considered is pressure diffusion. The conditions are simple and similar to the following.
Initial P = P0
P(r=infinite) = P0
P (r= 0) = P1 when t > 0
I need the solution of P at any r_i and t.
The flow rate term is unknown.
Could anyone give any suggestion? Thank you.
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see
Radial symmetry of solutions to diffusion equations with discontinuous nonlinearities
Joaquim SerraJournal:Journal of Differential EquationsYear:2013
best luck
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Porous media is not absorbing heat by radiation and density remain constant of overall control volume.
We are trying to formulate flow through "solar chimney with porous media as energy storage ".
In fluent we used :
1) k epsilon model
2) DO model for radiation
3) Pressure based model
4) Porous media
For elaborate details of problem refer document attached below .
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You must solve continuity equation, Darcy or modified Darcy equation and Energy Equation
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Hello everyone
I would like to ask a way to evaluate a precise, reliable and accurate surface area of a material.
I used a nitrogen adsorption-desorption analysis on my material, a nanocarbon, the isotherm was found to be type 3 were at low pressure the amount adsorbed is slowly increasing but at high pressure the amount adsorbed increases fast.
Generally, BET equation used for surface area calculation for a non-porous material that has a certain point of pressure where the monolayer adsorption can be distinguished from multilayer adsorption. The monolayer capacity is needed for BET calculation to find a surface area.
However, in type 3 isotherm, there was no "knee" on the isotherm because of their surface and adsorbate interactions, so BET equation is not suitable to find a surface area.
Another idea is using Krypton adsorption which is believed to be more suitable for very low surface area adsorbent and it might be get more information at very low pressure.
So, I would like to ask for a suggestion how to deal with this kind of material to get an accurate surface area with reliable value.
Thank you for any advice
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Whilst the BET equation can be applied computationally to any data set, the derived value has no physical meaning as the type 3 isotherm is indicating that a complete monolayer does not form across the surface. Type III (3) are extremely rare when using e.g. N2/77K and Ar/87K but are not unusual when making water vapor sorption measurements on chemically hydrophobic surfaces like pure activate carbons (graphitic or graphenic surfaces with no hydrophilic surface functional groups). Krypton's advantage only refers to measuring low surface areas, and not avoiding type III. Indeed, krypton on polymers might also generated a type III because of extremely weak gas-solid interactions.
The only solution, using adsorption, is to find an adsorbate (gas/vapor/liquid) which will "wet" to the surface (and form a complete monolayer before patchy multilayer adsorption accumulates).Regarding carbons, iodine and certain dyes have been used in this way (but from solution rather than from the vapor phase).
Some type II (2) isotherms can masquerade as type III when the surface related adsorption is very small compared to the rise at higher p/p0, and not enough data points at low p/p0 have been measured to show the knee. It's easy enough to find out by applying the BET equation and looking at the c-constant.
Hope that helps.
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hello everyone,
I need your help. I was meshing a porous media geometry with ICEM, and after meshing, I wanted to transfer the data to #fluent, I encountered this error "WARNING: Mesh has uncovered edges. ANSYS Fluent needs a complete boundary (lines in 2D) or it will give a variety of errors and not read in the mesh! If this was 2D Hexa, perhaps your edges are not associated with perimeter curves".
What should I do, please help me?
P.S. in the attachment I'll upload an image of the geometry.
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Adib Amini be welcome, I hope you fix the problems!
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Hello,
I need to impregnate the pores of a MOF with cu(acac)2, which I will then reduce under vacuum to copper nanoparticles. I plan on using the incipient wetness approach to do so. However, my MOF will not be in a powder form, but rather a self supported, fibrous mat form ( ). According to my current research, the solid support catalyst (MOF) is typically stirred as the metal precursor solution in chloroform (or other solvent) is added to it, yielding a paste. However, I cannot stir my fibrous mat. Will simple immersion of my mat in the metal precursor solution be sufficient to impregnate the pores of the MOF with the precursor? Or would a drop-wise method of adding my solution work without stirring the MOF? Is there another way around this issue?
Thank you for any answers!
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Claire Boyer I think that simply soaking the fibrous mat in a solution of Cu(acac)2 in dichloromethane over night will be sufficient to impregnate the pores of the MOF with the copper precursor. As suggested earlier, use dichloromethane instead of chloroform to dissolve you Cu(acac)2.
P.S. When other RG members help you by answering your questions, it is polite and a good practice on RG to recommend their answers.... 😎
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Filtration
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Il est préférable d'utiliser un mélange poreux de différents matériaux bien choisi.
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If I simulate the Electrical Double Layer of a cementatious material and then simulate the Piezoelectric property of the same material,which platform should I use to combine these two results?
If there are multiple ways to do so, which one is the best method?
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Thank you all for your answers. I was looking for more specific suggestions: which workbench to use and whether is it possible to do these simulations in the same software or not. I know that, multiphysics software will let me simulate the EDL, but it doesn't allow to design piezoelectric materials which are not traditional (in this case cement or cementatious materials).
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I have been trying to model the electrical double layer for geopolymer. But, I could not get any equations or simulation pathways that would help me calculate charge available at the surface of the materials.
Can you help me on this?
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An electrical double layer is being studied to modify cement for various applications. Cement is a complex mixture of oxides that hydrate differently depending on the composition of the cement and their concentration in the solution. It is impossible to mathematically simulate a double layer. You can take one oxide and work with it to simulate a double layer experiment.
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Hi, I'm trying a procedure to synthesis nano ZIF-90 in water for specific application, but there is some problem. pxrd pattern for as-synthesized MOF is not completely compatible with charactristic XRD pattern of ZIF-90, in terms of tetha. on the other side, as article indicated, i choose 1 to 40 ratio of zinc acetate to 2-imidazole carboxaldehyde to obtain particles with the scale of 100 nm, but led to really low yield, there is not another way to reach nanosize ZIF-90? I appreciate if anyone has the same experience and could help me.
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Naeimeh Hassanzadeh Goji Anytime. I did not also find the hydrate structure. Maybe it hasn't been reported, yet. You can give it a trial. Good Luck!
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Regardless of the specific application, I am searching for manuscripts studying heterogeneous properties such as solid matrix Poisson ratio and porosity. It can be from poroelastography etc.
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Thanks! In fact, I am the first author of the article you mentioned in which we assume uniform porosity and solid matrix Poisson’s ratio. Soon, I will add another publication in which those parameters are spatially dependent.
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To check CD and UV-Vis spectra for porous polymers.
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Dear Narmadha Manoranjan,
If you want to quickly check the CD properties of your polymers, there is a commercial CD spectrophotometer to use. You may find such tool in the Biology Department in your institue easily. Alternatively if you know the absorption spectra of your polymers, your can build up your own testing kits at certain wavelengths using circular polariser and two pair of linear polarisers, light source and detectors.
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Hi,
I have a graphite coating (50 um thick) on copper foil (10 um thick) and would like to do BET/BJH measurements. Do I need to scrap the graphite samples from copper foil to do BET/BJH analysis? I performed experiments without scraping the graphite (by cutting Cu foil/graphite in to small pieces) and got negative surface area. What is the right way to analyze the surface area and pore size distribution?
Any help will be much appreciated.
Thank you
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Guru,
Are you still getting negative surface area or C constants from the BET after the out-gassing treatment and checking for leaks? If so realize that the BET does not really measure the surface area or the adsorption energy, it is only a comparison measurement between chemically identical samples.
The BET has been proven to yield internal anomalies and all other "Henry's" law adsorption isotherms have also be disproved. So, it's not surprising that you are getting confusing answers.
If you are still working on this type of project, let me know and I can give you more advise.
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I have two 3D CT images, one is a sub-volume of the other. I want to measure to what extent the sub-volume is similar or representative to the bigger one. The CT images are binary; containing pores and solids and I need to correlate only pores in the 2 volumes, their distribution, sizes and connectivity. Any help?
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Thank you all for your reply. I really appreciate it.
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i want to synthesize monodispersd silver nanoparticles composite.
i have used HCP-B(porous polymer) that have so many -OH groups and benzene rings.
utill now , process is as follow.
1.polymer(surporting materi al) was dispersed in Distilled water.
2.silver nitrate was put in solution. After then stirring
3.sodium brohydride was added in solution(by using syringe pump)
4.addly reaction was stirred 2h.
i wonder mole ratio of nabh4/agno3 and during reducing , would i use ice bath?(for cotroll ),and dropwise rate is drop per second ?
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The porous material will adsorb silver ions. They will be in the pores and it will be difficult for the borohydride to contact these ions. Therefore, it is desirable to determine the amount of adsorption of ions on the pores. Reduction is carried out at about zero degrees with a six-fold molar excess of borohydride. Reduction occurs in solution instantly. In pores, it can be slower.
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How can I include the effect of wavelength and temperature on the absorptivity and refractivity of material or for example for a sphere in baked bed?
Thanks
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Farnoush Salehtash Thank you. are those experimental methods?
My work is just theoretical research.
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For a 3D single phase turbulent Air flow inside a partially filled channel with porous material, what kind of interface treatment does ANSYS Fluent use for the interface between a porous and a fluid zone by default?
I know there are different interface conditions such as The Ene, Levy and Sanchez-Palencia interface, The Beavers-Joseph interface, but i want to know which interface conditions does ANSYS Fluent use.
For the porous zone Forchheimer extended Darcy’s equation and the thermal equilibrium model have been employed and the flow has been considered as laminar flow, but for the fluid cell zone the flow is turbulent and RNG k-Epsilon turbulence modeling has been utilized.
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Yeah, of course.
No one answered this question here, so i asked this question on CFD-Online's forum. A user named LuckyTran gave me this answer:
"I don't think there is any special interface treatment.
When you select the laminar zone option, Fluent sets the turbulent production in that zone to zero. The variables (k, epsilon, etc.) are still transported through the laminar zone.
There is another option (accessed using TUI commands) that allows you to also set the turbulent viscosity to zero in the laminar zone. But again, they are simply transported.
The pressure drop due to the porous media is handled by adding an extra volumetric momentum sink. If you need a reference, refer to the user manual section on Porous Media Conditions (see 7.2.1-3).
There is only one momentum equation. Refer to my previous post for why there is only one momentum equation when you use a laminar zone option. Interface treatment is needed in general when you actually have two separate sets of governing equations. But that is not the case."
(the link for this discussion on CFD-Online's forum:
I wrote my understanding from this statements for the reviewer, fortunately, he/she accepted it and here is our published paper:
Best regards.
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Dear Sirs! I need your help. I will have to work with PIM-1 polymer. In order to plan my experiment properly, I am curious in which types of solvents the PIM-1 is soluble except DCM?
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Hello everyone,
Hlib Repich you can use THF or chloroform as a solvent.
Regards
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I would like to predict Stiffness of composite porous material by understanding the stiffness of each particles .To do so, Is there any methods or software?
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@ Pascale Royer
I will try it as well, Thank you
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I'm currently doing simulations related with contact against porous materials (Tissues) in ABAQUS. As long as I use Pore Pressure=0 as Boundary Condition everything works fine and I'm able to obtain results. The issue is that in the contact area it will be fluid flow out of the material(exudation) due to the compression imposed. The fluid flow is in both contacting zones wich violates the continuity equation.
I've worked with the FLOW subroutine in order to control the boundary conditions in the contact area, and I also have tried the *Contact permeability keyword. I even tried to impose Pore Pressure=0 as an INITIAL boundary conditions.
I have also altered the parameters used to control the solutions (As the maximum number of cutbaks) .
I've read in many places in the ABAQUS MANUAL that by default ABAQUS imposed a sealed boundary condition. I guess this might be true for free contact surfaces but in my case it the program won't run if this BC are not imposed.
Nothing of what I've tried works, the program stops without calculating the very first time increment in all previous cases. Only if I forced the Pore pressure = 0 during the whole simulation, the problem works.
Any advice?
Thanks!
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Hi Marcel,
I have the same problem. In my model, I have two porous surfaces and I want to have fluid pressure to be defined at the contact regions based on the contact pressure.
So far no progress.
If you have found a solution please post it here