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

  • Abhishek Vaish added an answer in Humerus:
    In a midshaft humerus fracture with neuropraxia is closed nailing better or plating?

    35 Gentleman,H/o acute trauma with wrist drop

    Abhishek Vaish · Sancheti Group

    If operative option is taken then USG should be done along the arm to look for radial nerve entrapment.

    Early exploration and repair of severed nerve have not been proved to produce any better results than repair at a later date (Campbell 12th ed)

     Review article by Shao et al gives an algorithm for the same.

    so nailing is also a good option with its own advantages.

  • Hanno Krieger added an answer in Information Technology:
    Without the use of modern information technologies to conduct research work possible?

    Dear collegues,thank you very much in advance.

    Hanno Krieger · retired from Justus-Liebig-Universität Gießen

    Dear Anup,

    wonderful essay which reflects my own experiences. Stepwise working, correcting, scrapping and changing.

  • Milad Gholaminia added an answer in Geotechnical Engineering:
    Is there any criteria for controlling soil nailing wall deflection?

    I am analysing some soil nailing slope for my thesis. Is there any criteria or limits for wall deflection. There is some criteria for allowable FS. for example 1.5 in FHWA. Whats the allowable deflection of soil nailed wall?

    Milad Gholaminia · Iran University of Science and Technology

    Dear Dr Fathalla M. El-Nahhas

    Thanks alot!!! it really helped.
    I can not open the file that you have uploaded here. could you please send it to "mgholaminia@civileng.iust.ac.ir"

  • Peter André Busch asked a question in Dictionary:
    What is the difference between 'term', 'notion', and 'concept'?

    Seems like 'term', 'notion', and 'concept' are used differently in different papers. Are there any distinct guidelines on how to use these? I have consulted the dictionary but some thoughts from others would be nice :)

  • Ata Joodavi asked a question in Groundwater Quality:
    Looking for information on relationship between deterioration of groundwater quality and groundwater depletin. Could anybody help?

    I am looking for research about the mechanism of water quality deterioration in over-exploited aquifers WITHOUT sea water intrusion.

  • Basant Kumar asked a question in Abaqus:
    Life estimation of Rubber components using computational models available in ANSYS or ABAQUS. Can anyone suggest literature on this aspect ??

    Rubber seals , Rubber Liners especially

  • Alicia Valero added an answer in Electrics:
    Research papers and reports on the composition of EEE?

    Does anyone know about any comprehensive research studies on the composition of different Electric and Electronic Equipment such as mobile phones, computers, monitors, domestic appliances, etc?


    Alicia Valero

    Alicia Valero · Centre of Research for Energy Resources and Consumption

    Thanks for your helpful advice!


  • Shaista Aamir Ali added an answer in ANFIS:
    What is the difference between hybrid and backpropagation learning in ANFIS?

    What is the difference between hybrid and backpropagation learning in ANFIS? Also what is the mathematical equation for both

    Shaista Aamir Ali · Punjab University College of Information Technology

    In Matlab ANFIS uses hybrid method for optimizing ANFIS structure than this hybrid method is combination of which methods?

  • Shalini Gupta added an answer in Separation Techniques:
    Why is the production water slightly black in colour and I get and black deposit on inside injection wells?

    I work in oil industry as Field Engineer. Recently I was in the field (a gathering park) to collect a production water sample to conduct a residual oil determination because the water that is separated in the oil-water separation process is the re-injected into injection wells. When collecting the sample from the outlet line of the injection pumps (used to pump the water to the injection wells) I have noticed that the water sample was slightly black in color and after hours changed the color to yellowish / turbid water.

    Also they had a workover intervention to one injection well (into which is pumped the separated production water) and I observed on the inside of the tubing a deposition layer black in color. This deposit is not so hard (like scale), but is a mixture of soft –slimy material and parts which were slightly more harden. After I kept this deposit sample inside of a container (glass and with a lid) I have observed that it started to change color into rust iron color.  

    Could anyone advise what is happening? Could this black color of water indicate the SRB bacteria contamination? The black deposit from the inside tubing of production well could be iron sulfide, biomass? Could anyone suggest some field test to conduct on the deposit sample to identify what is the nature of it?

  • Ali Amanati added an answer in Mycobacteria:
    Which drugs is Mycobacterium fortuitum naturally resistant to?

    I want to know what are the drugs that has no effect over M. fortuitum. 

    Ali Amanati · Shiraz University of Medical Sciences

    Hi Dear

    Nontuberculous mycobacteria (NTM) including M. fortuitum are naturally 

    resistance to antituberculosis drugs such as isoniazid, ethambutol and rifamycins.

    M. fortuitum also produce beta-lactamase which less susceptible to clavulanic acid.

    Mycobacterium fortuitum isolates are usually sensitive to clarithromycin but may

    contain macrolide resistance gene.

  • Pankaj Kumar Gupta added an answer in CO2 Sequestration:
    Is there any lab experiment on migration of CO2 supercritical phase in subsurface?

    I wish to conduct a lab experiment on Migration of CO2 supercritical phase in subsurface, please suggest any previous laboratory work regarding same.

    Pankaj Kumar Gupta · Indian Institute of Technology Roorkee

    Thanks you all, please send if any link to my mail ID: pankajkumarpsc@gmail.com

  • Colin James III added an answer in Trading:
    Can I include both return volatility and trading volume in a mean equation?

    My research is on the relationship between stock return volatility and trading volume. so i included both trading volume and forecasted volatility in a mean equation of GACH (1,1), however my model keeps failing. how do i solve this problem??

    Colin James III · Ersatz Systems Machine Cognition, LLC

    It is possible that return volatility and volume are not related.  It is also possible that the equation is defective.  42-iterations suggests to me that the algorithm is dependent on an undecidable vector space, that is, probabilistic.  Can you streamline your formula into a linear equation?

  • Gheorghe Zaharia added an answer in Massive MIMO:
    What is the channel in Massive MIMO?

    Is it only Ray Leigh fading channel or others?

    What kind of channel model can be used? In massive MIMO, what are the additional properties of channel to consider? And why?

    Gheorghe Zaharia · Institut National des Sciences Appliquées de Rennes

    The MIMO channel does not depend on the routing of data and there is no obligation to use clusters of antennas. This channel depends on the system fraquency bandwidth, the type of antennas, their number and location and their orientation.

    For narrowband MIMO systems, the MIMO channel is characterized by its matrix H of size NxM, where N is the number of transmit antennas and M is the number of receive antennas. This can be the case of MIMO systems using Orthogonal Frequency Division Modulation (OFDM) where each sub-channel can be considered as a SISO (Single Input Single Output) flat channel (frequency not-selective channel). For time-varying MIMO channels, the coefficients of the channel matrix H are random variables, for example Rayleigh variables. When using a base-band representation of MIMO systems, the channel coefficients are complex Gaussian variables with zero mean and equal variance. These coefficients can be independent identical variables but other MIMO channels models can introduce correlations between these variables, as in

    B. Habib, G. Zaharia, H. Farhat, G. El Zein Outdoor-to-Indoor MIMO Hardware Simulator with Channel Sounding at 3.5 GHz, Proc. of VTC-Spring, 2013

    For wideband MIMO systems, each coefficient hmn(t) of the channel matrix H is the impulse response of the SISO multipath propagation channel between the transmit antenna m and the receive antenna n. These coefficients are random functions. They can be consideres independent or dependent, depending on the used MIMO channel.

  • Hari ram Meghwal added an answer in Gromacs:
    Can anyone help with MD simulations using Gromacs?

    During add ions steps using Gromacs

    the overall charge on my protein was calculated qtot -35

    So i have to add positive ions to neutralize the charge on protein.

    then i have added 35 Na ions using command

    but during the energy minimization steps  i got warning for Na ions that

    Warning: atom name 192746 in topol.top and 2HQA_modified_solv_ions.gro does not match (NA - Na)
    Warning: atom name 192747 in topol.top and 2HQA_modified_solv_ions.gro does not match (NA - Na)
    Warning: atom name 192748 in topol.top and 2HQA_modified_solv_ions.gro does not match (NA - Na)
    Warning: atom name 192749 in topol.top and 2HQA_modified_solv_ions.gro does not match (NA - Na)

    WARNING 1 [file topol.top, line 134143]:
    35 non-matching atom names
    atom names from topol.top will be used
    atom names from 2HQA_modified_solv_ions.gro will be ignored

    Fatal error:
    Too many warnings (1), gmx terminated.
    If you are sure all warnings are harmless, use the -maxwarn option.

    What should I do ?

    Hari ram Meghwal · University of Delhi

    Thank you Karunakar Tanneeru sir, i made the changes and got success

  • James Martin McArdle added an answer in Photography:
    Is there a kind of fundamental difference between continuous light source and high speed flash photography?

    We have built a kind of light source that can produce both continuous and pulsed (500 ns) light. When we tested with the continuous mode (dark room and target was a glass of water and dirt) the target was beginning to shine but in pulsed mode the only thing that we could capture was just a thin arc around that glass (the mixture of water and dirt was completely dark and unseen). But why? In my theory there is not any difference between pulsed and continuous light just in making blurred image or sharp image of a moving object!

    James Martin McArdle · Deakin University


    is it likely that there is variation in the effective size and shape of the light source between the two modes? From your description it sounds like either underexposure of the pulsed light, or a difference between point source and broad source light could account for the effect. 

  • Jenny J Gomm added an answer in Cell Culture:
    How to overcome from a fungus contamination in a cell culture?

    If any one is facing fungus contamination or other due to eviormental conditions then what precautions are necessary and how he can prevent contamination?

    Jenny J Gomm · Barts Cancer Institute

    If you are isolating your cells from fresh tissue I would recommend a quick dip (20 seconds) in 70% ethanol before washing 3 times in medium containing pen/strep and 5ug/ml amphoteric in B (Fungizone). It sounds drastic but it really works.

  • B.R. Rajeswara Rao added an answer in Calibration curve:
    How does the calibration program work in Agilent GC-MS?

    The reason that I am asking is that "response" in the calibration generated does not seem to be the area of peak of interest. I see the a huge peak of  IS in the chromatogram and I also see the high number of "correct area"(i.e. 10982323) in percent report. However, when I generated calibration curve using that chromatogram, that response is very small (i.e. 80000) compared to other peaks which seems smaller than IS peak in the chromatogram. Any ideas? 


    B.R. Rajeswara Rao · Central Institute of Medicinal and Aromatic Plants

    Contact Dr. Chandan S. Chanotia, an experienced GC-MS scientist: https://www.researchgate.net/profile/Chandan_Chanotiya2/info

  • T. D. Dongale added an answer in Sensors:
    Why does my chemiresistor IV curve not pass through the origin?

    I'm working with chemiresistors, sourcing V and measuring I. For some of my sensors, I'm getting an IV curve that is linear, but does not pass through the origin. The plot shows a small positive current (+1uA) when V = 0. I know that this result means that my resistor is not ohmic. What else can be inferred from this information? Am I getting slight capacitance?

    T. D. Dongale · Shivaji University, Kolhapur

    Your junction may be wok like a photocell and also check the offset specification of your test equipment.   

  • Christian Wechselberger added an answer in Websites:
    How to identify potential zinc binding motifs of a protein?

    Hi all,

    Do you have any recommendation for a website or software that would help identify zinc binding motifs from sequence of proteins? 

    Thanks so much!!!

    Christian Wechselberger · Greiner Bio-One Diagnostics GmbH

    You could try



    select PROSITE patterns or profiles / Pfam

    Best regards,


  • Durba Biswas added an answer in Agricultural Irrigation:
    Are there any recent papers which uses stated preference methods to analyse surface irrigation water trading among farmers?

    I am looking for studies which have used SP methods to estimate the WTP/WTA values for irrigation water trade.

    Durba Biswas · Ashoka Trust for Research in Ecology and the Environment

    Dear Mohamed El Mehdi Saidi,

    Thank you. the first one looks interesting!



  • Nicholas E Rowe added an answer in Higher Education Research:
    Should we consider giving credit for learning that occurs that is not included in our assessment?

    Students in higher education in many instances work and study and sometimes can apply their learning back on their jobs. However, our course work assignments and assessment may not always capture that application on the job. Should we consider giving credit for learning in a course that is applied in a meaningful way on the job, especially for adult learners  who are motivated to learn when they apply it to their jobs?

    Nicholas E Rowe · University of Lapland

    Mark:  Isn't the idea of outlining specific outcomes to state what a unit /module will achieve?  The assessment then looks at whether this has been done & to what level.  Debra talks about learning that occurs that is not included in our assessment, so trying to integrate things that are not specified is very risky.  If however, we identify elements of learning and implementation that students are likely to encounter, we can reward them by offering credit for achieving a separate (& likely voluntary) unit that will count towards a required credit total. This way, we keep our units specific, yet recognise & reward learning that occurs outside these realms.

    I have seen various examples where the idea of 'freedom' in education & teaching, actually reduces the quality of both areas. Being specific encourages transparency for both teacher & learner, and also emphasises the obligations of both parties. IMO, we need to get creative with the units and options we offer students, but also to retain a high level of quality assurance.

  • Dmitry Guschin added an answer in Silver Nanoparticles:
    I would like to know the exact kinetics of Sol gels/Xerogels?

    From my understanding sol gels are polymer like compounds. After reading several papers I'm failing to understand how one can use the bottom up method to synthesize metal nano particles and then end up with 100 times the amount of metal that was originally put into the solution. Some silver nanoparticle xerogels exhibit 30 grams of silver metal content when originally less than half a gram of silver nitrate was used, doesn't this defy the laws of thermodynamics? Is my mistake the fact that I'm confusing chemistry with nano engineering? 

    Dmitry Guschin · Moscow

    Hello Yusuf, I understand. But even without knowing exact process and time-line, it is a chemical and physical ( not nuclear) process. That extra silver has to come from somewhere. Are you sure that there are no additional silver in solution of silicon? Your initial silver input may serve as initiation of polymerization and this extra silver coming from matter forming colloidal structure. Just a thought. :)

  • Mark Azavedo added an answer in Higher Education Teaching:
    How can the dynamic complexities of the integration of e-learning innovations in higher education teaching practice be demonstrated and explained?

    I am interested in the processes of diffusion and sustainability of innovations and finding the connections between actions that enable and inhibit further adoption beyond the first wave of early adopters of proven elearning innovations in universities?

    Mark Azavedo · Stamford International University

    It's all very interesting. I gave further thought to occasions on which I'd mobilised "academic freedom".In truth, in my mind, these were all concerning administration, rather than academy, though it's difficult to delineate. Certainly, we were talking of nothing high-flown in the realm of ideas (and I certainly wasn't lying in the road to stop a tram, as I once saw a Professor do in Napoli!).

    I saw administrations as holding things back, keeping knowledge in past formats. All fairly accurate in China, often elsewhere in Asia, too.

    However, an interesting thing to think about is that, maybe, those administrations are, in other parts of the world, or in specific Universities, the innovators. Specifically, the people we, sneeringly, dubbed "bean counters" may now be the innovators, driven by the bean count in an ever more commercialised higher education.

    I'm sure that relevant administrations adore, for instance, blended learning and straight online learning, for their cost-effectiveness, and marketing and provision reach.

    Maybe we live in an age of rich irony?

  • Armiya Sultan added an answer in Breast Cancer:
    What is the role of NPAS2 polymorphic forms in breast cancer?

    What is the role of NPAS2 polymorphic forms in breast cancer?

    Do i have some important references from the concerned researchers.

    Armiya Sultan · Pt. Ravishankar Shukla University

    @Ravichandran Panchanathan....thank you

  • Lew Maan Tarng asked a question in Steel:
    Dear members, Does anyone know what is the grade of steel, based on the following elements composition?

    Does anyone know what is the grade of steel, based on the following elements composition?

    Element       Percentage (wt) %

    C                    <0.5

    S                    <0.5

    Si                     3.47

    Mn                  0.75

    Ni                   <0.1

    P                    <0.1

    Cr                    0.89

    Cu                   0.12

    Fe                   90.71

    Mo                 0.2

    B                    0.63

    Al                   0.21

    Ti                   0.21

    V                    <0.1

    W                  <0.1

    Pb                 <0.1

    Nb                <0.1

  • David Harold Chester added an answer in Economic Policy:
    How to reform an economy when corruption becomes the norm of the collective behavior?

    Most of the developing societies, especially after the introduction of Neo-Liberal economic policies termed as economic reforms, have become the havens of economic misappropriation as a norm of collective behavior. The consequences are most severe for both the society and the economy. What are the suggestions you can provide for mitigation of mind boggling corruption in such economies?

    David Harold Chester · private research

    The corruption is in regard to the way that money is being paid out for services rendered. A new system should be emplaced where instead of money, national bonds or shares are paid instead of money. The rights to these shall be confirmed at the bank where they might be cashed only with the personal and independently provided signature of an official in the treasury department. This single person, who has been checked for his status of security, must have his banking services at home and abroad regularly available and should not be permitted to hold unauthorized or new accounts.

  • Edvinas Stankunas added an answer in DAPI:
    Is anyone familiar with tumour spheroids (MCTS) phalloidin staining for confocal imaging?

    When staining both fixed (4.0% PFA in PBS) and permeabilized (1.0% EDTA in PBS) 3D multicellular tumour spheroids (MCTS) with phalloidin for confocal imaging, I get quite unexpected results. Though it may seem that diffusion rate could limit the staining efficiency at the core of the MCTS, but I get reverse results - the core is stained perfectly, but outer rim cells (counterstained with DAPI) seem not to be stained at all (only DAPI appears). Has anyone faced similar problem? Is it probable that PBS washing steps remove phalloidin bound to actin? I would be grateful for any suggestions.

    Edvinas Stankunas · Vilnius University

    Thank you.

  • Mahdi Izadi asked a question in FLUENT:
    Review wall motion. Stationary wall motion relative to adjacent cell zone detected?

    Dear colleagues,

    for simulating a rotating impeller I have used MRF approach,

    Although I have changed all the walls to moving wall relative to adjacent cells with with zero velocity and same direction, fluent error remains,and continuity remains high.

    I think it would be because of a mesh problem?
    Do you have any suggestion?

  • Jayanta Kumar Maji added an answer in Spectroscopy:
    Does anybody know how to compare NIR error and lab analysis error?
    I am using vis-NIR to measure soil samples and calibrate spectral data to predict unknown samples (those of samples have reference value from lab chemical analysis). After I get prediction results from NIR measurement, I want to use prediction error (such as RMSEP or SEP) from NIR to compare error from lab chemical analysis. My question is does it have any principal for this kind of comparison, and how to calculate lab error?
    Jayanta Kumar Maji · Gujarat Ayurved University,Jamnagar

    Statistical design ..Chemometrics may actually sometime reflect good calibration model in Nir spectroscopy. If you compare any standard reference method in context your nir result.Then you can go to F .test for precession of the method. But you can seen model error in context of accuracy,  you may go to cross validation.

  • Binbin Liu added an answer in Railway Engineering:
    Can I use fastsim algorithm to find the forces acting on a number of points from the contact patch (wheel rail contact)?

    can i use fastsim algorithm to find the forces acting on a number of points from the contact patch (wheel rail contact)? also i need help on how to write the matlab programme

    Binbin Liu · Politecnico di Milano

    Actually, you can get the stress of each cell  at the contact patch(as shown in the figure you attached) from FASTSIM, the resultant force can be obtained by integration over the contact patch. It is not difficult to implement the algorithm in matlab, please refer to 'a fast algorithm for the simplified theory of rolling contact' by Kalker. A fortran code was provided as well in the paper.