Chemistry - Science topic

Interesting

Dear Ammar Bader,

It is a very useful idea. There are already several platforms for international cooperation. either sectoral or general, regional or global, e.g.:

https://covid-19-response.org/

https://ec.europa.eu/info/funding-tenders/opportunities/portal/screen/covid-19

https://www.clustercollaboration.eu/coronavirus

https://iite.unesco.org/announcements/launch-of-the-new-online-platform-initiative-on-combating-covid-19-together-we-are-on-the-move/

https://www.itu.int/en/ITU-D/Regulatory-Market/Pages/REG4COVID.aspx

All the best,

Monica

The novel coronavirus detected in China in 2019 is closely related genetically to the SARS-CoV-1 virus.

Any of the available data can be obtained free of charge via

It may be due to aggregation, use stabilizing agents to reduce aggregation.

One can, of course, already pay the fees! They want your money!!!

MestReNova , ChemDraw professional for synthesis

Gold, Moe, Glide for computetional docking

Pymole

I see some very good answers - we do the estimation by measuring the change in thermal conductivity of the space. The measurement can be more meaningful if you know the composition of the mineral deposit. The thermal conductivity of common water system scales is known. If the accumulation is, in fact, deposited, not grown in place - then the thermal conductivity model would be more relevant within repeated accumulation/settling of solids in that location.

Thermal conductivity is an accurate means of measuring the relative thickness but the results are more material with repeated measures or an accurate knowledge of the physical and chemical composition of the matter of interest.

You have answered your own question. Proper chromatography methods require detection methods which are applicable to the samples under analysis. You may want to review the types of instruments, detectors, columns and materials available at your school before deciding on a final approach. Have someone in the school's analytical instrument lab assist you.

For HPLC samples with weak or no chromaphore, you will need to use a detector that does not rely on wavelength based light absorbance such as an RID, ELSD, CAD or MS, to name a few. Put a little time into researching this basic question so you will better understand the uses and limitations of these methods and detectors. I often suggest my students start with a keyword search on the web (GOOGLE or BING) to find examples and articles to review. This is one of the best ways to learn. Once you have familiarized yourself with the basics, be sure to ask your teacher for help in setting up and running some example methods.

BTW: You may also be able to derivatize some of your samples and use GC/FID or GC/MSD as an alternative to HPLC (only if the samples are appropriate).

There are few standard test methods to do this:

Bromine number (total value of olefins)

PIONA (group type separation, but it is possible to match some individuals)

DHA - individuals.

You can combine also DHA with GC-MS.

Regards

GB

Hello, you see, it depends on your goal. You have to plan. How do you plan? You plan by looking into the time frame of your goal. If you are doing your dissertation (PhD. or Masters) no time to start reading from scratch, you would not just meet the deadline. In that case you just need to do extensive literature review using reputable papers like ieee or science direct etc, note some points and go to the work you have interest that you can handle and finish your work first. Publishing and growing do not always come by hard work mainly, it comes by planing by being smart in the right way. If you are on your post doc in some school in China where they pay you, you are to return the money back if you don't finish within the time frame. In most cases doing extensive literature review should be the first things not studying deeply chemistry or physics first....just like Isaac Lare Animasaun said. When there is time and you want to go deep then, after finishing your goal then, you can start study chemistry or physics deeply if it will make you grow. It's just more or less like your life academic management. Have academic plan for a year, two, or even 5 or next ten years. Do what will add to you.

I read that after leaching of oxidized zinc concentrates with sulfuric acid, the resulting solution is purified from harmful impurities like iron, copper, cobalt, nickel. And with a weakly acidic medium, pH = 5.2–5.3 iron ions are practically precipitated by the formation of hydroxides.

Dear Dr Gilson

I am ready to help if I could and be grateful to do something due to make progress!

I think many valuable media and journals could be useful for you such as:

https://www.nature.com/subjects/environmental-chemistry

https://www.wiley.com/en-us/Environmental+Chemistry+at+a+Glance-p-9781405135320

https://www.springer.com/journal/10311

Hydazine hydrate solution in water is basic (pH=11) but the solution of Hydrazinesulfate in water is acidic (pH = 3). So to get the hydrazine hydrate from hydrazine sulfate , the pH of the hydrazine sulfate solution has to be tuned to pH= 11.

Here the procedure:

Dissolve the Hydrazinesulfate in water ( 1 g in 30 ml), check the pH (then add Ambersep 900 hydroxide from resin (or any other OH from resins) and adjust its pH to 11. Filter the solution to obtain Hydrazine hydrate.

I have used this procedure recently, it works very well.

I have been receiving emails recently from L.Smith M.D. All his emails are very pushy. Thanks to all of you for discussing it here. He is in my spam list now.

Mostly adipic acid, manufactured from hexane, and also 1,6 Hexane Diamine, also made from hexane. Or Caprolactam made from hexane.

Hi Mohammed,

I don't think that anyone will be able to give a satisfying answer, since nobody knows what exactly you want to do and which infrastructure your university can offer:

There are multiple extraction methods, but you can probably use relatively simple instruments. Depending on your extraction procedure, you might need a rotavapor or just remove the solvent with a flow of inert gas. Once you have an extract (or fractions), you want to screen it for some biological activities. You might want to check for antibacterial activity, which is relatively easy. You might want to check for the effect on different mammalian cell cultures (cell culture lab and microscopy required) or you might want to test for some activities on animal models.

Of course, it makes a huge difference if you can use an autoclave at the institute, some cell culture lab from a different group, maybe a mass spec facility or if you have to set everything up on your own.

Furthermore, think of groups or services that could help you. For example, you will not set up a cell culture lab, if you want to check for cytotoxic effects of some substances - you could rather have a collaboration partner or company do it for you.

I think you should really narrow down what you want to do and which instruments would be absolutely required for this. Check, which instruments you could use at your institute, which things could be done by collaboration partners and which instruments you would have to purchase. Then, you could think about "nice to have"-equipment...

Best regards,

Sebastian

see below link

https://www.techrepublic.com/blog/five-apps/five-tips-for-extending-lithium-ion-battery-life/

It is very important choosing suitable ion exchanger which is has weak ion weaker than the ion you want to capture.

It looks like neither the journal nor EndNote provide a style file, thus you will have to edit an existing style (perhaps ACS). If you have EndNote on your computer (not the plug-in but the stand alone program), go to Edit/Output Style/Edit "ACS"/Bibliography/Templates. Edit the journal article template, then save the edited style with a new name. When you reopen Word, you should see it when you "Select another style".

Dont worry. Dr Kafferlein. We are all here for discussion. That's no wrong or right answers. Thank you so much for your contribution.

Please observe what happens when CH₂CL₂ , taken in a separating funnel, is shaken with a little bit of water and then allow the mixture to get separated in to two layers.

Collect the organic layer, and observe the layer keenly and add anhydrous Mg(SO4)₂ to the organic layer. The layer on becoming dry, should turn into a transparent liquid after becoming dry.

Now, the following would be my comments.

(a) Absorbed moisture can impart turbidity to organic solvents. This is specially so with low-boiling liquids like CH2CL2 and diethyl ether.

(b) Anhydrous solvents normally have a great tendency towards absorbing moisture, when kept exposed to a moist environment.

(c) Please do keep in mind that chlorinated hydrocarbons are normally avoided due to their toxicity.

The foods we eat, the air we breathe, cleaning chemicals, our emotions and literally every object that we can see or touch, Love, jealousy, infatuation and all share in chemistry. For all living things to function and survived their bodies perform various chemical processes.

You can also find more in this link:

Daniel Jackson yes, you are right, you need made serial dilutions from the primary solution. I recomend you this video to understand the method.

https://www.youtube.com/watch?v=MCrNjHcfcpY

Regards.

Hello Mr. Ulrich Deiters

My solvent is water.

I hope you feel well today. I will write what I understand from your equation. In really adsorption presence is separation method or transfer containment from liquid or gas phase to the solid phase. Therefore, there are products waste as solid can control it for disposal or reuse. All treatment processes need an energy source for work but adsorption does not want that. The low cost of operation and the initial cost of adsorption is the advantage. On the other hand, we use the adsorption process for removal of the low initial concentration of the heavy metal that can't be removed from water by precipitation. Today, the researcher tries to find now mater that has high adsorption capacity at the same time made this material from waste ( the name of adsorbent is super-adsorbent ) such as metal-organic network , nanoparticle, polymer, and hydrogel.

you should be told us about the nature of your sample, and nature of the analyzer instrument to solve this problem

You might be able to couple the rhodamine carboxyl to an alginate hydroxyl with a water soluble diimide coupling reagent.

Or use a different dye....

You may not want to use the following advice if you are weighing hazardous substances: don't wear gloves. They are a big source of static. Check with the lab head whether this is permissible if you want to try it. Wash your hands afterwards.

Otherwise, minimize static by avoiding a lot of motion of the solid in its container. In other words, avoid shaking or tapping the container. Use metal spatulas, not plastic ones. If you are not weighing the solid directly into the final container, use glassine weighing paper rather than a weighing boat. Use the smallest feasible piece of weighing paper, not necessarily a whole one.

Thank you gentlemen for your assistance, really appreciate it.

Hi Ryan,

I think that B is the correct answer. Usually Mixing solvents with statement 1:1 means equivolume mixing of components, (1+1=2volumes diluted finally x2) which finally yields halved concentrations of constituents. This should be premixed if used as Hplc mobile phase and degased, and pumped through special pH basic resistant column matrix.

The hottest topics right now in organic chemistry research are Green Synthesis,

Chiral Engineering, Nanomaterials and Biotechnology

Spectrometric identification of organic compounds I Robert M Silverstain

Yes, if electron withdrawing groups are prsent in near or conjugation to phosphrus, then n then only chance for more labile oxidation. but any phosphites are highly undergoes to oxidation so inert atmosphere is needed.

thank you

J. C. Tarafdar thank you. Can you please suggest me any article?

Hydrophobic and in layman's terms slippery!

Ender Araujo

I have experience with r-candy propellants, and its not very dangerous as other solid propellants (for example APCP). If you apply the basic safety procedures you will be very safe (lab coats, safety googles, masks etc). If you make the propellant by heating method, then you must be carefull with the burners, because when you put the propellant in the mold through casting method, its very important to ensure that the propellant will not fall on the burner by mistake. Because you have to make the propellant with students, I will recommend to you to mix well the KNO3 with sugar as raw materials and do not use the heating method.

Also, you have to consider that these propellants are not easy to ignite them, so be sure that you will ignite the propellant from far, using ignition wires, not with lighter.

If you want to increase the burning rate, you can decrease the KNO3 particle size or you can add a small quantity of Fe2O3 red iron oxide as catalyst. But if you do that, you have to keep in mind that it will be more dangerous.

It is very good to learn to your students the significance of safety.

Dear Dr. Haider Abdulkareem Al-Mashhdani,

in a previous question relating to this topic here in ResearchGate, Dr. @Angel Cuesta, gave the following, very clear, explanation.

The Tafel slope simply tells you how much you have to increase the overpotential to increase the reaction rate by a factor ten. This will be determined by the magnitude of the change in the activation energy for a given increase in overpotential (when you change your potential 1 V, the Gibbs energy of the process will change by 1 eV per electron transferred, but the activation energy will only change by a fraction of this, and this fraction determines the Tafel slope). In a reaction involving only one step with one electron transfer, the Tafel slope will be determined by the symmetry factor, which is usually 0.5 (corresponding to a Tafel slope of 120 mV). In a more complex reaction involving several steps and several electron transfers, the Tafel slope will be determined by the rate-determining step and by the number and nature (i.e., involving an electron transfer or not) of the preceding steps. So, essentially, from the Tafel slope you can deduce whether your rate-determining step involves an electron transfer or not, as well as the number of electrochemical (involving an electron transfer) and chemical (not involving an electron transfer) steps that precede it. If you propose a reaction mechanism, you can calculate what the corresponding Tafel slope should be and, if it does not coincide with the experimental one, the mechanism cannot be correct.

For more details, you can have also a look at the following notes:

-Tafel Plot and Evans Diagram

By Palm Sens

Available at: https://www.palmsenscorrosion.com/knowledgebase/tafel-plot-and-evans-diagram/

- Quantitative Corrosion Theory

By Gamry

Available at: https://www.gamry.com/Framework%20Help/HTML5%20-%20Tripane%20-%20Audience%20A/Content/DC/Introduction_to_DC_Corrosion/Quantitative%20Corrosion%20Theory.htm

Best regards, Pierluigi Traverso

Hi

How do i separate powder it contains sodium bicarbonate,tartaric acid and citric acid by HPLC or only organic acid ?

SiF4 gas will appear and take in consideration that SiF4 is toxic and corrosive. In moist air it fumes, whereby it is easily hydrolyzed to give H2SiF6 and SiO2. However, in my opinion the most toxic / hazardous substance in this system is certainly HF. Utmost care must be exercised when working with HF, especially if it is a concentrated solution (40%) or even anhydrous. It easily penetrates the skin and can lead to serious injuries

You're welcome. I just noted a typing error in my answer. 0.786 g AgNO3 is of course 4.63 mmole, not 6.63 mmole. It must be the same as the mmole amount of Ag.

Ashok - H2O2 is used to remove organic matter from sediments - not carbonates. If you are trying to remove carbonates, but wish to leave any clay minerals unaffected, you should use a buffered sodium acetate/acetic acid solution (pH 5.3). If you aren't concerned about the clay minerals, dilute HCl would be fine. E-mail me if you would like the method.

Saida, If you have a look at a Dieke diagram it'll be apparent to you that the energy states of La are well separated (gs and es) way above its bandgap so no emission line will fall in the visible region. And La doesn't have 4f electrons as the other lanthanide ions do. Also, other emissive lanthanide ions which are often used as emitters, have energy levels that are separated by energies falling in the visible range. However, due to the inner shell configuration of these 4f ions, it's very unlikely that you can directly excite a 4f-4f transition in these- so you'll see little-to-no emission intensity. However, if you have La in the material it can absorb the incident energy and efficiently transfer it to the emitting lanthanide ion in an indirect way. But this energy transfer is strong enough that it populates the emissive states of your lanthanide activator and you'll see the fluorescence occurring from them. That's why you see an increase in luminescence efficiency in the presence of La.

I agree with Neeraj K. Sethiaya

Just the the second method, you cant use methanol to isolate the alkaloids,

you most make two immesible layers , like chloroform and polar solvet,

Best regards for all

Souad Djellali Neeraj K. Sethiya Alok Nahata Souad Djellali Jack Silver

Working with C2-Ceramide it obviously had an effect on the treated cells in our publication ( ). Therefore, I think it is increasing solubility and subsequently effectivity of the compound. For the preparation of a C2-CER BSA mixture you can follow the instructions by ENZO. It worked well for me.

Best

Konstantin

I also recommend

Ellis, KJ et al. Methods in Enzymoloigy, Vol. 87.

and

Dawson, RMC et al. In: Data for Biochemical Research. Chapter 20.

Yes Mr.

Actually, when we try for the annealing of potassium niobate, we suffer from those cracks on the tube. The niobium gets reacted with Si and forms Niobium Silicate. Those cracks are at inner surface of the tube. And cracks get propagated and unfortunately that tube get damaged.

I agree with C.A. (Kees) Kan

I think Merga already shows the answer in her question. Todays students' attention need to be captured. Lab facilities are excellent in doing that, e.g. with a CS Phosphorus flame (Phosporus dissolved in CS on a paper, CS evaporates, paper catches flame) or more elaborate chemical reactions. Lacking such facilities takes more inventive approaches to capture their attention.

Dear Gabris Mahamid, Such a database aggregated and sorted at this stage is being developed. It has not been tested and therefore cannot be seen. The development is of large companies such as: Web of Science, Scopus, Google Scholar and Google Academia, Microsoft Academic, Semantic Scholar and others. There is only a partial finding at this stage of these data companies on specific topics in specific areas. Wishing you success in research. Emil Yankov

Study of diseases and the pharmacological potential and mode of action of drugs

Dear all, some journal use the experimental details in a separate file with a specific DOI. It is named 'Supplement file'. It is mentionned in the first page mother file. Generally it is free downloadable. My Regards

Thanks for your message Priya Dharshana.

I am looking for a sample not for a template.

Hi;

The electrosynthesis provides a better environment for the generation of reactive species by dissociation or bond forming processes. The reactive carbon species are used in various synthetic transformations, essentially C-C bond formations. Oxidation and reduction of functional groups are also important reactions in organic synthesis. A major advantage of electrosynthesis is the reduced formation of side products.

With my best regards

A magazine is definitely not the same as a Journal. Magazines normally carry popular articles, not original work. A Scientific Journal publishes original scientific work not published elsewhere. 'Letters' or 'Notes' are of shorter length. It may include a comment on an already published recent paper by the author or someone else. Normally, Editor takes decisions on 'Letters' and 'Notes'. Seldom are they are sent to reviewers.They get published quickly. A full length paper in a reputed Journal has to undergo peer review process and may take up to an year or so to get published.

Hello, same topic discussed here

Good Luck!

https://www.researchgate.net/post/Is_there_a_protocol_for_a_second_immunostaining_of_organotypic_hippocampal_slices

Jingjing Xue

There have been a lot of initiatives to include active learning exercises in both lecture and lab. Many have observed good results in information retention and elimination of misconceptions. I have observed some of these results firsthand, and active learning is something I think is quite valuable. Here are a few resources, but there's lots of info out there:

For curriculum, I have noticed a shift towards an "atoms first" approach, but I haven't seen anything conclusive on its effectiveness. My feeling is that it works well for some students, not for others (just like any approach). I have yet to see any good methods on stoichiometry excepting certain teachers who have a knack for explaining it well.

This article suggests focusing on training teachers and developing innovating learning material:

This blog suggests directing chemistry towards things people will actually use and encounter (cooking for example):

The American Chemical Society has a small guidebook on what should be explored:

(See also attached pdf)

I hope the resources will help you.

The lightest elements (mainly hydrogen and helium and in trace amounts lithium and beryllium) were formed about 100 seconds after Big Bang through the Big Bang nucleosynthesis (this process lasted up to 20 minutes after Big Bang).

After the formation of stars new elements, from helium to iron, are produced in stellar nucleosynthesis (thermonuclear fusion: CNO cycle, proton–proton chain reaction and triple-alpha process) during stellar evolution.

Elements higher than iron are produced in supernovae through the r-process and s-process.

A very good book about this and generally about properties of stellar interiors and the structure and evolution of stars is: "The Physics of Stars" A. C. Phillips.

About the nuclear physics of stars, you can see also a book of Christian Iliadis "Nuclear Physics of Stars".

i am work about antibacterial activity of material and synthesis of nanomaterial

H. Taube, who received Nobel prize in 1983, studied the rection of MnO2 with Cr2+ in 1964( Inorg, Chem. Vol.3 No.3 p967).

Store the stocks in the fridge, i.e. cool and dark, and they should last for months. What tends to happen is that they slowly concentrate due to evaporation. So use good containers. The more dilute solutions are more stable in acid. Even 1 mg/L is quite concentrated beside the solutions used to calibrate ICP-MS so it should be OK for a few days. Beyond that rely on testing for yourself.

Can you tell if it exploded (pressure build up) or imploded (sealed while warm and bottle was flawed)?

Only concentrated KOH is dangerous (Caustic soda). But solutions of 10 - 15 % (that is around 2 mol/l) are medically used for topical application.

I can find safety data for a KOH solution of 0.1 M at a Sigma-Aldrich site

https://www.sigmaaldrich.com/MSDS/MSDS/DisplayMSDSPage.do?country=NL&language=EN-generic&productNumber=417661&brand=SIGALD&PageToGoToURL=https%3A%2F%2Fwww.sigmaaldrich.com%2Fcatalog%2Fsearch%3Fterm%3DKOH*%26interface%3DAll%26N%3D0%2B8653199%26mode%3Dmode%2520matchpartialmax%26lang%3Den%26region%3DNL%26focus%3Dproduct

NO STATEMENT for special ventilation is given for 0.1 M KOH

But for 0.001 M, their could be no harm at all (except do not swallow ..). No need for special ventialtion or fume hood.

What about try acid digestion?. Normally people to determine the metals by ICP-MS using HCl:H2SO4: HClO4.

You can measure the stoichiometry of a sample using X-ray photoelectron spectroscopy, although XPS is normally very surface sensitive so there may be some difference between the measured st. and the bulk of the QD depending how small it is.

Chemdraw 3D, Automax 3D, Adobe illustrator, Material Studio, power point and so many others. It depends on your ability how to use and draw a complex molecular morphology and architecture.

Drotaverine is sparingly soluble in water. In DMF/PBS 1:5, the solubility is 0.16 mg/mL. See https://www.caymanchem.com/pdfs/20944.pdf

Dear Sammy,

Prof. A. Tikhonov already nicely summarised the most important issues concerning up-conversion. As far as phosphors are concerned, there are a couple of materials that can show rather efficient NIR to VIS up-conversion at moderate irradiation levels. These are: NaGdF4:Er,Yb; Gd2O2S:Er,Yb; BaY2F8:Er,Yb and YOCl:ErYb.

All of these materials make us of the mechanism of Sensitised Energy Transfer Up-conversion (S-ETU), while Yb3+ is the sensitiser and Er3+ the green or red emitter. Important is that the host material has solely low phonon energies, otherwise the process is easily quenched by electron-phonon coupling. Good luck!

Thomas

When we want to trap hydrogen fluoride on a filter in order to estimate its concentration in the atmosphere we use filters soaked with sodium carbonate. I think you could try to adapt this method to your issue. You can see an exmple of the use of this method here:

Christian Chavis Christian Chavis In pharmacy, a w% or more commonly w/w% is the number of parts by weight of the solute (or active ingredient) contained in a hundred parts by weight of the final preparation. so to get a 10% W/W solution you have to dissolve 0.5 gm of your solute (PCL) in 4.5 gm of the solvent (TFE, you can convert this to volume of TFE by dividing 4.5 by the density of TFE). I hope this is of use. Best wishes.

I have seen reasonable amount of PM2.5 over India from the WRF-Chem using the RADM2 MADE SORGAM. As you mention that changing chemistry to MOZCART also did not improve the model performance in your case, it is possible that your input emission has some issue. Pl check wrfchemi files how PM emission data is written there. If unresolved, you may send me a sample plot of PM2.5 emission and I can tell if these values look fine (and also correct units). All the best.

Hi Martin,

it is not easy to reply because of many options and variables.

By my knowledge, if the thickness is higer than some 0.2-0.3 mm and the substrate is not greatly flexible, then 100 - 500 nm thick SiOx based coatings obtained starting for example from HMDSO are a good solution. I tried in the past with multialyer coatings based on different SiOx design with satisfactory results in terms of barrier properties. Otherwise, if the substrate is greatly flexible the film risks to be fractured and lose its barrier properties. In such case polymeric coatings with lower barrier properties but higher flexibility should be more effective. Best regards, Simone

Hello Patrick,

'G09 does not print connectivity data in the out file. However, if you check your output file, you can find 'Distance Matrix'. Once you have done optimization, visualize the output and if you save gif file then you can get the connectivity data.

"

1/18=20,19=15,38=1,57=2/1,3;

2/9=110,12=2,17=6,18=5,40=1/2;

:

:

"

These are IOp options corresponding to the specified keywords. (for further details see: https://gaussian.com/iop/ )

Best regards,

KRISH

Simply use the combination of probe and bath sonication. You can synthesize 5 nm MoS2 quantum dots. You have to run your bath sonication continuously for atlest 24 hours without any break.

Ok but you want the concetration of the chemical species in the two different solutions to be the same?

Are you sure that your precipitate is Cu metal rather than Cu2O, which is also reddish in colour?

You could try ascorbic acid as reducing agent - I've used it to make CuCl (very easy method, much nicer than any other I've tried!). To get rid of excess ascorbic acid with less risk of oxidation than if you use water, use methanol: ascorbic acid is significantly soluble in methanol, much less soluble in ethanol.

hth!

Joel Kumlin The display is incorrect, the temperature was maintained at 60C using a thermometer. Thank for your feedback on mentioning that stirring rate also affects particle size, could you suggest me a suitable RPM which I am advised to maintain? (i was maintaining here 700 RPM)

Hello! There is a lot of resources available in the net regarding stable isotopes. I was able to download an old copy of Robert Michener's and Kate Lajtha's book (2nd.ed, 2007 Blackwell Publishing) on Stable Isotopes in Ecology and Environmental Science. It is quite informative and easy to understand.

It might interest you to know that stable isotopes are naturally occurring. So far, I have not encountered a study (maybe my search is limited) making use of stable isotopes for application other than as indicator for certain parameters. Regarding your question on whether these isotopes are more advantageous than conventional elements, it might really depend on what you want it used for.

Very interesting discussion.. thank you

Hi;

Please see this reference:

Modelling CO2 solubility in pure water and NaCl-type waters from 0 to 300 °C and from 1 to 300 bar: Application to the Utsira Formation at Sleipner.

My regards

To the best of my knowledge there are three companies with materials potentially suitable to alkaline AEMFCs.

1. FuMa-Tech was mentioned above - FAA-3 was an early standard in AEM fuel cells and I used it extensively. To the best of my knowledge it is QA-based but not styrenic backbone chemistry, and from first-hand experience the membranes are quite tough. I can't find the FC-grade in the store, but it's in the spec below; ionomer solution should be available in NMP even if I can't find it listed on the site either.

2. Dioxide Materials has materials available but I have much less first-hand experience and don't know the suitablility in fuel cell applications. They appear to have styrenic backbone chemistry and need to be treated right but they may be suitable to your needs. There is ionomer but the disclaimer is that it is designed for CO2 electrolysis so again I'm not sure about the compatibility.

3. With full disclosure I'm a co-founder and part of the company, Ionomr has alkaline-stable AEMs with a set designed for AEMFCs and ionomer compatible with low-boiling solvents for consistent electrodes.

4. While not a company, Prof. John Varcoe is an amazing person and his materials are well-known enough to comprise a research standard.

There are a handful of other companies mainly in the US at early stages but to the best of my knowledge this is it with regards to commercial availability for materials suitable for AEM fuel cells.

K672-100 Heme Colorimetric Assay Kit

Yes, it exist lots of other transition metal oxide exhibiting thermochromism. In case of VO2, it is a metal-insulator transition, which is widely studied.

You have similar mechanisms in cobaltite and nickelate perovskite (RENiO3 and RECoO3; with RE= La, Pr, Nd and Sm).

You can have a look on these paper:

doi.org/10.1016/0022-4596(91)90077-U

Lacorre and Torrance published a lot on this topic in 90s-00s.

The reason, in case of perovskite material, is due to the bandgap overlapping of the 2p O orbitals and 3d metal orbitals by changing the temperature. In ABO3 perovskite, you have BO6 octahedra (metal atom surrounded by oxygen octahedra cage). The angle B-O-B between two octahedra is responsible of the bandgap energy.

The transition has been described as the ZSA model (Zaanen, Allen, Sawatzky):

At low temperature, there is no overlapping, insulator behavior

At high temperature, lattice distortion and bandgap narrowing, that can go up to the overlapping of 2p O and 3d metal orbital: metallic behavior.

The angle between the B-O-B is directly dependent of the RE size (it is 180° for cubic and decrease as the RE size decrease).

Regards,

Emile HAYE

Dear Samiksha,

during winter months when the water column is oxic, Fe oxide reduction only occurs in the strongly reducing sediment column. Reduced Fe(II) diffuses to the sediment-water interface where it is immediately oxidized to Fe oxide. As a result, there is no buildup of dissolved Fe in the water column during winter. In early summer the lake becomes thermally stratified. As summer progresses, oxygen is consumed by biological processes and the bottom waters become anoxic. Reductive dissolution of Fe oxide continues to occur in the sediments. Fe(II) diffuses into the anoxic bottom water and is oxidized at the oxycline forming a peak in particulate Fe in the water column. Below the oxycline, where the water is strongly reducing, dissolved Fe(II) is stabilized and its concentration increases with time. In early winter, mixing processes re-oxygenate the entire water column and Fe(II) is rapidly oxidized and precipitated.

Here is a classic work on the subject by Mortimer: https://www.jstor.org/stable/2256395?origin=crossref&seq=1#page_scan_tab_contents

After creating an account (free), you can read the article for free.

With best regards,

Johannes

to my knowledge the product is unstable so it is difficult to measure thank you

I think the change (reduction) is not significant; it could be related to the device error. Besides, the samples with 0.3 and 0.5 do not seem to show saturation. Anyway, the change in retentivity is usually correlated to the crystallite size.

Thanks a lot Abdelkader

The list of contaminants of concern include materials that are oxidation mobile. Therefore, a reduction barrier in the saturated zone could be a suitable method to remove contaminants in-situ depending on knowing many more specifics about the site.

As the particle size decreases you can form thinner film by spin coating. Then it depends on the film thickness required. I assume the film thickness may be multiple particulate size to have full coverage and uniformity.

As grain size decreases you can control better the morphology and the thickness uniformity of the the deposited layer.

The nano scale helps you produce more thinner and and more homogeneous film.

This is a straight forward consequence of constructing the film from the grains.

Best wishes

@Andrea Snow, simply, begin classify them and use, for example, MS Excel or MS Access to organise their using.

Thanks all

Selection of Conductive Additives in Li-Ion Battery Cathodes