Materials - Science topic

I need to do TEM analysis for my Polyaniline emeraldine salt form. May I know which solvent is appropriate for preparing TEM sample?

I have deacetylated chitosan using 50% w/w NaOH for 6 hours. But still it doesn't dissolve completely. Should I repeat the deacetylation step?

Thank you for your guidance.

Dear Researchers,

Let’s share and discuss the best books that you have enjoyed recently in the field of Materials science and engineering.

Please let us know your opinion about this topic.

Best Regards,

Hossein Homayoun

It is well known that the value accounting for the average of all grain orientations in a polycrystal ("Taylor-factor") must be bounded between the Sachs (=2.24, assuming grains as indepentent of their neighbors) and the Taylor (=3.06, assuming all grains have to be able to undergo all possible deformations, i.e. 5 indepentent slip systems should be available per grain) solutions.

However, I sometimes see authors calculating shear stress-shear strain curves from macroscopic stress-strain curves using a value of sqrt(3) [1,2]. Taking the inverse 1/sqrt(3) leads to a value of around 0.57 as an "average Schmid factor", which is obviously higher than the theoretical bound of 0.5 on the Schmid factor.

Am I not getting something here or what are these authors referring to?

Thank you very much in advance!

Niklas

[1] On page 4: Li, S., Wu, X., Liu, R., and Zhang, Z., "Full-Range Fatigue Life Prediction of Metallic Materials Using Tanaka-Mura-Wu Model," SAE Int. J. Mater. Manf. 15(2):133-153, 2022

[2] Implied in figures 15, 16: Vayssette, Bastien; Saintier, Nicolas; Brugger, Charles; El May, Mohamed; Pessard, Etienne (2019): Numerical modelling of surface roughness effect on the fatigue behavior of Ti-6Al-4V obtained by additive manufacturing. In: International Journal of Fatigue 123, S. 180–195.

Hello, researchers. I hope you're all well. How can we know the type of semiconductor from the band structure (N type or P type)?

Thank you in advance.

The construction industry is a major contributor to global carbon emissions and environmental degradation. In recent years, there has been a growing interest in adopting sustainable practices in the built environment. Based on recent research studies, what are some of the most promising sustainable practices being implemented in the construction industry?

Like to know If I take without doing sample preparation Shall I get clearly images or not? Where I can do sample preparation in Tamil Nadu for taking TEM images with EDX?

I intend to perform mechanical tensile test for my polymer nanocomposites. Does there exists any ASTM standard to follow? Can I also know the dimensions of the specimen to be produced? Lastly, I intend to create a mould for the dog-bone shape. Can we get files online to create the dog-bone mould using 3D printer?

I am preparing chitosan film by casting chitosan solution into petri dish and let it air dry. I am using NaOH to peel off the dried film but it breaks the film. I have used different molar strengths of NaOH 0.01 to 0.1 M. But film breaks down.

I want to build a thin film of BCC iron

AssalamoAlaikum Hello Everyone hope you are doing well.

Yesterday I received an email from my supervisor in which he mentioned that to make a new proposal on the Topic of CO2 storage/capture as impurity by using GO (graphene oxide). I haven't worked on it. Could you suggest me some articles that are related to the topic and helpful to understand the topic. Actually I have to submit it in next 5 days so please if you have some information please guide me on this topic.

I am highly thankful to all of you for your time and suggestions (in advance)

I am using mixing models to calculate effective parameters (such as permittivity or permeability) of mixtures, i.e. inclusions with a given volume fraction in a host medium. There are several mixing formulas that can provide values of the effective parameter of the mixture, such as Maxwell-Garnett or Bruggeman.

Explanations can be found here :http://en.wikipedia.org/wiki/Effective_medium_approximations

Bruggeman's model treats the host medium and the inclusion similarly, and it can handle any number of different inclusions. But, there is a limitation due to the mathematical formulation.

Suppose the simple case of only one inclusion in a host medium, the equation used to find the effective parameter of the mixture is a second order polynomial. If the discriminant is negative (which sometimes happens) then the solution is complex. But this may be non physical depending on the application case (conductivity calculation, permittivity is neither the inclusion nor the host have losses, etc) where we know that a real value is requested.

For a higher number of inclusions, this may happen more often.

So, what is the solution in this case ? How to use Buggeman's model to get a real value for the effective parameter in the case the equation's solutions are complex ?

This is a discussion that I wish to go on and remain helpful for all the Drone researchers, manufacturers, designers, operators and users and sort of a buyers guide.

This question pertains to any type of material that one finds good to be used for various different kinds of practical applications. This is understandable that will applications, materials used will be different. Also, Long Range/Short Range and High Altitude/Low Altitude applications are a considerable parameters.

Few materials and applications are mentioned here. However, we are not limited to that.

Your input in the right material for the right application will be well appreciated.

Thank You for your contribution.

Dear Researchers,

I am searching for the material properties of EPO (Expanded Polyolefin) Foam to use it in the manufacturing of Fixed Wing Unmanned Aerial Aircrafts.

Requesting for your help with links and documents.

Thank You

Currently, the acceptance rate of MDPI Materials is about 65%. Normally, this rate is 20-30% for other journals. Is MDPI Materials publishing so many papers for money and compromising on the quality of work?

Thank you

I have jaw milled an aluminosilicate glass and omitted ferrite impurities via HCl. After ball milling with either metal cup and balls or stabilized zirconia balls with ABS cup, there are lots of impurities that I can not omit completely. I have tried both ball milling and wet milling and neither of them worked. Is there any other way to mill the glass powder to under 1 micrometer without this much of impurities?

Hi all,

I am doing a comparative study on the design of mats used in the microwave ovens and other general thermal applications. This involves the iterations in the design and the materials grades.

I have selected few designs from the available sources. The design involves the pattern of the ribs that helps in heat dissipation.

I am struggling to get the material properties for the food grade silicone or BPA free silicone. The properties helps us to conduct the thermal analysis for the mat.

It will be highly helpful if you can help me in getting the properties of the food grade silicone or BPA free silicone.

Thanks,

Prabhu

We have been synthesizing copper nanoparticles via chemical reduction method and using different capping agents to increase the stability of the copper nanoparticles as with the passage of time the color and oxidation state of copper nanoparticles vary.

We have so far tried immobilizing copper nanoparticles onto sepiolite, used capping agents like glycerol, tween80, CTAB and PVP. And different reducing agents including NaOH, glucose, ammonia, hydrazine and NaBH4 as well as ascorbic acid.

The synthesized nanoparticles attain brick red color and then turn black. We want to maintain the brick red color.

I will be grateful for your kind responses and guidance.

Hello,

One of my colleagues is working with piezoelectric components and couldn't find the shock response spectrum for various piezoelectric components. Can anyone please share your idea to deal with the calculation process of shock response spectrum (srs) of piezoelectric components? However, any informative links that contain useful resources or details will be very helpful.

Thank you for your time and guidance.

Best wishes,

Any provided material would be helpful.

If I were to make a half dome as an umbrella to protect a city from rain and sun how would I proceed. Are there special materials or do you have an idea on how to make this? What do you say about an energy shield ?

I have prepared magnesium green compacts from powders of different particle sizes. I observed that the green strength of compacts produced from fine powder was very low. Green compact splitted in two parts in the vertical plane during removal of green compact from the powder compaction dies. I repeated the experiment so many times and observed the same behavior. What can be the possible reason? Please explain.

Hello all,

I´m currently working for a medical device company. We are trying to understand the buckling effect during an insertion force test.

We use a flexible PVC extrusion with these properties:

Hardness: 95 (ASTM D-2240)

Specific gravity: 1.73 (ASTM D-792)

Tensile strength psi: 3400 (ASTM D-638)

Elongation%: 250 (ASTM D-638)

100% Modulus psi: 2860 (ASTM D-638)

This extrusion is inserted into another medical device and the force required to insert the extrusion must be below 4 lbf. However, it is noted that during insertion procedure the extrusion buckles, losing force and failing test. The extrusion is inserted using a fixture to guarantee that 4lbf are being applied, there are some cases where the readings of the force tester are below 4lbf but the extrusion get stuck and didn't pass all the way thru the medical device not reaching the desired end position. Our guess is that the column force is lost as result of buckling.

Extrusion length is about 10 inches, OD is about .077” and ID is .035”, this isn’t a solid extrusion. For this case, we would like to know much force (lbf) can be applied to the extrusion before buckling. Seems like we might use Euler formula, but it is unclear to me how to use the formula adding the factor that this isn’t a solid column, I assume wall thickness may be considered.

I appreciate any help to solve this doubt.

Thanks!

Hi,

A part of my research project is to obtain the strain distribution of a certain geometry that has one flexure. I define flexures as localized thinness that occurs in a constant thickness geometry (CAD picture attached). For my case, I am looking at a flat beam and a hollow cylinder with one flexure that is 5 cm wide and 1 mm thick, and there is a smooth transition from 2mm thick to 1 mm thickness. I am using ANSYS mechanical (static structural simulation) to get the strain distribution. I have also attached the plots that I got for both of the cases. My question is, for a flat beam, there is a clear rise to a higher strain value where flexure is placed, however for the cylinder case, there is a dip first, and then strain rises and then flattens out and then rises again, creating this "Batman ear" looking shape. I do not know why it happens. So I was wondering if anyone here has any idea or possible explanation. The geometry is set up the same: one end is fixed, and a point load is applied to the free end. The material for both of the case is ABS plastic. Thanks, in advance.

As the title says, I am trying to learn more about fracture analysis and how cracks propagate through brittle materials. Does anyone have any good recommendations on books or other learning material?

Thanks in advance.

I have several confusions about the Hall and quantum Hall effect:

1. does Hall/QHE depend on the length and width of the sample?

2. Why integer quantum Hall effect is called one electron phenomenon? there are many electrons occupying in single landau level then why a single electron?

3. Can SDH oscillation be seen in 3D materials?

4. suppose if there is one edge channel and the corresponding resistance is h/e^2 then why different values such as h/3e^2, h/4e^2, h/5e^2 are measured across contacts? how contact leads change the exact quantization value and how it can be calculated depending on a number of leads?

5. how can we differentiate that observed edge conductance does not have any bulk contribution?

hello! RP0！ I working with materials of tire . now , I meet a question.HOW TO IMPROVE DRY GRIP OF TYRE , JUST CHANGE THE MATERIALS OF TREAD COMPOUND?

With the increasing demand, the consumption of metallic materials is increasing. But the primary sources of these materials (ores) are limited. So, there is an urgent need for an efficient recycling technique to meet the increasing demand. There are mainly two techniques, powder metallurgy and casting, used for recycling metallic materials. Which is the better technique, powder metallurgy or casting?

Hi everyone, does someone know the work principles that VASP(The Vienna Ab initio simulation package) calculate elastic constant? I have checked many literature and they applied a matrix to unit cell, but I don't know if they are used by current version VASP(5.3.3). When I check OUTCAR, I can only find the elastic constants, but I cannot find where is the process, i.e, the matrix applied and the energy of strained lattice. Can someone tell me how to find those data, or introduce some literature about this?

I am applying top gate voltage using Al2O3 (100nm) dielectric. I would like to calculate effective elecrtic field applied using this top gate. I can apply top gate voltage of 1V (say). how much effective electric field can be obtained by 1V top gate.

Please help me

Hello, everyone,

I'm a little confused about valence band structure of Aluminum nitride (AlN). It is known that the crystal-field split energy in AlN is negative, so there are a lot of papers saying that the crystal-field split-off hole band is the topmost.

On the other hand, according to the k.p method (for example, or ) valence band energies at k=0 can be expressed as shown in the picture below (where Δ₁ is the crystal-field splitting).

For Δ₁>0 (like in GaN or InN), E₁>E₂>E₃ and the bands are usually reffered as HH, LH and CH, respectively, so the topmost band is the heavy-hole band.

For any values of Δ₁ and Δ_2, E₂ is always larger than E₃, so in the case of AlN E₂>E₁>E₃ which should mean that the topmost valence band is the light-hole band. Am I missing something obvious?

Another quick question is about an appropriate interpolation scheme for hole effective masses of ternary alloys. Should we use linearly interpolated Luttinger-like parameters A₁...A₄ for a certain composition to calculate the effective masses (including strain effect if needed) or should we calculate effective masses for the binaries from their parameters A₁...A₄ first and then interpolate between the obtained effective masses?

Hi I want to know more about how are new cities implementing biophilic design to their buildings and how much this is growing. Also how important is the LEED certificate becoming for this implementation.

Conduction electron density will be different in anatase and rutile structure of TiO2.

Upon equilibrating an Ice Ih structure at 250K and using write_data command for obtaining the end structure post-equilibration, I found that it does not contain the required bond information that was present in the initial geometry file.

Also, if the previous bond info from the initial geometry file is copied over to this new post-equilibrated data file, the bonds look incorrect on visualization and LAMMPS gives an error stating "Inconsistent image flags" and "bond/angle/dihedral extent > half of periodic box length"

Does anyone know how to write or extract the bond info post-equilibration successfully in LAMMPS? Attached are the initial (1hx20.lmp) and equilibrated (data.equibicev2) files pertaining to the problem.

Any insight is appreciated.

By definition, I know Lateral Strain divided by Longitudinal Strain but how to determine this by using Universal Testing Machine or any other method?

what is the procedure to find Poisson's Ratio?

My experiment demand x-ray CMT imaging. I need to place my samples over a substrate that should be x-transparent. Can anyone please any suitable materials (rather than foam) that is x-ray transparent?

Thank you in anticipation.

What is the mechanism and method of making the steel fibers used in reinforcing concrete and what are the residues or wastes or losses caused from the manufacturing stage ?

Are there detailed industry instructions that can be obtained ?

Absorption vs Wavelength Plot w.r.to Temperature.

Dear colleagues,

I am a researcher working with bovine hydroxyapatite. I want to reduce the percentage of carbonate on the sample. Is there any suggested techniques for this? I am measured the carbonate from EDX (SEM-EDX). Thank you

Thank you.

Please suggest what are different types of polymorphic transformations and best available literature decoding the same. For example, I am not clear if:

1. Different polytypes of SiC are due to reconstructive/ displacive or any other transformation?

2. Is existence of C as diamond or graphite due to order-disorder transformation?

3. Is the energetic material like CL-20 having 4-5 polymorphs due to displacive transformation?

Please discuss with examples

Hello everyone. Given microstructure image belongs to a 12% ledeburitic cold work tool steel (annealed and tempered). The sample was etched with picral (100 mL ethanol and 4 g picric acid). I tried to reveal retained austenite structure. Because I've limited knowledge in steel metallurgy/characterization, I need some help here. I know the white phases are carbides, which precipitate through thermomechanical forming. Any retained austenite can be observed? What would be black phases between grain boundries? Any answers will be appreciated about clarifying this microstructure.

I have created an Ice 1h crystalline structure and an Aluminium substrate structure and equilibrated both at 250K. Now I need to bring them together in a way that an adhesive bond is created. Reading the literature I have found that this can be achieved by an energy minimization process to bring the structure in contact and thereby inducing artificial stress at the interface that can then be relaxed and a nucleation process can be started; but I don't grasp how this is done in LAMMPS.

Any insight is appreciated.

I am looking for a scientific explanation for the anomalous values of Avrami exponents. Regrading the literature, the typical values of Avrami exponent have to be between 1 and 4. Different Avrami values demonstrate the different mechanisms of crystallization (Phase Transformation), including nucleation rate, growth rate, and dimensionality of the growth. Meanwhile, we obtained some anomalous values of Avrami exponents around 5, we appreciate any contribution in finding meaningful explanations.

In the case of Ti-alloys, it is confirmed that α stabilizer increases the c/a ratio. What is the mechanism of correlation of the c/a ratio with the unit cell? It is true if increases c/a ratio in HCP structure will linearly decrease unit-cell? or vice versa? What is the mechanism to connect these phenomena?

Generally we add spin-orbit interaction as a perturbation term in the system. which system has this spin-orbit term naturally in its hamiltonian.

In an alloy containing two different elements different in diffusion coefficient.

At high temperature, they diffuse or oscillate at different rates. Due to different oscillation rates, solute atoms possess compression force on neighboring solvent atoms.

May anyone give me a brief about this force?

I am trying to select suitable element type (Solid or Shell) for impact analysis. I have tried with both solid and shell elements. The results are same for both element types up to certain impact velocity, later there is a considerable difference in the results obtained using solid element and shell element. So I want to validate with the analytical model and select the element type which is close to the results obtained using analytical models.

Any other suggestions to select suitable element?

Hi everyone,

I wanna know about creating the Graphene model in CST.

In: Macros -> Materials -> Create Graphene Material for Optical Applications.

What is the exact formula that is used in this option?

Is it the Kubo formula? I compared this with the Kubo formula according to the attached files but they are not the same!

Maybe this attached formula is an approximation. So what is the exact one for the Kubo formula used in CST?

I would be grateful if you can help me with this regard.

Is it possible to compare the Theoretical maximum adsorption capacity (qm of Langmuir) of my sample to other materials when the (R2 of Langmuir is about 0.82) and the (R2 of Freundlich model about 0.98)

I have to dilute it, is butyl acetate suitable?

An interstitial atom (such as H, N, O) sitting not on their regular place, but between other atoms in the metals structure.

How to detect where is their location on that structure (in crystallographic viewpoints) with instrument analysis rather than assumed.

thanks a lot

Any close value will also work.

I need references articles that explain the drawings for the following materials, which illustrate the diagram between DR UV-Vis spectrums of the following materials blank sample as expressed in Kubleka-Munk function versus

the measured wavelength and the materials are ZnO, CuO, Fe2O3, and Co3O4.

I request the professionals in this to please help me in my project which i am doing in my final year. I'd be very grateful even if its just a bunch of research papers or websites that your sharing.

thank you.

What according to you should be researched/accessed with respect to WC based solid lubricant tools? What is your view with respect to future research in this area? (For e.g. Tribological study etc..)

Thanks in advance..

A kind of surface roughness is produced by the application of laser energy density at high laser power (> 140W) which looks like an open porous structure. This kind of structure is not observed at lower laser power.

Is it produced due to oxidation of the layer? Or could it be a sign of instability at high laser power?

The main (and generalistic) advantages and disadvantages of each type of nanosystem have been widely pointed out in literature. However, the advantages and disadvantages stated are too broad and sometimes overlap. Of course, it can depend on several factors: the targeted tissues; the loaded compounds; the type of administration; the final formulation; industrial scalability; among others. This way, this question aims at opening a debate to untangle and explore further the potentialities of each nanosystem and, more specifically, the (1) differential and (2) more specific applicabilities of each one towards the right final choice for the preconized biomedical application. Personal experiences and opinions are deeply welcomed!

I want to convert the Young's modulus and Poisson ratio of an orthotropic material given in Cartesian coordinates into cylindrical coordinates. Please suggest me the way or provide me the link or document where I can get these things. Thanks in advance

At the moment, only the lazy one doesn't investigate high-entropy materials. But what is that?

I need to draw a comparison between the two for my study of their frictional factors. Motivation is towards its industrial applications mainly pertaining to fluid dynamics. Any leads would be really appreciated.

Thank you!

I want to know about the type of polymers in PCBs.

Im trying to model the failure of polycarbonate using the Johnson-cook model for ductile metals in Abaqus, I have found literature in which the parameters for the constitutive equation were given, but I havent found any resource with values for the fracture model, does anyone have any knowledge or could point me in the right direction?

Cheers!

Alex

I am searching for various materials related to energy absorbing applications. These material should sustain high shock load like a near field blast scenario. As far I know, there are some materials like, FRPs, Metal Foams, concrete structure, Honeycomb structures of metals and nonmetals, which can absorb the sudden shock loads.

Kindly suggest some advanced energy absorbing materials which could sustain very high shock load and suppress the shock waves.

3D printing in many settings is indicated to be a 'hobby'. However, if one envisions how 3D printing can contribute to re-shaping our day to day lives, one possibility is to make use of materials for common uses or that contribute to circular use cycles. Organic materials are available in many forms around our collective living environments. Therefore, understanding what materials are available and common products that are used could help to identify paths of research that could utilize 3D printing on larger scales and more common settings.

I am looking for literature on high temperature solders, also containing Pb. Any suggestions will be highly appreciated.

If global warming cannot be resolved by controlling/minimising gas emissions, then extraordinary measures may be the only viable options, one of such ideas is placing a solar shield between the sun and earth at the L1 lagrangian point to obtain a reduction in solar insolation . It may sound crazy, more like science fiction to know that a disk of 2000km in diameter would be necessary to reduce solar radiation reaching earth by 1.7%. I wonder about the sort of stresses that would be experienced by such an enormous body. Also, what sort of materials' properties would be required to withstand the conditions at L1, for example solar radiation, other rays. While it is possible to calculate the disk's orbital velocity around the sun, its angular velocity (around its axis) is difficult to calculate. I would be grateful if those with relevant experience could share their thoughts about how such calculations could be achieved.

Dear all :

May anyone share with me a Graph showing the curves for Temperature vs Thermal Conductivity, and Temperature vs. Electrical Conductivity/Seebeck Coefficient (in the same Graph) for distinct type of materials: (semiconductors, semiconductor alloys, metals, semimetals, etc.) showing the points in the range up to 1000°C ?

This is for use in Thermoelectric materials.

If someone can send it to me I'll appreciate it a lot

Thanks !

Some good models have been proposed for compression (e.g. Mander et al (1989), Scott et al (1982)). But which model to choose for tension?

Trying to find out how the frequency affects the dielectric constant of a material in order to find a substitute. Thnk you in advance for any help with this.

Because of different deformation coefficients of materials in perovskite devices, we have some troubles to get good cross-section SEM images when trying to cut the devices. How do you usually cut the solar cell devices?

Thank you!