Chemistry - Science topic

Dear Prof. Mario Pagliaro, Preprints are defined as an author’s version of a research manuscript prior to formal peer review at a journal, which is deposited on a public server. ResearchGate (RG) said about "Preprints": early-stage research. On the other side, RG is not a publisher and, in turn, uploaded unpublished text is not regarded as a publication. Hence, a preprint is an author's own original or draft version of their paper before any peer review has taken place and before it is published.

Before answering this valuable question, please let me give my own opinion about the preprint dilemma (مُعضلة ما قبل الطباعة):

I have a different perspective on uploading any preprint anywhere before it has been published. Why do you let others know about your insights and methodologies before publication? You should avoid telling the other researchers about the details of any one of your papers until it has been published and seeing your name by yourself. You may say that I am somewhat old-fashioned, but I have a different perspective on uploading any preprint anywhere before it has been published by your name. My advice is not to put your research anywhere until it is published. It is a security issue:

Finally, for the coming future, do not upload any paper anywhere until it is published with your name. Even if it is a "preprint"! For the time being, If you had done something like that as a "preprint", for instance, I advise you to delete the preprint from any elsewhere and wait for two months before sending the paper to any journal.

Do not breathe dust/fume/gas/mist/vapours/spray. Avoid breathing dust/fume/gas/mist/vapours/spray. Use only outdoors or in a well- ventilated area.

Dear Noor Ul Ain

You can use the :-

- ChemReaX (is a free web app for modeling and simulating basic chemical reactions)

- Molecular Workbench

Best Wishes...

The paper you cited also includes the combustion of methane to provide the energy needed to account for the endothermic reaction as well as bringing the reaction temperature to that where the reaction occurs (850 C). For the combustion reaction, the LHV of methane is appropriate, where as for the SMR reaction, the heat of formation is appropriate. The reactor(s) consist of tubes packed with catalyst where the SMR, WGS, and HB reactions occur. On the outside of the tubes, CH4 is burned using either air or pure O2 to provide the energy needed for the process.

Dear all, following a list of interesting books. My Regards

- Fundamentals of Materials Science and Engineering: An Integrated Approach, William D. Callister, David G. Rethwisch, 5th Edt (2015).

- Materials Science and Engineering: An Introduction, 10e WileyPLUS NextGen Card with Loose-Leaf Print Companion Set, Callister Jr., William D., Rethwisch, David G. 10th Edt (2018).

- The Science and Engineering of Materials, Donald R. Askeland, Wendelin J. Wright. 7th Edt (2014).

- Materials Science and Engineering: A First Course, V. Raghavan, (2004).

- Foundations of Materials Science and Engineering, Willaim Smith, Javed Hashemi, 6th Edt (2019).

At initial concentration, atoms of the salt molecules have not ionized to form part of the solution. The already auto-ionized water ions(H+ & OH- ) tend to interact with the salt molecules until complete ionization can take place.

Purification of chemicals is a large branch of chemical technology, with a large number of non-universal methods. In the case of NaCl, it is sufficient to simply recrystallize it from an aqueous solution.

dear Dr Phil Geis

the purpose is to obtain the odor of the essential oil or to just neutralize the chlorine odor without touching the performance of HOCl

in case of titration, 0.1 N sodium carbonate solution the required hcl concentration is concentrated or 0.1 N solution used.

One of the issues that is holding the concept of an RNA world back from being more scientifically useful - irrespective of whether there ever was such a thing - is that we don't use the idea in the scientific way it was intended. Just like any other prebiotic scenario, it is not (nor has it ever been) a scientific hypothesis. In fact, scenarios are usually not intended as such. Scenario authors from all niches (including RNA world) have pointed out that scenarios themselves are untestable. However, they guide thinking and allow to conceive of hypotheses that are testable. If we go through the old literature we find very explicit passages to support this fact.

For the specific authors advanced in the question, G.F. Joyce and L.E. Orgel, we have a passage from 1999 in "prospects for understanding the origins of the RNA world". (The RNA World 2nd ed. 49-77).

"The presumed RNA World should be viewed as a milestone, a plateau in the early history of life on earth. So too, the concept of an RNA World has been a milestone in the scientific study of life's origins. Although this concept does not explain how life originated, it has helped to guide scientific thinking and has served to focus experimental efforts."

You can find this point of view expressed in foundational work for all niches related to the popular scenarios today. But you can also find it for scenarios most people in origins have never heard of. E.g. the idea that celllular life started with terpenoids found in G. Ourisson and Y. Nakatomi's "the terpenoid theory of the origin of cellular life: the evolution of terpenoids to cholesterol. (1994) Chem & Biol. 1 11-23".

"The hypothesis provides an attractive way of ordering the terpenoids: like all evolutionary theories, it cannot be tested directly. The ideas summarized here do, however, suggest a multitude of experiments having some bearing on the fundamental and fascinating question: how did the first cells appear? We hope to carry out some of them."

A related line of thought - but highly influential - is the exposition by Harold J. Morowitz from 1992 in his book "Beginnings of Cellular Life: Metabolism Recapitulates Biogenesis". If we go to the conclusion, we find this explicit clarification on the distinction between a genuine scientific theory and a scenario:

"at this stage of the thought process, it is important to focus on the hypothesis that intermediary metabolism recapitulates prebiotic chemical evolution. This hypothesis is not a strictly vulnerable theory in the Popperian sense, but it does provide us with a valuable heuristic method for using modern knowledge of biochemistry to search for events that have left their trace. If the intermediary metabolism of autotrophs does not recapitulate biogenesis, then the discontinuities will have to be explained."

More than 2 decades back, many authors made a clear distinction regarding this nuance. Scenarios are here to help: they guide thinking and design experiments. They only guide thinking in a scientifically meaningful direction as long as we can easily abondon scenarios and enthusiastically continue replacing them with new, more informed scenarios. A situation where a scenario gets entrenched and where researchers treat it as a scientific hypothesis is - by construction - hard to escape.

In fact, this is exactly the situation that many researchers have described around the 80s, when criticism mounted against the prebiotic broth scenario. The passage from Wächtershäuser's 1988 "Theory of a Surface Metabolism" is telling:

"The prebiotic broth theory has received devastating criticism for being logically paradoxical (11, 135), incompatible with thermodynamics (11, 144, 160), chemically and geochemically implausible (134, 136, 144), discontinuous with biology and biochemistry (160), and experimentally refuted (135, 160). The reason for the tenacity with which it is retained as accepted dogma has been forcefully and clearly stated by Scherer (126): "If this rejection is substantiated, there will remain no scientifically valid model of the selforganization of the first living cells on earth."

Clearly, the broth scenario had overstayed its welcome. One reason for this is that its 'claims' (which for a scenario can only be speculations) were too much in contradiction with claims from fields of science that do not suffer the same restrictions when it comes to testing and refuting their theories. One example of a very controversial idea that can be found in Haldane's formulation of a broth scenario, is the purported necessity of a long, highly functional protein randomly emerging from a soup, as an extremely rare event: we expect this to be prohibitively unlikely and hence a far from parsimonious explanation.

Quite a few of the critiques voiced against the prebiotic broth scenario are equally valid critiques of some scenarios we have today, including RNA world.

The RNA world is an old and multifaceted concept. There are contrasting formulations that make different claims (to be interpreted as speculations) about history. As with the prebiotic broth scenario (and any scenario), it has raised genuine scientific objections. These have remained largely unadressed, in spite of its long dominance.

It is instructive to bear in mind that scenarios don't come from nowhere. They're fairly detailed speculations about purported historical events. To make them, each author makes assumptions. Some of these concern speculations that later became testable, e.g. about chemistry and physics. You will find different scenario authors make different assumptions and different arguments (and flaws therein). There's an inevitable bias here with respect to the fields an author is trained in. Some of the foundational assumptions in popular scenarios like RNA world are at least 50 years old, but some unchallenged assumptions date back to a literature that is more than a century old. A time before IUPAC, modern quantum mechanics, genetics, and so forth.

That has been enough time to forget that scenarios like RNA world are by construction not testable hypotheses and that they were not intended as such. Scenarios are here to guide thinking, to inspire experiments. The best thing a scenario can do for us, is generate insights that spur us to change the way we think and thereby necessitate replacing our old scenarios with new ones, and repeat the cycle. The science coming out of the community today is a lot more conducive to doing that than previously.

The same cannot be said for the rather myopic RNA-centric framing of a question in the cited passage, which attempts to elevate RNA world to more than a scenario. Rather than forcing ourselves to think about the rather narrow and outdated proposal by Joyce and Robertson, ("consider the alternative possibility that RNA was preceded by some other replicating, evolving molecule"), it is more productive to critically revisit all the things that have been assumed and argued when the concept of an RNA world was conceived and how which of these premises are considered valid or plausible today, and which ones back then. Is there a formulation of RNA world for abiogenesis that is logically sufficient? And if so is it logically necessary that abiogenesis proceeded this way?

It is also instructive to check how much of the logic was sound. e.g. the rhetorical tricks employed in RNA world introduce all sorts of hidden assumptionsm.

As an example of the latter: some still justify an RNA world by the party trick 'chicken-and-egg' question 'protein or RNA, which came first?', only to conclude with 'RNA, it encodes proteins' and hastily conclude with an even stronger 'RNA-first' for abiogenesis. 'chicken-and-egg' fallacies are nothing new in origins. In fact, they were already identified as such long ago. E.g. in chapter 8 of "Seven Clues to the Origin of Life (1985)" by Cairns-Smith, there's an illustrated passage detailing that these types of paradoxes in origins frame the question in a manner that prevent us from considering scaffolds.

"

The fact is that even the so-called simple organisms such as E. coli are very complex enterprises with all sorts of things going on together. There is plenty of scope for accidental discoveries of effective new combinations of subsystems. It seems inevitable that every so often an older way of doing things will be displaced by a newer way that depends on a new set of subsystems. It is then that seemingly paradoxical collaborations may come about.

To see how, consider this very simplified model - an arch of stones: This might seem to be a paradoxical structure if you had been told that it arose from a succession of small modifications, that it had been built one stone at a time.

scaffolds that starts like this:

This might seem to be a paradoxical structure if you had been told that it arose from a succession of small modifications, that it had been built one stone at a time. How can you build any kind of arch gradually? The answer is with a supporting scaffolding. In this case you might have used a scaffolding of stones. First you would build a wall, one stone at a time:

Then you would remove stones to leave the 'paradoxical' structure.

"

It should be noted that in 2022, even in RNA-world, very few scholars remain that find RNA-first a convincing idea. As a scenario, however, it is not useless: it is instructive to consider what the underlying ideas are that at some point in time made such a highly specific idea compelling to so many of us.

A fixed motif in scenario papers is to start explicitly and implicitly assuming a few things about what chemistry can and cannot do and some properties of abiogenesis. These sort of assumptions used to be spelled out routinely, also outside scenario papers. Let me give two examples.

The original 1953 paper for the "Frank Model" "on spontaneous asymmetric synthesis", has the passages

".. the defining property of a living entity the ability to reproduce its own kind ...

confining attention to chemical molecules, the complexity of any having this essential property of life is likely to be great enough to make it highly improbable that it has a centre of symmetry."

(*I should point out that Frank makes an important error here: the capacity for molecular reproduction is not a molecular property but a property of a reaction network. If we add an additional thermodynamic criterion this property is autocatalysis and we can then check this claim from the IUPAC definition: https://goldbook.iupac.org/terms/view/C00876. It turns out there are trivial ways to make small networks that have this property https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c74d67469df42226f44295/original/emergent-autocat-animation.gif.)

The point to retain here is that Frank considers it to be generally accepted that one can assume this property to be prohibitively rare in chemistry. This belief was wideheld, and we can e.g. read in "the units of selection" (1970) by Lewontin a summary on scientific views on abiogenesis

"The present view ... Since there was no autocatalysis, there was no reproduction or heredity and so no possibility of natural selection."

The coacervates in Oparins scenario were notably invoked to adress this issue.

When it comes to assumptions in scenarios, this systematically involved conjecturing that chemistry 'in the wild' intrinsically and deterministically becomes a 'mess', undergoing no meaningful complexification, and for which no reproduction and evolution can reasonably be expected. From there, it appears that no process of abiogenesis should conceivably occur naturally, and thereafter some specific sequence of exceptional events is proposed as plausible, because it appears to be the sole contender.

Let us make more explicit why this is not an innocent procedure:

We still find our understanding of 'basic chemistry' to be plagued with limitations and long-lived misinterpretations (e.g. 2 days ago we learned that methyl substitution destabilizes radicals instead of the textbook knowledge that it stabilizes them ).

Moving beyond the basics, we by and large lack a lot of formal theory, experiment, or even a simple reference frame for the things that happen then. Joyce and Robertson honor the tradition of purporting from the outset that 'chemistry in the wild' becomes an intractable mess. The issue is that we don't know at all if that's the case. We cannot assume this from the outset, we need to extensively study it. We require extensive experiments and theory and a reference frame for all the phenomenology associatied with complex systems (e.g. multiple components, compartments, multiple forms of nonequilibrium driving, length scales, time scales).

In making the routine assumption of 'messy, intractable chemistry that can neither complexify nor multiply', we have decided in advance that, once we finally understand 'chemistry in the wild' with its 'so-called intractible mixtures', it cannot have any bearing on abiogenesis. Let alone explain it.

That is a disproportionately bold conjecture about fundamental science, and a very consequential one: all historical scenarios - RNA world being one out of many - have been justified by formulating conjectures of this sort (many authors also insist on other properties, e.g. chemistry being deterministic). Clearly, it should be the first priority of everyone in the field to test this conjecture, by extensively and rigorously studying complex chemical systems as an end in itself. If the conjecture is correct, it provides an important validation for historical scenario approaches. If the conjecture turn out wrong, we are in a much better position to conceive of more scientifically informed scenarios, but potentially the approach will change entirely.

In presenting it as such, I am making it appear as if it could be an open question whether the chemical conjectures underpinning our scenarios in origins may be true or not. In fact, we have learned quite a few things in the meantime. And some clumsy mistakes were made elsewhere.

- Determinism:

When it comes to chemistry being deterministic (a key tennet of e.g. Sutherlands scenario and Wächtershäusers surface metabolism): upon critical evaluation of what is known of basic chemistry this idea becomes unacceptable, especially when considering the chemical processes on the surface of a planet, as opposed to a quick reaction in pyrex.

1) insofar as it is reproducible, modern chemistry owes much of it to big strides of standardization in glassware, methodology, synthesis protocols (e.g. usage of stirring bars).

2) lab chemistry exhibits many forms of contingency. This is particularly the case when it comes to phase behavior, e.g. habit modification, polymorphism. Aspirin purportedly has 8 reported polymorphs, phenobarbitone 13.

3) glassware is cleaned between reactions, thereby making successive reactions in the same glassware independent. In nature, this property of independence is absent. In fact, effort to make an evolutionary classification of minerals are rooted in the opposite: that certain minerals start to form conditional on the presence of certain others. (https://pubs.geoscienceworld.org/msa/ammin/article/104/6/810/570840/An-evolutionary-system-of-mineralogy-Proposal-for)

- Autocatalysis:

A first issue to get out of the way is the misconception that autocatalysis is prohibitively rare. A prominent PI in origins (RNA world, not a chemist) told me that chemists throughout history have found exactly one example. Claims about the contents of a literature one cannot realistically have read in a lifetime is a common error we can find in the origins literature. Below are some reviews.

I should stress that these reviews discuss examples from a few niches in chemistry. These reviews do at least allow to have 100s of counterexamples to dubious claims about no autocatalysis in chemistry, but it's only a small fraction. Virtually all branches of chemistry have regular reports of autocatalysis, but very few focus on autocatalysis in its own right. And hence most branches do not review their reported examples.

By critically examining the IUPAC definitions, one can show that autocatalysis is dramatially more widespread than long thought. In part, this is because the definition applies to a wealth of situations where the term is not routinely employed. By examinging the requirements of autocatalysis as an emergent network property, one can demonstrate that this property emerges particularly readily in a heterogeneous / multicompartment context. With the disclaimer that I'm an author I refer to the following:

- Messy chemistry:

Refreshing counterexamples are afforded by the literature on systems chemistry and dynamic combinatorial libraries.

In the context of origins, a recent work that is greatly aiding in fixing our misconceptions is : https://www.nature.com/articles/s41557-022-00956-7

Where a reaction of purported immense complexity is found to exhibit highly reproducible and ordered behavior as function of environmental inputs. How chemistry exactly works on this level is still poorly understood. I think I do, but it'll have to await peer review. But we cannot in good scientific conscience take for granted anymore that chemistry becomes messy and intractable. When we do the experiments, we see something very different.

in conclusion, I want to come back to the final point of the question

No. The sientific community should strive to do what it can justify scientifically. Those that find it fruitful to relegate the RNA world - which is not a hypothesis - are justified in doing so. Notably because it is is founded on scientifically refuted premises and logical errors.

Those that find ways to make it fruitful to keep it are justified in doing so: it's a scenario, one can draw inspiration from it. Perhaps a thoroughly altered version can be developed that fixes previous issues.

Above all else, RNA is an amazing molecule that has been used for fundamental research that concerns everyone in origins, and will continue to do so irrespective of how serious the RNA world scenario is still taken.

What the origins of life community needs, first and foremost, however, is concern itself with more important matters.

Complex chemistry needs to be studied thoroughly on an experimental and theoretical level.

New scenarios are needed. And these scenarios should no longer require chemistry to have properties it doesn't have, and vice versa. These scenarios should also explicitly be appraciated for what they are, an for what they're not. They're here to help, to guide thinking, inspire experiments, produce testable predictions, update our beliefs. They are not scientific hypotheses in and of themselves.

You could made the MS medium and pour in to the glass jar and autoclave with your pressure cooker. Once it cooled down add the hormone by filter sterilization. Good luck

Dear Emmanuel, I suggest studying retention in the context of deep meaningful learning. In this way, retention leads to durable, lasting knowledge and skills tranfer to authentic settings, a staple of quality education. Another suggestion is applying a game-informed strategy such as playful design (playification), gameful design (gamification) or serious games (e.g. escape rooms). Here are some materials on relevant studies that should be useful.

DeLotell, P. J., Millam, L. A., & Reinhardt, M. M. (2010). The Use of Deep Learning Strategies in Online Business Courses to Impact Student Retention. In American Journal of Business Education (Vol. 3, Issue 12, pp. 49–56).

Fragkaki, M., Mystakidis, S., Hatzilygeroudis, I., Kovas, K., Palkova, Z., Salah, Z., Hamed, G., Khalilia, W. M., & Ewais, A. (2020). TPACK Instructional Design Model in Virtual Reality for Deeper Learning in Science and Higher Education: From “Apathy” to “Empathy.” 12th Annual International Conference on Education and New Learning Technologies (EDULEARN20), 3286–3292. https://doi.org/10.21125/edulearn.2020.0943

Herodotou, C., & Mystakidis, S. (2015). Addressing the Retention Gap in MOOCs: Towards a Motivational Framework for MOOCs Instructional Design. 16th Biennial EARLI Conference for Research on Learning and Instruction Proceedings.

Mystakidis, S. (2021). Deep Meaningful Learning. Encyclopedia, 1(3), 988–997. https://doi.org/10.3390/encyclopedia1030075

Mystakidis, S., Berki, E., & Valtanen, J.-P. (2019). The Patras Blended Strategy Model for Deep and Meaningful Learning in Quality Life‑Long Distance Education. Electronic Journal of E-Learning, 17(2), 66–78. https://doi.org/10.34190/JEL.17.2.01

Mystakidis, S., Cachafeiro, E., & Hatzilygeroudis, I. (2019). Enter the Serious E-scape Room: A Cost-Effective Serious Game Model for Deep and Meaningful E-learning. 2019 10th International Conference on Information, Intelligence, Systems and Applications (IISA), 1–6. https://doi.org/10.1109/IISA.2019.8900673

Yang, K.-H., & Chen, H.-H. (2021). What increases learning retention: employing the prediction-observation-explanation learning strategy in digital game-based learning. Interactive Learning Environments, 1–16. https://doi.org/10.1080/10494820.2021.1944219

Dear Sajiya,

thank you for your posting. I will try to give a quick answer on both questions.

1. Where to get a grant.

A) You can look up the DAAD portal (DAAD = German Academic Exchange Programme). In the Scholarship database you will find the most important institutional grants (including Humboldt etc):

B) You check homepages of colleagues if they have open positions. Or you send emails to them asking if they have open positions.

2. How to find suitable places/colleagues for a post-doc?

This depends on what you want to do during your post-doc.

A) You want to continue research on the topic of your PhD. Then it's simple. You know the experts in the field, you check where they are located and you write them an email.

Concerning research especially in Germany, there is an expert on any topic in Germany.

B) You want to switch from your PhD research to something different and you have a specific idea about the topic.

Then you have to find the experts in this new field and write them an email. ...

You can recognise experts in the field from reviews in important journals, from books and book chapters.

C) You want to switch from your PhD reseach to something different but you are not decided what.

No problem, start making up your mind in which direction you want to work: organic, inorganic, bio, materials, analytics, .... whatever. Then check for the hot topics. They will probably lie in the fields of "energy conversion" or "medical chemistry". Having decided what to do, it is like B).

D) You don't care about the topic of your post-doctoral work. You just want to do research in Germany (US, UK, France). Don't get me wrong, but that is a weak starting point for a post-doc application. I am getting such unselective applications very often and I always reject them. The reason is simple. You are a well-educated scientists and you have specialised skills. If you are trying to enter a completely new field, you have no skills at all and why should somebody hire you as post-doc, if he/she can have somebody with broad skills in this topic.

A very last, but important point:

Approaching my colleagues is not always easy. Sending email frequently does not help - they simply do not respond. What can you do:

1. If you tried for a specific colleague and he/she did not answer, modify your application (may it was not good enough), write in more detail why you selected him/her and try again.

2. Try others. My experience is that many of my colleagues do NEVER answer.

3. Maybe you add a sentence to your email like this: If you do not have open positions for post-docs at the moment, or my portfolio is not perfectly meeting your expectations, I would be happy to receive suggestions for other colleagues in the field.

Best wishes

AXEL

Simon Gersib Hi, the resistance of the glass frit ion flows is surely an issue. Have you measured the ac impedance of your cell in the background electrolyte? With your current being 0.27 mA, it means that a resistance of 350 ohm in the glass frit will produce roughly 100 mV voltage drop (iR drop) which is high enough to cause the crossover.

However, I shall point out that in the bridge section of your H-cell, stirring is almost no effect.

I think you should add the conjugate base (CH3COONa) but not NaOH

Have you considered evaporative cooling for your aquarium. As long as the relative humidity in the room is not pushing 100%, you can achieve cooling using this technique. This link will show your how it is done:

Your suspect compound is one with mid-high molecular weight that must be of organic nature. Centrifugating over 5000 rpm will "pelletize" this kind of compounds. Assuming you're working with inorganic or low-molecular compounds it would be a contamination: of your reagents, the DMSO itself or both.

In my experience DMSO is prone to contaminate due his highly miscibility with organic compounds, even some bacterial spores could survive on 99% DMSO. I recommend you to centrifugal your DMSO alone to see if pellets form. If that happens, try using a switch to another batch of reagent, or change to another supplier. You can also try to filter your DMSO with a 0,22 um filter, but I suspect it won't help.

Yumiao Ma Thanks for your reply.

I am looking for sigma *(Taft), sigma - and + with meta and para substitutes.

And I think that in this article there are only Hammett constants? (Benzoic acid).

Si is usually ok to add in bulk pure form. It doesn't readily oxidize. Also on an unrelated note, Si chips look very cool.

The washing with ethanol helps to a deep removal of organic matter. Depending on the further use of it, it could be beneficial.

Dear Jürgen Weippert

By unstable, I mean that the SCF Done is coming out too low than the expected. The target energy is coming from a the Ethanal+OH/O2 system that has been studied in literature that we are trying to emulate. The unit of measurement is in Hartrees

I found these links, hope they are useful:

Based on the following study it has been concluded that Phosphorus measurements by HP-ICP-OES showed accurate results with very small uncertainties (0.1%) can be obtained with ICP-OES on digested DNA as has been seen with single-element solutions also, it is suitable for any size of nucleic acid from nucleotides to genomic DNA.

Hello,

Firstly I would like to give a small correction: the energy density of LFP is lower than other lithium ion batteries. This is mainly due to the lower voltage produced by this anode-cathode pair. I have made my master thesis on this subject 5 years ago so I will give you some information based on what I still remember (keep in mind that some of my references may be a bit outdated).

On the state of charge (SoC) discussion: the major difficulty with LFP is that its voltage-SoC curve is very flat over a large part of its capacity. This means that the open-circuit voltage does not change strongly as the cell is being charged-discharged. Only at the tails of the capacity (generally about < 20% SoC and > 80% SoC) will the voltage change strongly for a change in Coulombs (which can be expressed as the differential voltage, or dV/dQ). A comparison of estimation methods can be found at (Wladislaw Waag, Christian Fleischer, and Dirk Uwe Sauer. Critical review of the methods for monitoring of lithium-ion batteries in electric and hybrid vehicles. Journal of Power Sources) and another good reference is (Wen-Yeau Chang. The state of charge estimating methods for battery: A review. ISRN Applied Mathematics, 2013)

To make a simple but decent estimation of the SoC of an LFP battery, I'd propose you need 1 main piece of battery/cell-related information and one optional piece of information: mainly the voltage-SoC curve at sufficiently high resolution (which can be transformed to a dV/dQ-SoC curve) and additionally a mapping of the internal resistance of the battery over a range of temperatures & SoC. With this information, you can use a current counting algorithm which simply integrates the current (dis)charged by the battery and uses this to determine the SoC. The issue with current counting is that any measurement error is also integrated and over time this results in a large error. There are some simple fixes for this, at least if your use case allows for it. The idea is to reset the counter and SoC at specific moments: the most useful moment is to reset it when the battery is full, is empty, and/or when it is at rest. If the battery is at rest in the "flat" part of its profile you could also reset the counter, assuming your voltage measurement is sufficiently accurate. If at rest for a very high (or low) SoC, reseting becomes more accurate. If there are not many "rest moments" then it becomes more tricky, but you could use the internal resistance map to estimate the OVC of the battery while it is under load (you could even implement a higher order equivalent circuit model of a battery for a better estimation).

You could also use a simple recursive least squares method to estimate the SoC which has been widely documented in the literature (one example is here: Hongwen He, Xiaowei Zhang, Rui Xiong, Yongli Xu, and Hongqiang Guo. Online

model-based estimation of state-of-charge and open-circuit voltage of lithium-ion

batteries in electric vehicles. Energy, 39(1):310 – 318, 2012. Sustainable Energy

and Environmental Protection 2010)

Good luck!

Dear Arina Levina ,

Using the link as indicated by Shoffan Saifullah , the good news is now that your paper is finally published https://iopscience.iop.org/article/10.1088/1757-899X/1212/1/012013 The thing is that “IOP Conference Series: Materials Science and Engineering” is ' suffering' from their own success and are recently even discontinued (see enclosed file) in Scopus.

The reason is most likely the enormous increase in number of accepted and published papers over the last few years which can be seen by clicking on “Scopus content coverage” here https://www.scopus.com/sourceid/19700200831

I think that the people behind IOP now try to ‘spread’ the papers over more than one year so that the number of papers published annually goes down again towards more acceptable/realistic numbers (at least in terms of inclusion criteria for Scopus).

So, at the very best this is a desperate attempt of the publisher to correct their suspicious behavior (by publishing too many papers in a year which raises questions on how to maintain scientific standards/quality control). This victimize researchers like you who learn the hard way how a publisher is trying to get their act together (again).

Best regards.

In principle silica is more sensitive to hot concentrated base than titania. However, a "quartz" substrate, whether silica glass or real crystalline quartz, is dense and etches very slowly, while your titania is probably deposited from the gas/plasma phase and not very dense. Selectivity may go the "wrong" way.

HF-based solutions will also attack both silica and titania, as you know. You may be able to find conditions of concentration and pH where silica will etch faster than titania, but to etch away the substrate while keeping the (presumably much thinner) deposited film is asking much.

One option I would consider is to interpose a thin Ti metal between the silica and the titania. Ti metal etches very fast in HF, even dilute HF, so you may be able to lift off the titania film without much damage. However, if the titania requires high-temperature annealing it is possible that the Ti will react with the titania to form TiO_2-x.

For CaO catalyst the best methanol/oil ratio is 12 (molar ratio).

The only N protection that is stable enough to allow typical n-BuLi chemistry of which I am aware is to attach two benzyl groups to a primary amine nitrogen, one benzyl group to a secondary amine nitrogen. Removal is by hydrogenation in the presence of one equivalent of HCl added to an ethanolic solution 0.2 M in your benzyl-protected amine derivative, where the HCl is added in the form of 1 M aqueous HCl (the ethanol can be 100% anhydrous or 95% ethanol). The typical catalyst for this is 10% Pd/C. The typical reducing agent is H2 at 60 psi. Typical times for complete removal vary depending on steric crowding around the amine group. PMB (para-methoxybenzyl) is easier to remove by both hydrogenation and by treatment with various acids.

A more thorough discussion is available if you have access to Green's book of protecting groups (Online ISBN: 9780470053485). More rugged groups each have their own problems. For example, a primary amine treated with succinaldehyde [HC(=O)CH2CH2C(=O)H] gives a pyrrole that can be cleaved back to an amine under various conditions. Converting the amine to a succinimide followed by TMSCl and a base gives an easier to remove 2,5-bis(trimethylsilyloxy)pyrrole. 1,2-bis(chlorodimethylsilyl)ethane and base protects the amine as 5-membered ring stable to base but labile to acid and TBAF.

You can mask the amine group as some other group; phenylselenyl chloride makes a phenylselenylamine; similarly phenylsulfenyl chloride makes a phenylsulfenylamine. These can be removed by mercuration or H2/Raney nickel. You can react the amine with an electron-deficient aryl chloride, displacing chloride and generating an electron-deficient aniline derivative that may lose one proton but not react further. Picryl chloride and chloropentafluorobenzene can react with amines to give anilines, and there are probably cutting-edge protecting groups based on these.

I would recommend against using MOM and MEM groups because under basic conditions these might result in a more reactive imine forming that can react with n-BuLi. These protecting groups are not suited to amines. They work well with alcohol protection, where the products are acetals of formaldehyde. If you are interested in that kind of group, think about exploring turning your primary amine into a derivative of thiamorpholine [a two-step but very clean reaction sequence avoiding the use of bis(2-chloroethyl)sulfide is treatment with 2,2'-thiodiacetic acid using a coupling reagent strong enough to form the cyclic imide, followed by reduction by borane-dimethylsulfide to the thiamorpholine group]. Removal can be the same as removing other sulfur-based groups (H2/Raney nickel, which leaves behind a diethylamino group) or oxidation (by MCPBA/bicarbonate or H2O2 etc.) in acetonitrile followed by aqueous base like 5%-10% potassium carbonate (the end product is the primary amine and 2,2'-sulfonyldiethanol, a water-soluble diol byproduct). I did the latter and it is a high-yielding, very mild protection and deprotection in which BOC-protecting group, acetals, esters, nitro groups, and conjugated C=C-C=O survive, but isolated C=C groups, carboxylic acid, aldehyde and ketones don't. I don't recall the literature references I used, off-hand, sorry. I would need access to a literature searching tool better than Google Scholar, but I don't have that. However, it's an example of "seek and you will find" that worked for my particular synthesis of a differentially protected non-natural amino acid, 2,4-diaminobutanoic acid, sometime around the late 1990's. So keep seeking. Best wishes.

You're welcome Roma. All the best.

Dear all, the size of the stirring bar influence essentially two factors, i.e., shear degree or level and heat conduction and dissipation. These two factors are in direct influence on all NPs features : growth kinetics, shape, size and its distribution. The effect may not be monotonically scaled, but for sure it is a compromise between these factors. My Regards

Hi David ,

You may use the web tool to calculate

Kamran Nasir Yes, you are right, as long as you compare it to other spectra that are recorded under the same conditions (same angle of incidence, ATR crystal and polarization state) there should be no problem.

Heavy metal pollution will always be relevant. However, I think that further studies on remediation strategies will be a plus.

Adding to Dr. Hanson's setup, if you want the gaseous product to be free (or mostly free) of reactant gas, you can connect multiple gas dispersion tube in parallel so that all the reactant gas is converted to product. Reactant gas to inlet of gas dispersion tube containing liquid reagent, outlet connected to the inlet of 2nd gas dispersion tube containing more liquid reagent, outlet of the 2nd gas dispersion tube connected to the inlet of 3rd, if required, and so on.. You can collect the product gas from the last outlet.

In principle it is an easy calculation but in practice it depends heavily on the substances and their interaction.

https://www.pharmacalculations.com/2016/06/how-to-calculate-density-of-solvent.html

The same concerns will be shared here which means I agree. The supposed standard concept of ethical publishing and research were taught and still in practice. Direct communication to the author/ correspondent is necessary, and in this way, limited access or limited amount of the manuscript maybe shared, both parties protected, and continuum of knowledge is not compromise. Best wishes.@Mahamid

Cashew Nut Shell Liquid - an overview | ScienceDirect Topics

https://www.sciencedirect.com › topics › engineering › ca...

I have figured it out and it's a little less tedious than Christina Ertural's excellent answer. I took the simpler of the two molecules, converted it to SMILES, and then did Build > Insert > SMILES in Avogadro. If I ever need to conserve the coordinates, I'll use the Excel trick. Thanks!

Hello Viraj,

thank you for posting this very interesting technical question on RG. We work in the field of synthetic inorganic chemistry, so that I would not call myself a proven expert in the field of heterogeneous catalysis and transesterification. However, I can suggest to you two very instructive review articles which will certainly help you in your analysis. Thus please have a look at the following references:

Fortunately this paper has been posted by the authors as public full text on RG, so that you can freely download it as pdf file.

The other paper can also be accessed as public full text as it has been published Open Access:

(Please see the attached pdf file)

I hope this helps. Good luck with your work!

Also, kindly check:

just found an article https://retractionwatch.com/2021/12/07/researchers-sound-alarm-on-predatory-rankings/

Dear colleague,

I am sending the following decomposition procedure which we used in the analysis of catalyst samples [1]:

1 g of the catalyst samples was weighed in a 50 ml beaker. 15 ml of

freshly prepared mixture of acids (5 ml conc. HNO3+15 ml conc. HCl)

was added to the sample and the beaker was covered with a watch

glass. The sample was left to stand for 1 h at room temperature in

order to prevent vigorous reactions. After that, the sample was heated

for 6 h on a water bath and allowed to cool down slowly to room

temperature. The content of the beaker was transferred quantitatively

into a 100 ml volumetric flask and filled up to the mark with redistillated

water. The undissolved material (γ-alumina+silicates)

has settled down and the supernatant solution was subjected to

analysis by ICP-AES. The volume of the solid residue is less than 0.4% of

the final volume.

Please, see Ref.[1]

REFERENCES

[1] P. Petrova, S. Velichkov, N. Velitchkova, I. Havezov, N. Daskalova “Problems, possibilities and limitations of inductively coupled plasma atomic emission spectrometry in the determination of platinum, palladium and rhodium in samples with different matrix composition”, Spectrochimica Acta Part B 65 (2010) 130–136, doi:10.1016/j.sab.2009.12.005

With kind regards, N.Daskalova

The following useful RG link is also very useful:

Dear Manel Taferguennit in this context, please have a look at the following instructive presentation:

The presentation is freely available on the internet. It might also be worth reading the answers given to the following closely related question which has been asked earlier on RG:

(6 answers)

Good luck with your work!

Kindly see also the following useful link: https://www.wired.com/story/how-to-make-hand-sanitizer/

Dear Viraj,

many thanks for sharing this very interesting technical question with the RG community. Did you follow a published procedure? Perhaps I did not fully understand your question. However, after the acidification step, you don't have any potassium present in your mixture. Thus at this stage no K₃PO₄ precipitate can form. This can only form after separation of the different phases and neutralizing the purified glycerol with KOH. Please have a look at the following published procedure (citation):

"As the crude glycerol received is solid at room temperature, around 200 g of the crude glycerol was melted at 55 °C in a 500 ml beaker placed on a magnetic hot plate. The molten crude glycerol under gentle stirring was acidified with different acids (sulfuric acid, hydrochloric acid, and phosphoric acid, respectively) to a desired pH level and was kept for a sufficiently long time to allow the formation of three separate layers. The top layer is fatty acid phase, the middle one is glycerol rich phase and the bottom one is inorganic slat phase. The bottom phase was separated by simple decantation. The fatty acid-rich top phase was separated from the glycerol-rich phase by using a separator funnel. The extracted glycerol was neutralized using 12 M KOH solution followed by evaporation of water at 110 °C for 2 h and filtration to remove the precipitated salt."

As you can see, you need to separate the phases, neutralize with KOH, and then remove the remaining water by evaporation. Only after these steps have been carried out, the potassium phosphate salt will precipitate.

This is the article from which the cited procedure was taken:

I hope this helps. Good luck with your work!

It depends on the type of crude oil you are using and the type of other reactants

After the last reaction analysis is complete. Dilute it with methanol and wash it, centrifuge again, the catalyst will be better recovered.

Dear Jhune Dominique Peralta Galang thank you for sharing this very interesting chemical question with the RG community. I'm not really a specialist in this chemistry. However, I can suggest to you the following potentially useful review article which might help you in your analysis:

Fortunately this article has been posted by the authors as public full text on RG. Thus you can freely download it as pdf file. Moreover, most of the authors of this paper have RG profiles. You can easily contact the corresponding author via RG and discuss your question directly with him as he is a proven expert in the field.

I hope this helps. Good luck with your work and best wishes, Frank Edelmann

Dear Dr Katta Venkateswarlu,

Interesting topic. I think these documents (in attached) may actually interest you since the book summarizes the groundbreaking advancements in organic chemistry made during the19th century while the review article those of twenty-first century.

Best wishes,

Sabri

Dear Viraj Miyuranga . See the following useful link: http://www.bioline.org.br/pdf?st11020

Please refer this article which will be a help

The reagent SNAP, are prepared by mixing solutions of N-acetyl-penicillamine, with equimolar NaNO2 in 0.5 N HCl. The reaction is typically complete within 1 min; for reasons of stability, the solution is neutralized by addition of NaOH immediately before addition to the protein solution. source: Nitric Oxide Synthase: Characterization and Functional Analysis

Ying-Yi Zhang, Joseph Loscalzo,

See attached article

contact with even a small amount can cause an allergic reaction with symptoms such as skin redness, itching, rash and swelling.

Hi Hector,

May be you can do it your self using SPE protocol in this paper.

You have an overview of the method recovery and matrix effect.

I hope this helps!

Dear Dr Dariusz Prokopowicz,

Very interesting topic. In my opinion, bioplastic may a more realistic / alternative solution since the actual research works are focusing on the possibility to elaborate bioplastic from renewable resources, which will have the characteristics to be biodegradable / recyclable.

Here's in attached a recent article treating the economical potential of bioplastic.

Best wishes,

Sabri

Hello, here is the spreadsheet for CIPW calculation.

Best regards, Zilong

Your "conversion factor" is actually a "confusion factor". Let's go back to basics here:

You can check your calculations by using the Mg/MgCl2 ratio e.g. 24.3/95.2 = 25.5% (of the 0.095g will be 0.0242 g of Mg²⁺). (Is this where you got confused?)

Similarly, 24.3/203.3 = 11.9% (of the hydrated 0.203 g is ... 0.0242 g of Mg²⁺).

This should be found and probably explained better than what I have written in most(!) undergraduate textbooks.

Dear Dr Antonia Mauch . See the following useful RG link:

Dear Stanislaus O. Okwundu thank you for sharing this very interesting chemical question with the RG community. As a synthetic inorganic chemistry I absolutely not an expert in this area of research. However, I at least found two literature references which at least come close to answering your question in part. Both describe the dehydrogention of cyclohexylamine under formation of aromatic amines. Please have a look at these articles:

and

The second paper is even freely available as public full text. You can find and access other related articles by searching the "Publications" section of RG for the term "dehydrogenative aromatization":

Other articles are found when searching for terms like "acceptorless dehydrogenative aromatization". When searching for literature references, I think you should better avoid the term "uncompromising" as in your original question. This word seems to be rather unusual in this context.

I hope this helps. Good luck with your work and best wishes, Frank Edelmann

I know about a free tool with the name ACD ChemSketch which can be used to generate 2D and 3D chemical structures.

I have a created a course for learning this tool. Check it out at https://drravirawat.wordpress.com/the-art-of-writing-chemistry-in-electronic-notebooks/

This method has no benefit that I can see over the usual method of measuring the absorbance at a single wavelength and applying Beer's Law. It is also unrealistic in that absorbance spectra typical lack linear parts, except as approximations over short wavelength ranges. Nevertheless, below I examine the proposed method in detail.

Consider the absorption spectrum of a substance S in a dilute solution, such that Beer's Law pertains and the absorbance at any wavelength is directly proportional to the concentration. The constant of proportionality is called the extinction coefficient.

For the slope measurement, choose any 2 wavelengths (lambda 1 and lambda 2) at which the solution has a non-zero absorbance. The difference betwen the 2 wavelengths is Delta lambda. Measure the absorbances (A) of the solution at each wavelength: A₁ and A₂. If you draw a line between these two points on the spectrum, as for any two points in a plane, you can measure the slope of the line as (A₂-A₁)/(Delta lambda).

Now consider a solution of twice the concentration as before. Its absorbance values at the same two wavelengths will be 2A₁ and 2A₂, because for dilute solutions the absorbance is directly proportional to the concentration, according to Beer's Law. The slope of the line between the two points on the spectrum of this solution will be (2A₂-2A₁)/(Delta lambda) = 2(A₂-A₁)/(Delta lambda).

Thus, the slope of the line between the two points increases in direct proportion to the concentration. The result of the comparison of the spectra by this method is that you have determined the ratio between the concentrations of the 2 solutions, but not the actual concentrations. To get the actual concentrations, you either need to know the concentration of one of them to begin with, or to know the extinction coefficients at the two wavelengths.

Notice, by the way, that this calculation did not require that the two selected points on the spectrum lie along a linear portion of the spectrum. They could be anywhere on the spectrum. More to the point, the calculation achieved the same result as a measurement made at a single wavelength.

Nalidixic acid - A NSAID grs of drugs or pain killer .REF : en.wikipedia.org ( Image Source ) .

The subject of specialisations does not depend on the feature income rather your subject if interest . Organic chemistry has too much scopes as a synthetic( R&D) chemist in multinational pharmaceutical houses like Chem biotech , Pfizer , DRL labs etc etc. Even in post doc level abroad from India very high scope in organic nano synthesis like CNT . So scope of income is naturally very high in organic chemistry indeed . But in analytical chemistry the scope is narrow compared to organic chemistry . Since analytical and quality control laboratories are also guided by organic chemists / phyto chemists / petrochemicals for mainly UV-Visible spectrophotometric analysis / Chromatography like GC , HPLC , HPTLC , GC-Mass spectrophotometer and fluroscence spectroscopy .Yes analyical chemists are useful in effluent treatment / waste water analysis as well as drinking water analysis of trace heavy metals like Cu , Cd, As , Pb , Hg ( II , I ) by AAS ( Atomic abs Spectrophotometry ) AES ( Atomic emission spectrophotometry. In drinking / waste water lab there are so many important analytical parameters like B.O.D , C.O.D , D.O , pH , TDS , TSS and limit tests for heavy metals in trace metals .

Hi, this paper is useful for you about this question:

The science fiction book Jurassic Park and the movies based on it are about recreating dinosaurs by extracting their DNA from the guts of dinosaur-biting insects trapped in amber.

DNA is not sufficiently stable to survive for the necessary 65 million years or longer since dinosaurs roamed the Earth, so dinosaur DNA is not available. What you would do with it, if you could get it, in order to recreate dinosaurs is another issue.

The oldest DNA ever recovered was recently reported from 1.2 million year old mammoth teeth in Siberia.

It has been seriously proposed to recreate mammoths, which went extinct several thousand years ago. Mammoth DNA is available from animals preserved in permafrost.