Chemistry - Science topic

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.

Dear Yasir Iqbal,

One of my favourite book is the encyclopedia of spectroscopy and spectrometry (John C. Lindon, George E. Tranter, David. W. Koppenaal ; Eds), 2010. I would also recommend some other books specialized in NMR and fluorescence.

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

Dear Ramin Javahershenas,

Actually, numerous publications are about photoredox catalysis or photocatalysis. More and more scientific research is carried out in organic electrochemistry and electrophotocatalysis.

Hydrophobic and in layman's terms slippery!

Decade means for example 1 mA to 10 mA, or 10 mA to 100 mA, in log scale -3 (0.001 A) to -2 (0.01 A), or -2 (0.01 A) to -1 (0.1 A).

So the Tafel slope of +/-120 mV/dec means that between 1 and 10 mA potential increase (+) or decrease (-) for 120 mV.

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.

Hi

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

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

Types of Articles

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Reviews. These are articles that review current research work in the area that has major advancement or of interests by the readers. The papers may be invited and/or reviewed by referees and the authors are fully responsible of their articles. Contributors must follow the general instructions where applicable.

Short research communications. These are short reports of experimental research, which have considered that the results should be distributed quickly. The experimental data have currently displayed in any scientific meeting are also encouraged for publication. The maximum length allowance will be 1500 words.

Editorial comments. These can be invited articles commenting the research article published in the same issue of the journal or unsolicited commentaries on current topics of interest. The maximum length allowance will be 1500 words.

Case report. A maximum of 2 figures and 1 table are allowed with up to 10 references.

Letter to the editor. A letter should be no longer than 1000 words without figure or table and should discuss or comment on an article previously published in the JPBS. Up to 10 references are allowed.

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 believe the main challenge is to attract the attention of the students. In today's world it seems that they are more interested in practical applications. As chemistry is in almost everything, tries to bring practical situations and then comments on the chemistry behind the phenomena. This is the strategy I have been using with my students at the University.

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

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

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.

A famous Serbian Schliwowitza - a plum brandy.

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.

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.

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.

Please see the link below.

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

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

you can heat the material to 200 °C to remove epoxy if high temperature is acceptable for you.

Which genus/species give date range for early Miocene in Mediterranen basin?

Iris has a good point. And I would add use of a low-substitution resin.

The literature indicates that those of low chemical composition are the most stable, as is the case of B12N12

Roh,

I'm happy you find your answer. But note that everybody is free to answer as they desire. It is up to you to decide which one work for you. Their answers are also valuable but might not point out what you meant. Then simply ignore them. They may be of interest to other people who have a similar question in the future.

Good luck.

Dear Ibrahim Mohammad ,

presence of salt can affect solubility of gases. Many cations and anions of salt will interact with water which affects the short-range order of water molecules and reduces the available (free) water molecules to interact with gases.

Have a look at following paper:

In order to increase the gas solubility I suggest you to use reverse osmosis water (use ultra-pure water).

Regards, Rob.

Hello

I hope this could help you

Good Luck

The ratio should be 1%, ie 1gm detergent in upto 100 ml water

I think it will function in the same way but Viscosity of mineral oil and paraffin oil are different, so you have to apply high/low flow rates for the paraffin oil compare to mineral oil such that it will form the droplets/particle synthesis.

Piranha, which is a hazardous mixture of sulfuric acid and hydrogen peroxide

Niloofar Mousavipak I'm using OPUS or EFTIR with their libraries. also i have some paper with some information about bound and their wave numbers.

Dear Vinay Khandelwal, my proposed explanation is as follow. I think the metal surface plays an adverse effect on the hardenning of the coat film. It inhibits and retards the Polymerization process. The upper 2nd coat forms rapidly because the course of the polymerization is not affected by the metal surface since it is isolated by the first coat film. The attached file give more details. My Regards

You have not stated which column yet, so we can not help you. Please contact the person who wrote the method you are duplicating and/or the column manufacturer once you know which column it is for more information.

In Newtonian fluids, this value doesn't change, but with non-Newtonian fluids, apparent viscosity is directly affected by the shear rate. It can be calculated by dividing shear stress by shear rate. Relative viscosity: Relative viscosity is important for non-Newtonian fluids, specifically polymers. The apparent viscosity largely changes with the shear rate. This because the shape and rotation speed of the mixing impeller in a mixing vessel determine the shear rate. To understand why this is, one must look at the microscopic level at the differences in how molecules are arranged depending upon the flow. Processes with non-Newtonian fluids passing through a pump, a filter, instruments with a smaller diameter than the pipe size, or those flowing through a sampling valve may be significantly affected. The requirement to have the precise flow conditions in effect during measurement of viscosity is why the use of an in-line viscosity measurement device for measuring non-Newtonian fluids is so useful in process quality control.

Hi Johnson,

You may make inquiry at Alfa Chemistry in New York, they offer kinds of chemical for research use.

I agree with the answer that was provided by Dr. Jasim Hassen .

Hello, shelf life for PBS products are about 1 year at 20^C no chemical reaction would undergo in PBS and pH should remain stable as least energetic state has already been reached. If you see any changes in transparency or your PBS solutions become turbid, it should be discarded.

Good luck!