ResearchGate Q&A lets scientists and researchers exchange questions and answers relating to their research expertise, including areas such as techniques and methodologies.

Browse by research topic to find out what others in your field are discussing.

Browse Topics

  • What is significance of dynamic order of the synchronous machine?

    what is significance of dynamic order of the synchronous machine?

    Christian E. Jacob · Max Planck Institute for Plasma Physics

    Dear  Vipin, please lock my patent (only in German) under

  • Can I estimate the fatigue life of a HAWT blade without damaging it?

    I want to apply cyclic load on the blade to inspect it under fatigue loading. 

    I want to save the blade and I do not want to causes failure to it. 

    I'm looking for a methodology that can help me in estimating the number of cycles to failure by certain applied cycles. 

  • Does “spin” imply physical rotation?

    The “spin” of an electron or other fundamental particle is often described as “intrinsic angular momentum”. This terminology is required because a point particle or Planck length vibrating string cannot possess ½ ħ of angular momentum. Larger objects such as molecules or electrons in atomic orbitals possess quantized angular momentum which can be demonstrated to involve physical rotation. For example, a carbon monoxide molecule in a vacuum can only rotate at integer multiples of 115 GHz which is integer multiples of ½ ħ. Therefore, do you believe that fundamental particles have a physical angular momentum that is currently not understood? Alternatively, is "intrinsic angular momentum" an accurate description of spin because it is a quantum mechanical property that does not involve physical rotation?

    Anatolij K. Prykarpatski · AGH University of Science and Technology in Kraków


    OK, well - understood.


  • Sonal Soi added an answer in Cancer:
    What would you add or change for a complete list of the hallmarks of cancer?

    The concepts published on the hallmarks of cancer (Hanahan D, Weinberg RA, The hallmarks of cancer Cell. 2000 Jan 7;100(1):57-70) and its update (Hanahan D, Weinberg RA, Hallmarks of cancer: the next generation Cell. 2011 Mar 4;144(5):646-74. doi: 10.1016/j.cell.2011.02.013) have been very influential in forming our ideas about the nature of cancer and reasonable approaches to improved interventions. Do these published hallmarks completely capture current ideas or would you add or change them from your results and understanding?

    Sonal Soi · ITS-CDSR

    Cancer cell demonstrate an acidification of extracellular pH and alkalinisation of intracellular pH such A - Reversed pH gradient could be an emerging Hallmark....

  • Alireza Salehi Nejad added an answer in Execution:
    How significant is the death penalty deterrent effect when those on death row can enjoy their lives for at least 10 years before they are executed?

    After the abolition of the death penalty in some countries, did crime rate increase or decrease in those countries? Which better serves justice: the deterrent effect -if any- of the death penalty or the risk of executing a wrongfully convicted human being?

    Alireza Salehi Nejad · University of Tehran

    Hi Aceil,

    Death penalty has cultural, religious and political dimensions. Generally, death penalty is practiced for crime prevention, justify, and even symbolizing an act.

    Somehow, over history, death penalty has served its purpose well, however, there are various discussions about it's humanity and moral aspects. Capital punishment was practiced in France from the Middle Ages until 1977.

    Many happen to believe that every now and then a criminal must be executed to prevent further corruption.

    Yet again, this is not applicable for desperate people or criminals. For instance in the 18th century France, whether before revolution or The Reign of Terror, the act of execution by guillotine was prevalent, however, it failed to prevent the act of crime.

    Therefore, a phenomenological or even analytic approach towards capital punishment, in order to understand the toots of the crime, its prevalence and public view, are necessary before criticizing the act and form of the punishment.

  • Asghar moradi kashkuli added an answer in Blasting:
    Can we use Volterra functional method to predict vibrations induced by rock blasting?

    Volterra series is based on non linear method considering input parameters to evaluate an output. Neither rock mass is continuum nor is it a homogeneous material and if we want to predict vibration due to rock blasting we need to take into account various effective parameters including joint sets and two major influencing parameters i.e charge weight per delay and distance. 

    I want to know if we can use Volterra Functional Method for our problem.

    Asghar moradi kashkuli · Isfahan University of Technology

    I personally suggest machine based-learning network solution Like ANN (artificial neural network) ,you can input all data mentioned above without concern about knowing relation between them.You can use MatLab Anfis tool or Ann tools for your problem.

  • Any links to research/resources addressing the psychological impact of being hacked?

    I am looking for reference materials that specifically relate to the impact on those being hacked of ongoing hacking. Has anyone seen anything with particular reference to this?

    Any guidance will be appreciated.

  • Petr Michálek added an answer in FID:
    Flame ionisation detector baseline shifting?

    We have four FIDs + electrometers EL 980 for on-line concentration measuring. There is a problem, that the zero baseline on FID1 is shifting and in some time (ca. minutes to hour) it reaches the maximum value, but without any sample input. After applying the autozero function, the baseline moves down on some value, but in some time it starts to shift again. Is this a problem of the FID itself or the electrometer module?

    Petr Michálek · Výzkumný a zkušební letecký ústav, a.s.

    Ok, I can try to increase the FID temperature above 100 °C, but I dont know the maximum temperature that the heating wire can stand. I do not have documentation for the FIDs. Thank you all for your advices.

  • Can an abelian topological group conatain a projection homomorphism?

    Let G be an abelian topological group. For a fixed element g in G, can we find a projection which is homomorphism, too. I mean a homomorphism like P that P^2=P?

    We can add additional hypothesis to G, like locally compact or connected.

    James F Peters · University of Manitoba

    This is a very interesting question.

    To get started in looking for an answer, check

    W. Ella, Retracts in Category Theory, thesis, University of Mary Washington, 2009:


    See Section 4.2, starting on page 17: Abelian groups (see Theorem 4.5 and Corollary 4.6).

    More to the point, consider projection homomorphisms in

    R.D. Wade, Symmetries of free and right-angled Artin groups, Ph.D. thesis, Oxford University, 2012:


    See Section 3.3, starting on page 46.   See, also, Theorem 5.1 and the comments after Theorem 5.10 (see reference to Charney and Vogtmann [20, 21] in this thesis).  An important part of this thesis is Chapter 3.   In particular, see the amalgamated projection homomorphism in Example 3.7, page 47.   The consequences of Theorem 5.10 are explored in Sect. 5.3.   Great stuff!

  • Which type of labour should attract the highest reward at the workplace?

    Employers are said to be rewarders of three kinds of labour at the workplace: mental, physical and emotional, which of these is most important and deserving of highest reward and why?

    Bright Chidugam Opara · Rivers State Government

    Mental Labour deserve more reward. This is because it takes longer time in training and they also prepare the ground in the workplace, plan or design for the physical work / labour to commence or take place. 

  • Muhammad Sohaib asked a question in Wavelet:
    What is meant by compactly supported wavelet?

    Thanks in advance for your replies.

  • Chandramouli Balasubramanian added an answer in ICH:
    30 cc ICH, 45 yrs alcoholic male, presents with seizure, CT SCAN shows ICH, would you think of operating?

    GCS dropped to 14 following seizure.

    Blood results are pending.

    He is at primary health care ( or a district general hospital) with good ITU and anaesthetic back up.

    I would transfer him to NEURO ITU. More clarifying questions welcome......


    Chandramouli Balasubramanian · National Health Service

    30 minutes since the original admission, Neurosurgeon busy in theater,

    the General ITU consultant calls the NEURO ITU directly and after 5 minutes, the Neurology/stroke doctor accepts the patient and the patient is on the way to the QUARTER NARY NEURO center..the transfer will take 2 hours on the highway.......... an anaesthetist is accompanying the patient

  • Do you know of any MRI image database?

    I would like to do research on MRI images. Can you please suggest some websites from where MRI images can be downloaded. Thanking you. Gautam Talukdar. 

    Parth Shah · VIT University

    Check these links if it helps.

    The best one I would suggest is :http://www.osirix-viewer.com/datasets/


  • Dominique Liger added an answer in Chronic Leukemia:
    What is the best method for laboratory examination of ALL and CML? I means ABL-BCR Fusion?

    I can't get good bands in electrophoresis in nested-PCR, how can I take it?

    Dominique Liger · Université Paris-Sud 11

    I'm afraid I can't help you any more as the article is not available for me either... Sorry.

  • How to remove cyclicity or diurnal behavior from a time-series dataset?

    Hi all, 

    I have a long time-series data with a clear diurnal behavior (cyclicity). Any ideas, publications or works on how to do it? I'm thinking of a Fourier Analysis, but I wonder if anyone has dealt with this problem before?


    Ashraf Afana Afana · Durham University

    Thanks Borislav for the help and for the fantastic documents. 

  • Which type of stability analysis during construction and utilization of underground structures do you prefer?

    Which type of stability analysis (temporary or permanent; static, pseudo-static or seismic) do you prefer during construction and utilization of underground structures? why?


    Asghar moradi kashkuli · Isfahan University of Technology

    It is depend on design factors and structure types.For cavern you should do long term analysis as well as permanent and temporary ..etc analysis ,For structure like metro tunnels seismic analysis is needed too.But you may do temporary analysis for some mining excavations with low life time.

  • Mohamed El Naschie added an answer in Fuzzy:
    Could you use the theory attached for the same problem?

    From Highly Structured E-Infinity Rings and Transfinite Maximally Symmetric Manifolds to the Dark Energy Density of the Cosmos
    DownloadDownload as PDF (Size:2562KB) HTML XML PP. 641-648
    DOI: 10.4236/apm.2014.412073 191 Downloads 240 Views
    Author(s) Leave a comment Mohamed S. El Naschie1*
    1Department of Physics, University of Alexandria, Alexandria, Egypt.
    Starting from well established results in pure mathematics, mainly transfinite set theory, E-infinity algebra over operads, fuzzy manifolds and fuzzy Lie symmetry groups, we construct an exact Weyl scaling for the highly structured E-infinity rings corresponding to E-infinity theory of high energy physics. The final result is an exact expression for the energy density of the cosmos which agrees with previous analysis as well as accurate cosmological measurements and observations, such as COBE, WMAP and Planck. The paper is partially intended as a vivid demonstration of the power of pure mathematics in physics and cosmology.
    Highly Structured Rings, E-Infinity, Loop Spaces, High Energy Physics, Dark Energy, Einstein Relativity, Fractal-Cantorian Spacetime, Nonlinear Dynamics, Quantum Chaos
    Cite this paper
    Naschie, M. (2014) From Highly Structured E-Infinity Rings and Transfinite Maximally Symmetric Manifolds to the Dark Energy Density of the Cosmos. Advances in Pure Mathematics, 4, 641-648. doi: 10.4236/apm.2014.412073.

    Mohamed El Naschie · Alexandria University

    thanks again dear YURI.  I am a student of russian engineering science and later geometry and puer math

  • Stephen Warren added an answer in Space Time:
    Is the flow of time an illusion?
    This has been discussed on ResearchGate in a rather ad hoc way in relation to another question about the absolute immutability of some physical laws but it really deserves its own separate discussion. Below I summarise the arguments in favour.
    The philosophers
    The nature of time has been the subject of discussion by philosophers for 2000 years or more. In the last two decades their views have crystallised. If time flows - (1) How do we know? and (2) How do we measure its speed? In other words - what frame of reference can we use to measure time?
    The philosophers' conclusion is that they would have to invent another time dimension for the purpose but this would then need a third time dimension and so on ad infinitum. This would be absurd and so they conclude that the flow of time is an illusion.
    Relativity, Einstein and Godel (A World Without Time - Palle Yourgrau - Penguin Books, 2005)
    According to the theories of relativity two observers can never agree on the simultaneity of two events that both witness and neither has a "preferred" position that makes one of them correct. This implies that all events already exist and that what we perceive as the flow of time is an illusion.
    Godel showed that rotating universes were consistent with relativity and proved that in them it was possible to travel back in time. He immediately realised that this implied that the past must still exist and that what he called "intuitive time" is therefore an illusion. In 1949 he published a formal proof that time (in our intuitive sense) cannot exist in any universe. This uncomfortable discovery was ignored for nearly half a century but was revived by Julian Barbour in "The End of Time" and is now widely discussed and accepted by many physicists.
    The Laws of Physics
    The fundamental laws of physics describing the forces are time-symmetric.
    What can we say about the time dimension?
    Time still exists but only as a chronological map in which events are located;
    Time is not in any way like the spatial dimensions because:
    It is anisotropic and contains an entropy gradient;
    If we exist in more than one location in any of the spatial dimensions then we will also always then be in different locations in the time dimension;
    Separations in 4 dimensions are extensions of Pythagoras's Theorem but have the form:
    separation = √[x2 + y2 + z2 - (ct)2], which means that time measurements are imaginary (ict) where i=√(-1), as Hawking suggests in "A Brief History of Time".
    Free will is also an illusion
    We live all our lives all the time but every instant feels like "now"
    Time travel is impossible because (a) there is no dimension in which travel is possible, (b) we occupy all the spacetime of our lives and cannot take back to an earlier time our memories of a later time.
    Stephen Warren · Marlow

    Of course you are right Daniele, ans your answer is a timely reminder to scientists of two things:

    1.   Conjectures have no value unless they offer a prediction that can be tested - either by logic or by experiment

    2.  Conviction is every person's right but, however strongly held, does not constitute a proof of its own correctness in he absence of a logical or experimental proof.

  • Amit Mishra added an answer in Molybdenum:
    How much the band gap energy of Molybdenum trioxide is?

    Recently, I started study of MoO3.

    however I couldn't find band gap energy of MoO3, yet.

    Would you tell me website address that I can find band gap of MoO3,

    or you can notice me band gap of MoO3, please.

    thank you.

    Amit Mishra · Thapar University

    greater than 3 eV for alpha MoO3

  • Derek Decarlo added an answer in Cognitive Therapy:
    Is there any research on how cognitive therapy affects speech and language problems in people with aphasia?
    I need some sources to research this topic, to improve aphasia treatment because patients with aphasia after brain injury, besides having impaired speech and language problems, also have cognitive deficits.
    Derek Decarlo · Vidant Medical Center

    Check out the publications of Heather Harris-Wright

  • Demetris Christopoulos added an answer in MATLAB:
    How to plot a real part of a polynomial in MATLAB ?

    How to plot a real part in y-axis and k is in x-axis of a polynomial equation ?

    Say the polynomial:

    x^3 + 0.5*k^2*x^2 + 0.38*x^2 + 0.08*k^4*x + 0.123*k^2*x + 0.03*x + 0.004*k^6 + 0.01*k^4 + 0.05*k^2 + 0.006=0.

    Demetris Christopoulos · National and Kapodistrian University of Athens

    I think that:


    of Hossein's code is OK, see attached plot.

  • Mohit Sharma added an answer in Dental Radiology:
    Is there any study which reported malignant changes in human beings having constantly exposed to only intra oral periapical radiograph?

    So far malignant changes have been found on exposure to higher radiation, but just want to know whether there is any study in which malignant / genetic changes have been found on constant exposure of intra oral periapical radiograph machine?

    Mohit Sharma · I.T.S Centre for Dental Studies & Research

    Australian Dental Journal 2000;45:(3):208-213

  • If I am having a DOE with 4 factors and 3 levels, is it single replication should be enough for my case?


    No of workers
    Frequency of machine breakdown
    WIP levels
    machine altering 

    Adnan Mustafic · University of Tuzla

    Kazim Sari is right, for a Full Factorial Design you will have to do 21 runs for five replications of center point. 1/2 Factorial Design and five replications its about 13 runs. Five replications for corner point for a Full Factorial Design you will need to do 80 runs, and for a 1/2 Factorial Design 40 runs.

  • Is Chalmers' so-called "hard problem" in consciousness real?

    In his 2014 book "Consciousness and the Brain: Deciphering How the Brain Codes Our Thoughts" Stanislas Dehaene wrote "Chalmers, a philosopher of the University of Arizona, is famous for introducing a distinction between the easy and the hard problems. The easy problem of consciousness, he argues, consists in explaining the many functions of the brain: how do we recognize a face, a word, or a landscape? How do we extract information form the senses and use it to guide our behavior? How do we generate sentences to describe what we feel?

    “Although all these questions are associated with consciousness,” Chalmers argues, “they all concern the objective mechanisms of the cognitive system, and consequently, we have every reason to expect that continued work in cognitive psychology and neuroscience will answer them. By contrast the hard problem is the “question of how physical processes in the brain give rise to subjective experience … the way things feel for the subject. When we see for example, we experience visual sensations, such as that of vivid blue. Or think of the ineffable sound of a distant oboe, the agony of an intense pain, the sparkle of happiness or the meditative quality of a moment lost in thought … It is these phenomena that poses the real mystery of the mind”."

    Stanislas Dehaene's opinion is "that Chalmers swapped the labels: it is the “easy” problem that is hard, while the “hard” problem just seems hard because it engages ill-defined intuitions. Once our intuition is educated by cognitive neuroscience and computer simulations, Chalmers’ “hard problem” will evaporate".

    Personally, I agree with Stanislas Dehaene's opinion.

    Jonathan Edwards · University College London

    I share Arnold's quizzicalness on Darius Malys. I was not very impressed that he has his feet on the ground. Maybe the empirical observation we should expect is that good sausage goes very well with good beer - especially if you have had a few good beers beforehand.

    I cannot dismiss someone who puts Leibniz in his title but note that Russell said of Leibniz “In this passage the unduly practical nature of Leibniz’s interest in philosophy very plainly appears”. The unduly turned out to be a joke at Russell's own expense but the practicality was well said. I prefer to stick to the realities of squidgy grey matter than draw seven circles in an imaginary nowhere.

    The joy of science is positing something iconoclastic and fanciful and then showing that it is actually the way things work. When one starts out I think one tends to assume that Nature is too subtle ever to provide you with the evidence that you hit on the right idea so one keeps dreams and lab work separate. But Nature is actually more generous I think. She may let you see you have the right answer if you have. So dreams are important but only if you seriously want to test them out. Like Mr Turing.

  • Abdolmajid Ghasemian added an answer in Fusarium:
    Is it possible for Pseudomonas aeruginosa to cause clinical effect through crop consumption?

    I want to investigate the effect of Pseudomonas aeruginosa on Fusarium wilt of tomato. Pseudomonas aeruginosa, being a clinical organism, is it possible that it cause an infection on the consumer of such produce( tomato fruit)? 

    Abdolmajid Ghasemian · Tarbiat Modares University

    You should use the strains that have the least virulence factors (exo-toxins) ec. standard strain, and also if the individuals to be tested are immunocompromised you should not test on them. Because P. aeruginosa is an opportunistic bacterium.  

  • Elena Yu. Filinova added an answer in Nucleotides:
    How can I search a nucleotide database for a given conserved domain?

    In a genome database (nucleotide sequence) located in my computer, I would like to identify a given conserved domain, e.g., a given PSSM or a given Pfam.

    For this purpose, I looked at PSI-BLAST and DELTA-BLAST, but they are protein-protein search tools, while I need searching a nucleotide database. Similarly, http://pfam.xfam.org/ allows searching protein-protein.

    Is there any tool suitable for me to be used locally on my computer?

    Elena Yu. Filinova · Advanced Biomedical Research Laboratory, RF; Vidipharm Gmbh, Austria

    Dear Giovanni,

    Programmes for making-using your own databases ususally paid ones. Our genetists use several for alignments, VectorNTI and Clustal are simple ones. PEAKS is both for large protein and nucleotide self-selected databases.

  • Is Loretnz symmetry conserved for all velocity ranges?

    I want to know whether Lorentz symmetry is conserved for all the velocity ranges or not?

    Is the Lorentz invariance completely related to Lorentz symmetry; i.e. if Lorentz symmetry conserved then Lorentz invariance is also conserved or there are certain conditions where the Lorentz invariance conserved while Lorentz symmetry is not? what are they if there are such conditions.

    Johan Frans Prins · Sage Wise 66 (Pty) Ltd

    Dear Daniele,

    In theory you are correct. In practice the time is late.

    I can assure you that it is not I who started with insults. The strength of ideas are not important in the "post-modern" era. Physics has been hi-jacked by an insane minority who wants to believe that physics MUST be based on the absurd.

    QM must be weird, simultaneously must be weird, or as Bohr has stated: "reality is based on things that are not real!". Only a demented person can formulate such bullshit, and the time has come to call it exactly what it is: i.e. bullshit! The only way you can fight them is to be insulting since they deserve it.

    Best wishes,


  • Vijayakumar Karuppasamy added an answer in Moths:
    Can any one differentiate the greater wax moth (Galleria mellonella) and lesser wax moth (Achroia grisella)?

    In South India, we saw this greater wax moth (Galleria mellonella) frequently.

    We are not able to control this. The newly divided colonies are easily attacked by this wax moth.

    Vijayakumar Karuppasamy · Kongunadu Arts and Science College

    Dear Dr. Michael Kurz

    I found the  Galleria mellonella during November to Febrauary.

    I taken this photo on 13.11. 2013.

  • Dominik Bork added an answer in ESL:
    Is this a case study - only analyse students' work and conduct interview?

    Research objectives:

    1) ESL argumentative essay: rhetorical and linguistic structure.

    2) ESL writing strategies in producing the essay. 

  • What is your opinion on using the prick test in patients with nasal poliposis to demonstrate allergic rhinitis?

    Please explain your opinion and experience on this subject.

    Hazem Y. Abdelwahed · King Saud University

    Dear Mohamed El-Begermy, would you mention from where we i can download your mete-analysis article?