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  • Esmaeel Safijahanshahi added an answer in ANSYS:
    How do I block an hemisphere in ICEM CFD and get a good quality mesh?

    I am doing in cylinder flow analysis of piston bowl.

    Esmaeel Safijahanshahi · Shahid Bahonar University of Kerman

    Dear Nick Juana

    Here is a pdf file that I think it should be useful.

  • Helmut Ritter added an answer in EDC:
    How can I get maximum yield of PEG-PLGA diblock copolymer using EDC/NHS coupling reaction?

    I have tried synthesizing PEG-PLGA diblock copolymer using traditional EDC/NHS reaction. The problem here is the yield of the final product. It was around 20%. What could be the reason for this? Kindly suggest how to overcome this problem. 

    P.S.: I have used PLGA-COOH and mPEG-NH2 for the reaction. activated PLGA was precipitated with ice-cold ether and PEG-PLGA was precipitated with ice-cold methanol. 

    Helmut Ritter · Heinrich-Heine-Universität Düsseldorf

    Your problem is quite different.: since the polyester is highly unstable towards hydrolysis and amino lysis the yield must be low with an carbodiimid ! 

    Thus, I recommend simply to mix both polymers and some base, eg triethylamine, to deprotonate the amino end group and keep it without solvent at elevated temperature .

    then you must obtain statistically composed block copolymers in quantitative yield.

    good luck 

  • Esmaeel Safijahanshahi added an answer in ANSYS:
    Its all about the meshing in ansys?

    Can we mesh a line non-uniformly, I mean If a line length is 100 mm, can we mesh it with a mesh length as for example 25mm, 20mm, 10mm , 20mm, 25mm ???

    Esmaeel Safijahanshahi · Shahid Bahonar University of Kerman

    Dear Sandip Adhikari 

    Here is a PDF file about mesh generation that I think it should be useful.

  • Akira Kanda added an answer in Space Time:
    Do objects move in relation to space-time in GR?

    Generally sympathetic to Carlo Rovelli's pronounced "relationalism" regarding space and time, I still find some of what he says about this puzzling. This question seeks clarification. He argues, in his paper "Localization in QFT," (in Cao ed. Conceptual Foundations of Quantum Field Theory, 1999, p. 215, that "General relativity describes the relative motion of dynamical entities (fields, fluids, particles, planets, stars, galaxies) in relation to one another." This seems true enough. But this is supported by the idea that space-time itself in GR is a "dynamical object," which curves or changes by relation to mass and energy present. But that does not seem a reason to hold that objects do not move in relation to space-time in GR. Instead, it seems that the gravitation field (which determines space- time) is one of the things in relation to which objects move, and consequently that objects move in relation to space-time in GR. In spite of that, Rovelli can be found to say, on the same page, that "Objects do not move in respect to space-time, nor with respect to anything external: they move in relation to one another." Is it inconsistent to think that if objects move in relation to one another, then they move in relation to the encompassing space-time?   

    Akira Kanda · University of Toronto

    So, Physicists, now your community once politically intimidated true scientists who rightly questioned them  is reduced to a bunch of coward folks who run away from criticisms and questions using juvenile elementary school kids level reactions and putting thumb down cowardly without presenting any material counter argument.

  • Could anyone advise me if it is always better to incorporate some control variables into the research model to gain more reliable results?

    In marketing area, I have seen some studies using control variables in their research model while others did not. Is it necessary and better to incorporate some control variables into the research model?

    Rahul Pratap Singh Kaurav · Prestige Institute Of Management

    Hello Mai, In my opinion it is always better to use control variables. 

  • Alison Pittman asked a question in Codes of Ethics:
    Where to find articles that relate to leadership role in group work ?

    Can anyone suggest a good cite to find journal article that pertain to working with groups in a leadership position social work, working with culturally and diverse groups, the nasw code of ethics when working with groups?

  • Joshua D Chandler added an answer in GSEA:
    Can GSEA (Gene Set Enrichment Analysis) be applied to proteomics dataset?

    Most of proteomic researchers abstract the biological significance of their proteomic data by examine the up/down-regulated proteins first then perform functional enrichment analysis on these proteins to see which functions are "enriched" in those differential proteins. Is there a software tool for proteomic researchers not only look at the differential proteins, but instead view the abundance of proteins of a specific function as a whole, then to test if the abundance changes were signicantly different compared with random dataset.

    I looked up the gene set enrichment analysis, but it was designed more for array data than proteomic data. We had a very pool connection with the EnrichNet, however.

    Joshua D Chandler · Emory University

    You could use pre-ranked GSEA with the respective gene names of your proteins (e.g., TXNRD1 instead of TrxR1) and a t statistic or another ranking score and it should work just fine as long as you use gene names that. I believe the row (gene) names have to be unique, so you could not submit multiple peptides of the same protein as different data points to be combined by the algorithm or processed separately. As for using the standard GSEA workflow, that would be impossible.

    If you end up finding a workflow you like, please share it.

  • Which online tool is better and cheaper (free would be the best) for master thesis survey?

    I have 20 questions and Likert Scale for Rating questionnaire. Later on I would like to analyze results in SPSS. Thank you for your help!!!

    Rahul Pratap Singh Kaurav · Prestige Institute Of Management

    Hello Nina, Google forms create attractive documents to share.

  • Eric Baird added an answer in Special Relativity:
    Who rewrote General Relativity?

    Einstein's General Theory of Relativity seems to have “crashed” as a scientific theory in about ~1960, and to have been "rebooted" some time in the early 1960s as "modern GR" with a different set of definitions and rules that differ from those laid out by Einstein.

    I'd like to know who originally made those "redesign" decisions, how the community consensus was reached, and where the changes (and their justifications) are documented.

    Background: Einstein had based his theory on the General Principle of Relativity: the idea that all motion was relative, and that even “absolute” motions such as rotations and accelerations could successfully be “relativised” if bodies showing those relative motions could be associated with suitable gravitational/distortional effects. This was an idea previously proposed by Ernst Mach, and Einstein described his general theory as being the theoretical embodiment of Mach's principle.

    For derivational convenience, Einstein also initially assumed that the theory should reduce to the physics of special relativity over small regions.

    However, the publication of the Harwell group's 1960 paper on centrifuge redshifts (Phys. Rev. Lett. 4, 165 (1960) ) apparently triggered a controversy within the community, and an appreciation that a literal application of the GPoR seemed to lead to results that were geometrically incompatible with special relativity – the consequence of the GPoR being treated as a “law” then seemed to be not only the loss of Einstein's 1905 "Special" theory, but also the loss of the 1916 "General" theory that had been partly built upon it (Schild, Am. J. Phys. 28, 778 (1960) ).

    We were facing the unpalatable prospect of a major rewrite of theoretical physics, and although a rederivation of GR to avoid its dependency on SR had already been suggested by Einstein back in 1950 (SciAm 182, 4, 13-17), we found it easier to modify the rules of general relativity to allow the GPoR to be suspended in cases where it seemed to clash with other parts of the 1916 theory. In effect, we accepted that the original “SR+GPoR” structure was logically inconsistent, but maintained order by redefining SR's position in GR's definitional hierarchy to one in which GR could not disagree with SR “by definition”, and establishing a "failure etiquette" ("If the GPoR conflicts with SR, keep SR and suspend the GPoR").

    This change seems to have happened with minimal recorded public comment or discussion. Although Schild's paper mentions discussions and "a certain lack of unanimity" in the community as to how to proceed (before he presents the "modern GR" position as unavoidable) Schild doesn't indicate who participated in those discussions.

    I'd like to know who was on the committee, who voted for or against the change, and whether any of those concerned published anything on the nature of the 1960 crisis and the chosen response. Does anyone here remember it or have direct personal experience of what happened? Is there any historical record of the episode other than the rather skimpy Schild paper? Did anyone else publish the arguments for modifying Einstein's theory, or the contemporary arguments why GR1916 couldn't continue to be used in its pre-1960 form?

    Any references to additional contemporary material would be very, very welcome.

    Charles: " Eric, local is local enough that the difference between curved and flat is not detectable at the limit of experimental accuracy. "

    But Charles, you do understand the problem with the usual geometrical proof of a reduction to special relativity ... that as a mathematical proof, it holds (unphysically) even in a universe in which the physics of curved spacetime does NOT reduce to the physics of SR. Logically, the possibility exists that the "reduction to SR" result can appear to be mathematically proven, while still being physically wrong. 

    Charles: " A curved spacetime is the envelope of many flat spacetime segments at the level of experimental accuracy. "

    if you're viewing this on a computer screen, your spellchecker understands individual letters, and sequences of letters that form words, and your grammar-checker understands sequences of words that form basic sentence structures. it understands basic pre-programmed rules of grammar. 

    If you zoom in far enough, you'll find that individual letters consist of solid black or white (or grey) rectangular pixels. If you blow one of those pixels up to cover the full screen, the interior characteristics of the pixel do not contain the rules of sentence structure, or even any information about what letter the pixel might have been part of.  It can contain no identifiable letters or words or sentences, since all that information only exists at a higher level of organisation.

    In a Cliffordian universe, to talk about curved spacetime physics reducing to the physics of flat spacetime over very small regions is like someone picking up a poetry book and saying that since they can prove that the entire book is effectively composed of tiny solid black and white regions, that the interior properties of those solid regions must define the basic rules of (simple) poetry. They don't. They represent the limit at which poetry and language no longer exist.

    In a Cliffordian description, if we do choose to break a curved-spacetime description into an approximated description of a surface consisting of tiled facets, then inertial physics doesn't exist within the facets, it exists between the facets – if all the curvature is moved to a network of edges, then it's the "wireframe" skeleton created by the network of edges that approximates the physics.


    I think that if we want to present the geometrical reduction to SR as being more than a mathematical whimsy with no physical content, we probably need to do one of two things:

    1. Define our mainstream general theory of relativity as reducing to SR physics by definition, by explicitly making an assumed physical reduction to SR one of the theory's postulates.  if we do that, then the resulting theory does obviously reduce to SR physics by definition ... but the postulate is then open to having its correctness questioned.
      We'd also the lose the ability to claim that our current theory is the only conceivable general theory of relativity, because the explicit existence of the "SR reduction" postulate would invite discussion about whether the postulate was valid, and what an alternative general theory would look like that didn't contain it. This discussion doesn't seem to be considered desirable.
    2. Find a way to show that a Clifford universe doesn't work, or that our own universe isn't Cliffordian. Nobody seems to have done this.

    As scientists, I think we should be reacting to this situation either by openly acknowledging the apparent diversity of options (1), or by showing that the alternative option(s) either don't work or are somehow inferior (2). So far, the community doesn't seem to have shown much willingness to do either of these two things.

  • Arthur Scott asked a question in Frustration:
    Does anyone have any research which validates the use of Art Work and Counseling Children. I am finishing my Masters in Clinical Mental Health Coun?

    my email address is 


    I am frustrated in that is seems there is very little research to be found which validates the work of Carl Jung and the use of Art Work as Therapy / Treatment.

    including the use of Mandala's.

  • Ashkan Meamri added an answer in Swarm Intelligence:
    Is there any book you recommend for swarm intelligence?

    A textbook or classic are both fine. It is much better if it has pedagogical approach with a focus on optimization and algorithms implementation

    Ashkan Meamri · Universiti Teknologi Malaysia

    I recommend you to see "Swarm Intelligence and Bio-Inspired Computation" By Xin-She Yang

  • How can I simulate a pounding phenomenon between two adjacent buildings?

    I'm trying to avoid pounding between two adjacent buildings (10 and 5 floors height, 10 and 10 floors height), and I'm asking how to create a pounding. before avoiding it. we have to create it. supposing that the the two buildings are submitted to the same earthquake record. how to make those two building shaking in different modes? and how to create a dephasing (phase shift) between them, which is the mean cause of pounding or hammering?

    Nikos Pnevmatikos · Technological Educational Institute of Athens

    Dear Mahdi Abdeddaim

    You can see the paper  that i sent you may it helps

    Best regards


  • Aswini Kumar Giri added an answer in QSAR Studies:
    Can anyone suggest me some free online tools for QSAR study of lead compounds?

    tools for QSAR analysis.

    Aswini Kumar Giri · The University of Arizona

    Hi Mahadev,

    Go through the website http://www.qsartoolbox.org/. You might find it helpful for you.


  • What is the influence of the day care centres on the parental involvement during the early childhood?

    There are different types of day care centres formal and informal, but of which all require parents to be involved in their children upbringing. But how does this influence the parents/ caregivers' involvement from ages of 0-5 years?

    Gisela Wajskop · Ontario Institute for Studies in Education/Uoft + GW Assessoria Pedagógica Brazil

    This is a good question for a research. In Brazil we have a idealisation about this relationship but I'm not sure that in general, speciality in Public Day care Centres, the influence is positive. Most of Day Care Centres don't care about the cultural trademarks of raising children.

  • Julio C. Guerra Justino added an answer in MPPT:
    How can I size heat-sinks?

    I'm developing a 1kW hardware prototype of a DC Nanogrid. The standalone DC nanogrid is supplied by a 1kW PV array and a 60V, 150 A battery bank. I'm not using any soft switching techniques.

    In total there will be three converters.

    1) Boost converter- For MPPT. Pmax= 1kW

    2) Buck converter (for the load) - Pmax= 1kW. IL,max= 41A.

    3) Bi-directional converter- Pmax= 720W, Ibat,max= 12A.

    How do I go about sizing the heat-sink ? I'm attaching a block diagram of my system as well.

    Julio C. Guerra Justino · Centro Federal de Educação Tecnológica de Minas Gerais

    I suggest using Psim. I like a lot.

  • Which is the best tool to analyze ADME of drugs?

    I have 50+ drugs after virtual screening, is there a tool (preferably free) which I can use to analyze ADME of all these drugs at time.

    Aswini Kumar Giri · The University of Arizona

    Hi Thirumal,

    Two persons have already addressed your question. I hope that will help you.

    I wanted to correct one thing in your question. You cannot have drugs after virtual screening. As long long as any molecule is not used clinically, it can not be called as a drug. I would suggest to use the terminologies like drug candidate or potential drug candidate etc.

    Have fun in searching ADME properties of your drug candidates.

  • Abeyou Wale Worqlul added an answer in DIVA GIS:
    How can I extract environment data from GIS layer for locality point?

    I downloaded bioclimatic variables from WorldClim.

    I want to extract environment data for random or specific locality point.

    Can anyone guide me?

    Thanks in advance.

    Abeyou Wale Worqlul · Bahir Dar University

    Hi Yue Li,

    I have attached you a youtube video of a short tutorial: 


  • Zuhaib Haider added an answer in Laser Ablation:
    What is the effect of magnetic field on laser ablation?

    Is the presence of magnetic field ,affect the laser ablation

    Zuhaib Haider · Universiti Teknologi Malaysia

    Mr. Ghaleb,

    Magnetic field has effect on dynamics of laser induced plasma (charge distribution and confinement) instead of laser ablation.

  • Dony Saputra added an answer in Workforce:
    Exchanging educational data: Are there any (emerging) international standards?

    Problem: More and more countries are getting involved in the globalized world, partly by strengthening such transnational communities as the European Union and the AEC (ASEAN Economic Comunity). The free movement of the workforce and of students is a fact in this regard. Besides the need for comparable transcripts there is also the need for the secure exchange of such data between national authorities. 

    What are current activities in setting up data international exchange standards (such as EDIFACT (Electronic Data Interchange For Administration, Commerce and Transport, United Nations) for educational institutions?

    Dony Saputra · Binus University

    dear prof i think you need to clarify which data that going to be exchange is it academicaly related with amount of student lecturer and operational activity or data related to teaching learning activity using lms.

    As far as i know if its data exchange have to be in same formated data or there are a generalize software that able to merge all type of data such as xml for web based related data or xbrl for finance and accounting.

    Maybe we can do joint research on creating this and its framework.

  • Paras Jain added an answer in Extracts:
    I would like to isolate the pure compounds from crude extract of my plant sample, how?

    please suggest me methadology

    Paras Jain · Ranchi University

    Bioactive phytochemicals

    like Bhilawanol (it is a phenolic compounds)

  • Can anyone share the protocol of flowcytometric Cell proliferation analysis using BrdU-anti-BrdU?

    I am working on detection  of lymphocyte proliferation assay using Brdu-anti-Brdu by flowcytometry, but not successful yet and need help

    Muralidharan Jayaraman · University of Oklahoma Health Sciences Center

    I agree with Eugen, EdU does work better! Good luck!

  • Are there any clear examples of DNA convergence?

    Alan Wilson and colleagues in 1987 famously showed that the amino acid sequence of lysozyme had converged to be the same in the cow and in a leaf-eating monkey, so that molecular phylogeny based on this protein would have erroneously placed these unrelated, phytophagous, mammals on the same branch of the tree. Since DNA evolution is actually less constrained than amino acid sequence (because of “third base wobble etc”), one might expect that there are now many examples of DNA convergence as well.

    Jack D Pettigrew · University of Queensland 

    1. One general example involves the fact that guanine is more sensitive to oxidation than the other three bases. 8-oxoguanine, the product of its oxidation, is read by error-correcting enzymes as adenine, leading to an inexorable AT bias in mammalian DNA, that is greatest in mammals that have the highest metabolism.

    2. The slime mould, Dictyostelium, has a large AT bias which results in its alignment with procaryotes that have a similar bias. Without human help, computers align the slime mould DNA with the bacterial DNA. This erroneous pairing disappears if translated codons are used for phylogeny instead of DNA, when the slime mould moves a number of nodes up the tree of lie to join the fungi.

    3. Both microbats and megabats have dramatically enlarged immune systems, an evolutionary response that is thought to relate to an increased need to repair damage to cells caused by the very high level of ROS (Reactive Oxygen Species) that are produced in powered flight when metabolic rate increases by 20X. This increased immunological competence is probably responsible for the tolerance of both kinds of bats to many kinds of virus that are lethal to humans such as Ebola, Marburg, Nypa, Hendra, Rabies, Sars, Mers, etc Molecular dissection of microbat and megabat immune systems shows that they have been enlarged by completely separate mechanisms, a striking example of molecular convergence at the DNA level.

  • Md.Azizul Moqsud added an answer in Biogas:
    Why biogas plant is not widely used for small electric network?

    Biogas is mostly used for cooking purpose and it also generate electricity but doubt is why it is not used for long run and what are the problems associated with generator. Why it is not successful at all.

    Md.Azizul Moqsud · Yamaguchi University

    I think the most important problem is the supply of organic waste which will be the raw materials for biogas production for small electric network. People like to use directly as burning and getting heat for cooking purpose rather than to generate the electricity. Another thing, if the biogas content moisture or hydrogen sulphide that reduce the efficiency of electricity generation.So its a better option to burn and cook foods directly.

  • Mathan Sambu asked a question in Air Flow:
    Ist possible get Air Flow Resistivity for acousics material using any modelling software?

    i seeking a way to get air flow resistivity value to predict my acoustic materials`s alpha value. Ist got any software that using finite element or modelling method to identify it? what software can be use and what are exact input value are requires?

  • Any tips for how to maintain Hypoxic condition inside an Normal CO2 incubator??

    To determine the Hypoxic induced protein expression in cancer cells, How to maintain Hypoxic environment inside a normal CO2 incubator.??

    Muralidharan Jayaraman · University of Oklahoma Health Sciences Center

    If you want to buy a small device that will create hypoxic environment, follow this link http://www.brincubator.com/hypoxiachamber.htm. You may want to look up similar devices that may be available locally. Good luck!

  • Is there any model of undergraduate thesis for international business management programs?

    Me and My colleagues are given task from the university to create a undergraduate thesis topic for our International Business management Program. But we have difficulties in finding references , models and example for the thesis. Because as far as we search on search engine, all we can find is Master thesis references.

    Can you help us to give idea on what recent trends or excellent topic that related to international business management Program?

    Dony Saputra · Binus University

    Dear Prof. Krishnan,ian and jacic thank you for your comment, can you give me example of bachelor thesis or any references for this international business management program.

    Dear prof Jacic, actually its not diploma but bachelor degree as there will be supervisor but we as faculty member from the program at least give an example of the thesis as an overview for the students.

  • Mafatikhul Ilmi asked a question in Buffer:
    How can I get data from I/O TMS32C6713 ?

    I get talkthrough code from cepstrum.co.jp to access I/O tms32c6713 but I get a problem when I give buffer proccess in input data, the problem is sound doesn't clear enough when I try to playback the signal.

  • What is the easiest way to create XML format files with the sequences and the tree in the same file?

    I want to run an analysis and have to use XML-based file format which I have never done before. The guide tree and the sequences have to be in the same file. Does anybody know a program which can generate such files easily?

    Teofil Nakov · University of Arkansas

    Some R packages for phylogenetic analyses would have this functionality. For example: http://www.phytools.org/static.help/export.as.xml.html