Chemistry - Science topic

Rajarajeshwari Thada when i see about the chemi doc instrument or the images of micro array membrane using chemi doc instrument then please do have a look at the link shared herewith and am sure this will be helpful as well

Chemidoc imaging system is also shown here with the attached link of PDF

This looks like it could come from the low wettability of the water on your substrate. You could measure the contact angle with your solution to make sure. In case this angle is effectively high you could try to do a plasma treatment of your substrate to increase wettability (if it can support it) but the best option would probably be to change the solvent.

It depends on what you wish to do. e.g. Add HCl, and Cl2 gas will evolve.

See if any oxgen scavenger can be used for removing it

Thanks all for your valuable inputs.

Prof. Hatsuo, its a short fiber reinforced polyolefin composite. it would be great if you can advise any standard ASTM/ISO or research article dealing such kind of problem.

For landfill, is it the anaerobic degradation that we should look for?

Dear Neha Baqai

In most cases, the result of expression analysis by two different chemistry taqmen and cyber results may be comparable but at first, the phylogenetic relationship between the target organisms needs to be checked. Thanks.

regards

Marzan

Dear Surjeet Chahal many thanks for your very interesting technical question. Spindle-shaped cerium oxide nanomaterials have been observed by other researchers before. In this context please have a look at the following potentially useful articles:

This paper is freely available as public full text on RG.

(see attached pdf file)

Nucleation and Growth of such cerium oxide nanomaterials have been outlined in detail in the following relevant article:

Good luck with your research and best wishes! 👍

Dear Milad Boostani , high dispersibility of graphene quantom dots originates from their extremely low dimentions along with existence of numerous oxygen-containing functional groups in their chemical structure which not only provide multitude of hydrogen bondings with water molecules but give rise to a high zeta potential as well. Although the type and distribution of GQDs' functional groups vary from one case to another depending on the precursor used and the synthesis conditions, the main cause of such a remarkable zeta potential in conventional GQDs is the carboxilic acid functional groups located at the edges. However, in some cases in which an amine-based precursor is used, the resulting particles have positive zeta potential owing to the protonation of amine group. All in all, as I said, the small sizes of GQDs (large surface to mass ratio) and their high zeta potential either positive or negative are the key determinants of this matter. For further details you can read the following papers.

Good luck,

I assume you do mean "molecular magnet" rather than the more common ferrofluid, right? DIY ferrofluids are doable at home, and make a lot of sense for science demonstrations. There also seems to be a lot of recipes for those.

I am not sure of whether any single-molecule magnet is doable in a home lab, but in any case they won't do any good since one needs specialized equipment and cooling well below liquid nitrogen. I do know that only a few molecules present magnetic hysteresis at or near liquid nitrogen temperatures, and their synthesis is very challenging.

In case you mean "molecule-based magnets" (something like this ), then the question is legitimately hard but maybe possible. I am not familiar enough with this to provide a good answer though.

The following discussion seemingly can be found of some interest, concerning to your query:

Dear Shruti Tewary thank you for your interesting technical question. The principles of acid-base reactions in organic chemistry are the same as in inorganic chemistry. They are also based on the Arrhenius, Bronsted-Lowry, and Lewis Definitions. For some general information, please have a look at the following instructive video tutorial series

Also please have a look at the following useful link:

Dear Arthur Kaneps many thanks for your interesting technical question. I agree with the previous abswers provided by Christian Gege, Thomas Mayer-Gall and M Venkata Krishna Reddy in that esterification with acyl chlorides or carboxylic acid anhydrides in the presence of pyridine or triethylamine is a safe bet. Unfortunately you did not disclose in your original question which acyl chloride you are planning to use.

I found two relevant articles in the chemical literature about the esterifcation of allobetulin in which the use of the free carboxylic acids R-COOH is reported. For example, allobetulon reacts directly with benzoic acid, phthalic acid, and succinic did in the melt (5 min at 230 °C) to give the corresponding esters:

Similarly, a series of allobetulin esters with R = CClH₂, CF₃, CClF₂, and CCl₃ have been synthesized through acylation of allobetulin with the free haloacetic acids R-COOH in CHCl₃ at 70°C.  The resulting esters were obtained in high yields, and the reactions did not require the use of a catalyst:

Rasayan Journal of Chemistry, 2019, 12, 1032-1037

Unfortunately I don't have access to this rather exotic journal, but I think the general indormation given in the Abstract is already quite useful.

Good luck with your research! 👍

Thanks Shrikaant Kulkarni, Udaya Jayasundara and Artem Musiienko for your kind answers.

Thanks, it is interesting to question, you could look at the article

hi

the below links may be helpful

wishing all the best for you

Dear https://www.researchgate.net/profile/Aarif-Shah-2 , Just ensure that DAD detector is working on VW ( Variable Wavelength ) priciple but UV detector is working on Lambert Beers law principle entirely different . You are again requested to calculate manually % RSD between two wavelengths ( not more than 2 % ) .Please go through the deatail - https://www.ssi.shimadzu.com/products/liquid-chromatography/knowledge-base/hplc-basics/uv-vs-pda-detectors.html

Further manual calculation of % RSD are suggested since two instruments are on defferent platform .

Hi Eric,

I no longer work at Horiba and am not familiar with the latest software. I was going to forward this to my former colleague, but it's probably best/faster if you just call their help desk. Someone can answer this for you in a couple minutes.

Dear Jitesh Pandya many thanks for your very interesting technical question. te synthesis and processing of lead-perovskites is an important current research topic worldwide. Thus there is a large body of scientific literature available worldwide. From the outside it is difficult to solve your specific problem without knowing the detailed reaction conditions (target compound, starting materials, solvent etc.). For an alternative synthesis of methylammonium lead bromide perovskite nanocrystals using ionic liquids please have a look at the following relevant article:

Unfortunately this paper has not been posted as public full text on RG. However, the Supplementary Information is freely available (see attached pdf file).

Also please have a look at this potentially useful paper:

There are also a number of interesting references describing the crystallization of lead bromide perovskite materials. For example, please go thorough the following Open Access articles:

and

Moreover, I strongly suggest that you use the "Search" function of RG to find and access relevant articles in this field. As an example, you could search e.g. for the term "lead bromide perovskite" and then click on "Publications":

This will provide you with a long list of useful articles.

Dear Sina

Since the difference in bulk densities of nickel and cobalt is very low, I think you can not use the conventional routes in the powder processing. I think one suitable way is to leach the powder in a dilute sulfuric acid solution. Then, extractants such as CYANEX272, LIX 272 and Ionquest 290 can be used to separate cobalt from the solution. Eventually, you can electrowinning to produce high purity nickel deposits. For more details, take a look at the following reference.

"Extractive Metallurgy of Nickel, Cobalt and Platinum Group Metals"

Best of luck

Beside what mentioned by my colleagues above, I would suggest stating the percentage of the different excipients you used in your formulation, and also how did your tablet behave in the disintegration test ? if it behave similarly, I will suspect the magnesium stearate, try to decrease its percentage and blending time with magnesium stearate as well.

In Fluid Mechanics, to get a Ph. D. is a developmental journey, which depends on many factors. In physical modeling takes 5-8 years. This is due to the fact that experimental work requires necessary to process and analyze a large number of research results, constantly calibrate the sensors, and determine the noise of the stands and the environment. But time can change dramatically depending on the results obtained.

Dear Mheran there are many chemical admixtures (superplasticizers) use to modify the properties of fresh concrete. The best approach is to perform a test using various types of superplasticizer and select the best one. An empirical selection is not always efficient.

Dear Mohammad Javaherian many thanks for the interesting technical question. It's interesting to see that there are already some rather differing answers. I agree with Sebastian Jung in that the "alpha effect" does not play any important role here. I don't see a mesomeric effect of the methyl groups either because the phosphorus atom has a free electron pair and not a positive charge. Instead, the electron-withdrawing oxygens in trimethylphosphite will lead to the effect that the free electron pair at phosphorus has more s-character, making P(OMe)₃ a weaker nucleophile. In contrast, the free electron pair at the P atom in trimethylphosphine has more p-character so that PMe₃ is the stronger nucleophile and a better donor ligand toward transition metals. For some very useful overview on the different properties of various ligands please have a look at the following article:

Dear Arina Levina thank you for your interesting technical question. The question would certainly get more qualified answers if you explained what you mean by DES. I had a hard time finding it out. When you check the Wikipedia entry on the abbreviation DES you find no less than 26 different meanings of DES on the English page, from "Data Encryption standard" to "Deep Eutectic Solvent" (https://en.wikipedia.org/wiki/DES).

Since you were talking about hydrogen bonds in your original question I assume that in your case DES stands for desloratadine, right?

In this context, please have a look e.g. at the following useful link which is freely available as public full text:

For the stability of desloratadine in water, please also see the following relevant article:

It could also pay off to use the "Search" function of RG to find and access other useful references on this topic. Just search for "desloratadine" and then click on "Publications". This will result in a large number of interesting articles:

Nanoparticle-Based Strategies to Combat COVID-19

Hi Pranav, could you find the answer?

May be your dye has not been internalized in to the cell and retaining in the surface as an aggregate. Probably you may need to double check your staining protocol and provide sufficient time for the internalization. I would highly recommend you to try the same dye/method in a different cell line as a control. Hope this help!

Dear Ekaterina E. Khramtsova please have a look at the following useful link:

Dear Shaun,

Do you know about Erasmus program studying abroad

here is the link

all the best,

Sami

Shortly, the Impact Factor(IF) related to Clarivate Analytics. Whereas, CiteScore related to Scopus database.

For more details, please go through this paper

Regards

Dear Natrawee Khetwunchai thank you for your very interesting technical question. Please find cited below some research articles in which the mechanism of gold leaching using Fe₂(SO₄)₃ has been investigated:

1. Recovery of Gold from the Refractory Gold Concentrate Using Microwave Assisted Leaching

(see attached pdf file)

2. Bacterially generated Fe₂(SO₄)₃ from pyrite, as a leaching agent for heavy metals from lignite ash

This article is freely available as public full text on ResearchGate.

3. Leaching kinetics of gold bearing pyrite in H2SO4−Fe2(SO4)3 system

(see attached pdf file)

Hi Taufiq Ahmad . From literature, it looks like the BCA assay works only with secondary amines. As the secondary amines form a colored chelate complex with cupric ions (Cu2+) in an alkaline environment and form Cuprous (Cu+) ions. The Cuprous ions form a complex with the BCA assay.

In experience I have found a linear response of BCA assay with Primary amines too. I do not know what the exact mechanism is for that. Did you find it out?

Anurag Roy perfect question and you can surely have a look at this blog with many experts from around the globe and they will help you for sure

you can also find some books listed there too,....

Thank you both!

Hi Gregoire,

Thanks a lot for the information and the links! Really helpful!

Cheers,

R

You are very welcome, Dr. Marziyeh Mohebbi

Dear Asfak Patel thank you for your interesting technical question. It is known that the contact of metallic copper with sodium chloride solutions in the presence of oxygen (air) can lead to corrosion of the metallic copper. Did you check the composition of the precipitate?

For some general information about copper corrosion in NaCl solutions please have a look at the following useful articles:

1. Investigation of copper corrosion in sodium chloride solution by using a new coating of polystyrene/g-C3N4

This paper is freely available as public full text on ResearchGate.

2. Influence of pH and Chloride Concentration on the Corrosion Behavior of Unalloyed Copper in NaCl Solution: A Comparative Study Between the Micro and Macro Scales

(see attached pdf file)

To ensure understandability, reproducibility, and replicability, the research methodology must be clearly spelled out and expatiated upon. In other words, all procedures carried out in a study must be explained in detail in the methods section, leaving no room for whats or whys. The following could render more insights.

PLOS. (2021, February 26). How to write your methods. https://plos.org/resource/how-to-write-your-methods/

USC Libraries. (2021, March 18). Research guides: Organizing your social sciences research paper: 6. The methodology. Research Guides at University of Southern California. https://libguides.usc.edu/writingguide/methodology

Thank you for sharing idea Madhukar Baburao Deshmukh

M. Mozammel Hoque,

Organic Chemistry

Textbook by T. W. Graham Solomons

Depends on the size of your batteries, and how many cells each one has. In parallel circuits, currents are added but voltages need to match. So for example, you shouldn't put a single 4V Li cell in parallel with a single 2V Pb cell because then the Li cell will apply a net voltage of 2V to the Pb cell.

I agree with you Mr. Naimish Kumar Verma.

Dear Lokesh Murali thank you for this interesting technical question. I only found a references in which the combination of nickel selenide with Ti3C2Tx has been reported:

This paper is freely available as public full text on ResearchGate.

Dear Ma Gabris thank you for this interesting technical question. As an inorganic chemist I'm not really familiar with this topic, but I can try to suggest to you a few potentially useful articles. Please have a look e.g. at the following papers:

1. Can a single molecule trap the electron?

This article can be freely downloaded as pdf file from the general internet.

2. Functional group dependent dissociative electron attachment to simple organic molecules

This article is freely available as public full text on ResearchGate.

I think these attachments can be useful for you

Maybe that helps you: https://typeset.io/formats/elsevier/analytica-chimica-acta/b2233832fb58f1aaa72b712a67a0cc69

I am guessing some kind of click chemistry so some kind of amide or alkyl group that would then be complementary to group on what you attach to.

The University of Jena, Germany, and the New York State College of Ceramics at Alfred University, in the USA, are among the most specialized and traditional centers in glass science.

The Federal University of Sao Carlos, in Brazil, also offers very equipped facilities, if you prefer a tropical country.

Of course, there are a lot of other good institutions... it depends on the subject you are interested in within the topic of glass chemistry. For example, if you want to research Bioactive Glasses, the Imperial College London has nice researches in this field.

Both the PBE and PBEsol are first-principles generalized gradient approximations (GGAs). A simple modification of PBE is the PBEsol functional, which differs from PBE only in two parameters, and is designed to improve upon PBE for equilibrium properties of bulk solids and their surfaces. The main difference between them is that they are based upon different selections of exact constraints to satisfy.

At the GGA level, but not at the higher meta-GGA level [Meta-GGA DFT functional in its original form includes the second derivative of the electron density (the Laplacian), whereas GGA includes only the density and its first derivative in the exchange-correlation potential], one can at most satisfy two out of the following three constraints exactly:

1. second-order gradient expansion for exchange.

2. second-order gradient expansion for correlation

3. the local spin density (LSD)-like linear density response of a uniform electron gas.

The PBE satisfies numbers 2 and 3 but not 1, whereas the PBEsol satisfies number 1 and compromises between numbers 2 and 3.

From the performance perspective, the PBEsol describes more correctly the stereoelectronic (SE) effects in many hydrocarbons than many other DFT functional approximations, applies to densely packed solids, and is also useful for large organic molecules (in the absence of free atoms). On the other hand, although no GGA without a dispersion correction can account for long-range correlation, the PBEsol (after the error cancelation between exchange and correlation) can apparently account for medium-range interaction better than the PBE.

Dear Daniyal Ahmed just in case that this question is still of interest to you: The article cited below contains a detailed description of how to make oleum in the laboratory:

Personally I would suggest to buy oleum from commercial sources as it is an industrial product manufactured on a large scale.

Dear Talal Ashraf there are two potentially useful article on this topic available as public full texts right here on RG:

1. Predicting Feasible Organic Reaction Pathways Using Heuristically Aided Quantum Chemistry

2. Neural networks for the prediction organic chemistry reactions

Also, see the following RG links.

EIS Spectrum Analyser is a very good tool and it's open sourced: http://www.abc.chemistry.bsu.by/vi/analyser/

You can also use MATLAB to fit EIS data, though can be a bit tricky to start. https://www.mathworks.com/matlabcentral/fileexchange/19460-zfit

Hope this helps Ken!

Good journals accept submission with clear authors contributions to submitted work. First author is considered the main figure for the research item

Follow

Dear Ethan,

There is a similar question which were posted in the research gate forum. This could answer your question. Please see the following link

Best wishes

Xuhua

Since the pKa's of acid and base are far apart, you probably start with a near neutral solution before you add the extra weak base. Then you pH goes up into the alkaline area.

Normally you prepare a buffer by either using a weak acid and adding about half of its concentration of a strong base or vica versa. I do not understand that you call a mix of a weak acid and a weak base a buffer.

What is the purpose of your 'buffer' ?

Sodium metabisulfite (Na₂S₂O₅) dissolves in water as sodium bisulfite: Na₂S₂O₅ + H₂O → 2NaHSO₃. Sodium bisulfite is converted to sodium sulfite (Na₂SO₃) by

NaOH. The solubility of sodium sulfite (Na₂SO₃) in the alkaline solution may have been exceeded due to the common-ion effect, as Na⁺ is also contributed by the NaOH aq. sol.

Ok sir !

Thank you and will update you too..

Dear Dr. Shafeek Buhlak ,

I suggest you:

-Advances in Nanotechnology and Its Applications

Ahmad Tariq Jameel and Abu Zahrim Yaser Editors

Publisher: Springer Verlag, Singapore

Publication year: 2020

ISBN 10: 9811547416

EAN: 9789811547416

-Nanotechnology

Paresh Chandra Ray Editor

Publisher: Nova Science Publishers Inc

Publication year: 2018

ISBN 10: 1536138894

EAN: 9781536138894

My best regards, Pierluigi Traverso.

Thanks for the multiple replies.

The probability of pick-off annihilation in positronium (Ps) is primarily due to electron density, as Rüdiger Mitdank has pointed out. It is described by the overlap of the positron and electron wave functions. However, in practical terms, it is not determined by that alone, but is also affected by various environmental factors. In this discussion, I would like to get into these factors.

For example, water and many other liquids expand as their temperature rises. Since expansion decreases the molecular density (electron density), it is assumed that the higher the temperature, the longer the Ps lifetime. However, this assumption is not true. In fact, the lifetime of Ps is shorter in warm water than in cold water.

Similarly, the relationship between Ps lifetime and pH is not easy to estimate. Therefore, we should base our decisions on experimental data.

Most of the basic Ps chemistry was done in the 1960s and 1970s. In those days, the resolution and stability of measuring instruments were not as good as they are today, and the use of computers was limited. Straight lines were drawn with a ruler on hand-drawn one-log graphs. Therefore, the environmental factors that were reported to be "independent" at that time may or may not be due to the lack of measurement accuracy. As the application of positron science to medicine has progressed, motivation to revisit some of the issues has arisen.

I hope somebody will continue to let us know if you have any information on the relationship between pH and the lifetime of Ps. Thank you very much for your time.

Thanks, Jukka. I've gone with ethanol to be safe.

Please Dear Matt Mj

The books below are good for your question.

[1] BARD A.J., L.R. FAULKNER,(1983) électrochimie; principes, méthodes et applications, (chap. IIV, V) MASSON,.

[2] Gallus Z, Fundamentals of Electrochemical Analysis, (1994) Second (revised) Edition, Ellis Harwood, New York, Chap (I-VI).

[3]Girault Hubert H, (2007) Electrochimie physique et Analytique, 2ème edition, presses polytechniques et universitaires romandes, chapVIII,pp (391 -395).

Kafia OULMI

Timothy Braun I am using MFiX for several months and I saw a Barracuda VR. But some reasons (like a budget :) ) I couldn't use a Barracuda.

Each software have different pros and cons for MPIC schemes. Firstly, MFiX is open-source and you can change everything that you want (like a user-defined-function). Also, MFiX has some different discretization schemes, solver types, etc.

Btw, Turbulent solvers are different. I'm working on turbulent case and chemical solvers these days. It seems Barracuda is beginner user friendly, but need to time for learning advanced things for MFiX.

Thanks a lot, it was interesting to read it, but it still did not answer my question about OH-. I feel more and more that nobody knows. One option could be that the OH- goes into the tissues but it is silent about it because it is very difficult to measure. I cannot really see any other solution.

If you want to solve your problem as it appears in the image, I recommend using an equation of state for the enthalpy departure.

I also recommend the following articles:

-A computationally effective formulation of the thermodynamic properties of LiBr-H2O solutions from 273 to 500 K over full composition range

- Exergy calculation of lithium bromide-water solution and its application in the exergetic evaluation of absorption refrigeration systems LiBr-H2O

-Thermodynamic Evaluation of LiCl-H2O and LiBr-H2O Absorption Refrigeration Systems Based on a Novel Model and Algorithm

-Mathematical Model of a Lithium-Bromide/Water Absorption Refrigeration System Equipped with an Adiabatic Absorber

Dear Huyen Tran Dang to my knowledge the formation of difluorosilane, SiF₂H₂, cannot be explained by the reaction of SiF₄ with HF. The latter two compounds will react under formation of H₂SiF₆ (see e.g. the link cited below). I think that the formation of SiF₂H₂ can only be explained by the presence of elemental hydrogen, H₂.

https://brainly.in/question/1115388

Hello Mr. Hajipour

"N" refers to a molecular nitrogen presents in a defined concentration of a molecule or ion. You can find it out by multiplying the molecular weight ratios.

In your example if N in the form of nitrate (NO3^-) is 10 mg, then the concentration of nitrate molecule will be 10 mg N*(62 mgNO3/mmolN)/(14 mgN/mmolN), i.e. 44.28 mg NO3^-.

Same concept is valid for any other atoms and molecules.

Regards

Hi Simon, I have used many cleavage cocktails and scavangers for peptide cleavage. My opinion: The cocktails aren't that stable, especially the TIPS and thioanisol. Maybe one week is fine if you keep it in the freezer. I would recommend to start with a fresh cocktail each day for best results.

Dear Prof James

thanks for sharing your nice answer

Heating is to be done

I only want to get rid of the trapped gas and bubbles first

Thanks for your answer !

5%Ti 1%B add as a master alloy of Aluminum in wieght ratio 100:1 Kg

Thank you for your answer,

Nice question

Good question

لم استطيع التحميل

The experience of the development of science shows that the quality and significance of a scientific discovery and its usefulness or harm for human civilization are inversely dependent on any expectation, be it the expectations of the entire scientific community, and even more so the expectations of a "non-professional" society. For example, it is known that the great Rutherford, who discovered the atomic nucleus, believed that his discovery would have no practical application.