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

  • Ariadne Tsambani added an answer in Nanocrystals:
    Who can write exactly how Nb and Cu affects the process of nanocrystallization?

    I would like an accurate description and learn something. I know the rule their use.

    Ariadne Tsambani

    Good Evening. Please find attach the link

    .Regards Ariadne Tsambali

  • Mehmet Bostanciklioğlu asked a question in Transgenics:
    Alzheimer animal model?


    We are looking for reliable animal models of Alzheimer Disease. You recommend us what type of model except from transgenic?

    Thank you in advance.

  • Han Ping Fung added an answer in Theory of Planned Behavior:
    Can the external variables in theory of planned behaviour be extended to include other variables?

    I am trying to understand the adoption of certain tool using behaviour models. when using theory of planned behaviour can the " background /external variables"  be extended to include for example the context or specification of that tool?

    Han Ping Fung

    Can the external variables in theory of planned behaviour be extended to include other variables?

    I think they can but ensure you have done your literature review that there was relevant logic / precedent / theory / framework that support your insertion of other variables into your TPB research model.

    I'd done that for other theories like TAM & UTAUT - if you want can refer to the following RG links:





    • Source
      [Show abstract] [Hide abstract]
      ABSTRACT: As IT outsourcing services are crossing path with cloud computing services in the new dawn of cloud computing era, there is a lacking of research and framework to explain how IT outsourcing service provider will intend to adopt cloud computing based on some competitive analyses of its business environments. This research developed a conceptual framework to measure such intention underpinned on both Porter Five Forces (Porter, 1980) and revised Technology Acceptance Model (Venkatesh & Davis 1996). This paper is only the first phase of this research. Literature review is conducted, research problem is identified, research objective and questions are provided. Conceptual framework, hypotheses as well as the research methodology are also explained in this paper. Lastly, contribution, limitation and conclusion are also included.
      Full-text · Article · Oct 2013 · Internet Technologies and Applications Research

    + 3 more attachments

  • Arun Chattopadhyay added an answer in Surfactants:
    What are the mechanisms of degradation of surfactants that can occur at high temperature?

    I have question about surfactant degradation at high temperature if someone can help me.
    What are the mechanisms of degradation of surfactants that can occur at high temperature?
    If you have articles, books, readings and references to advise me? Thank you.
    Nanofluids prepared by dispersion of nanoparticle in basefluid (water, oil , …) cannot be stable if the temperature increases and surfactants degrade,
    have you an idea about the possible working temperature in the case of SDBS such as a surfactant for water and alumina ? and in the case of oleic acid as a surfactant for oil and Cu nanoparticles ?
    Thank you

    Arun Chattopadhyay

    What is the temperature you are refering to? Oxidation, oxydative degeneration, molecular transformation, disociation, association etc. etc. a variety of phenomena can cause a surfactant to fail or degrade.  

  • Joseph L Alvarez added an answer in Polymers:
    Which surface is affected by gamma radiation?

    In gamma irradiation of polymer experiment, which surface is more influenced, the entry or the exit surface and why?

    and when the film thickness is in micro range, is that make difference? or is there a difference between the entry and exit for small thickness samples? 

    what about gamma attenuation in polymers is it effective to use polymers as a shielding material since it is rich of hydrogen.

    please give some details in your answer??

    Joseph L Alvarez

    What are you reporting that requires units? If you are reporting the gamma beam energy it is kerma, free-in-air. The unit is Gy. If you are reporting the dose to the polymer it is energy deposited and the unit is Gy.  To report dose to the polymer you will have to calculate the energy deposited using assumptions on the kerma distribution in the polymer or you will need a method to measure it. Sv is inappropriate as it is a unit of risk. 

    Ion fluence assumes you have a measurement or estimate. The unit should be that used to measure or estimate. The unit cm-2 seems appropriate.

  • Ariadne Tsambani added an answer in FFT:
    How can I Demodulate phase from grating frequency in "moving grating Kare method fringe analysis"?

    In kare method you need an additional digital grating to move on your morie pattern  4 times in spatial method fringe analysis. Now my question is when my phase is modulated with grating pattern what is it mean? Is there any way to remove it from your phase?

    our final equation of calculating phase "phi(x)=atan(( FI4-FI2) / (FI3-FI1) );" where FI is inverse Fourier transform of fft of four image

    Best Regards

    + 1 more attachment

    Ariadne Tsambani

    Good Evening. Please find attach the link

    .Regards Ariadne Tsambali

  • Micaias Rodrigues added an answer in Education:
    Definition of productivity in education sector?

    Do you have an idea about the definitin of productivity in education sector?

    What is the difference betweeen efficiency and productivity in education?

    Thank you 

    Micaias Rodrigues

    Sourour, I inserted three links, two classical and a recent paper. I wish help you. Good work.




  • François K. Mulenga added an answer in Grinding:
    How to design an experiment to investigate the wear rate of grinding media with increasing fineness of grind during wet milling of a mineral ore?

    Metallurgy related ,comminution , wet milling

    François K. Mulenga

    Hi Ashley

    There is a paper by D.D. Howat and L.A. Vermeulen that deals with your specific query. The full reference is as follows: D.D. Howat, L.A. Vermeulen, 1988. Fineness of grind and the consumption and wear rates of metallic grinding media. Powder Technology, vol. 55, no. 4, pp. 231 - 240. DOI:10.1016/0032-5910(88)80033-0

    It is unfortunate that I am still struggling to find it on my hard drive. But if you have access to it, please download it. It is spot on as far as your question is concerned.

    You could also download the following PhD thesis with the link provided in brackets (https://open.uct.ac.za/bitstream/handle/11427/9657/thesis_ebe_1993_powell_ms.pdf?sequence=1). It is readily available and has elements of answers to your question.


  • Shoba Balaguru added an answer in Environmental Engineering:
    What do you mean by environmental engineering?

    Environmental engineering is a new title named for Sanitary engineering as one branch of civil engineering, Environmental engineering is a relatively young branch of the engineering profession but is projected to be among the fastest growing. It has developed in response to the serious problems of environmental contamination caused by the activities and waste products of our modern society. The U.S. Department of Labor, Bureau of Labor Statistics projects that jobs for environmental engineers will grow by 25% from 2006 to 2016. Pollution has many sources and is found in the land, air, and water around the globe. Environmental engineers usually
    specialize in dealing with certain types of pollution or a particular resource: Water, sewage, water treatments  water  desalinization, so how can we react  with environmental engineering to developed society? 

    Shoba Balaguru
    • Environmental engineering is the branch of civil  engineering. Using the Engineering principles to protect the people from the adverse environmental  effects such as air pollution, water pollution,  soil pollution etc., as well as improving the quality of our environment.
  • Frederico Mestre added an answer in ArcMap:
    What software or program can be good to perform Species Distribution Modelling ?

    Hi everyone.

    I would like to know about the spatial analysis program(for Species Distribution Modelling).

    I tried using the MaxEnt and ArcGIS(ArcMap 10.1). MaxEnt is pretty useful. while using this program or software, I have question. I wonder if the new spatial analysis program Like MaxEnt.

    If you know new(in my case... haha) program, please recommend!!!!!

    ps1. i'm not good at R. if possible, please Recommend except for R package.

    Thank!! You have to be happy.

    Frederico Mestre


    I've used mostly R packages, which is the best option (with packages such as ENiRG, biomod2, sdm and dismo). ENiRG has a user interface that makes it easier to use.

    Outside of R I've tried these:

    Biomapper: http://www2.unil.ch/biomapper/

    ModEco: http://gis.ucmerced.edu/ModEco/

    SAM: http://www.ecoevol.ufg.br/sam/

    Open Modeller: http://openmodeller.sourceforge.net/

    But I still think that using R is the better option, since you have a lot more control over your models and you can combine resources from several packages.



  • Mustafa Fayez added an answer in Raspberry Pi:
    How can I begin learning and coding for Raspberry Pi 2?

    Any tips and video tutorials from our experts will be greatly appreciated. Thanks.

    Mustafa Fayez

    Hello Sneha, 

    You can find the library/driver for your TFT screen here:


    and here is the tutorial:


    Best wishes.

  • Syed A Ali added an answer in Exosomes:
    Do you use RNase treatment prior to RNA isolation from exosomes?

    I would like to know if you are using RNase to digest RNA outside EVs? If yes, how do you stop RNase before exosomes lysis to protect RNA inside?

    Syed A Ali

    In our hands 5 min treatment worked. We used RNAse from Thermo Fisher. Flash freezing is necessary to inhibit RNAse activity. We add Trizol to frozen sample and continue with RNA extraction. I have not used kits so can't say much about them. However, most kits do use strong chaotropic agents to denature enzymes in the first step so I guess it should work.

  • Maximilian Holland added an answer in Indigenous People:
    What are the effects of colonialism, capitalism on indigenous people?


    People relations 


    Please give ideas and post journal articles

    Maximilian Holland

    Depending what you have in mind by the term "people relations" - you may find my recent book on kinship (Social Bonding and Nurture Kinship) useful to this part of your question, especially my chapters 8 and 9, and the references therein. Changing symbolic, economic/ecological and political factors (from colonialism or otherwise) can all exert profound changes on all scales of social relations. I give some illustrative examples in chapter 9.

  • Janine Hofmann added an answer in Primer:
    How is primer annealing and optimal concentration influenced by 5' dangling ends in PCR?

    Dear all,

    Just wondering about the effect of very long 5' dangling ends (>60bp) on PCR in the first few cycles. An obvious thing is that after extending them once, they are effectively not dangling anymore, so a two-step PCR is more effective.

    I wonder whether it would be better to increase annealing time in the first few cycles, so since the dangling end is an impediment they have more time to bind? Or conversely, should annealing time be reduced to 5-10s, so the dangling end has less chance for non-specific binding? Or would a lower (or higher) primer concentration help?



    Janine Hofmann

    Hello Ruben, because I was working with challenging GC-rich streptomycetes I used touchdown PCR (the primer had a 12bp long 5` dangling end). It´s related to the explanation Divya gave. In the first part of the PCR I start annealing at something like 2-3°C above the calculated annealing temperature to get more specific products and decreasing the temperature every cycle by 0.5°C for 10-13 cycles (worked well in my case). In the second phase you benefit from the presence of the specific products. Here you just run some additional PCR cycles with a decreased temperature (in my case 5-7°C less than the initial annealing temperature). Maybe that´s an option to try.

    Best, Janine

  • Alejandro Martin added an answer in Gel Electrophoresis:
    After running SDS, why do we put our gel in solution of acetic acid and methanol?

    I was reading SDS PAGE and methodology it was mentioned, I searched it online but i couldn't find the answer.

    Alejandro Martin

    I don't know your specific application, but probably for fixing the gel, i.e. preventing the diffusion of protein bands and the subsequent lost in resolution, sensitivity, etc.

    What else do you do after HAc/MetOH?

  • Dileep Md added an answer in IT Systems:
    What is the purpose of reducing the PAPR in the OFDM systems.?

    PAPR - peak to average power ratio

    OFDM - orthogonal frequency division multiplexing.

    Dileep Md

    THANK YOU SO MUCH , Vincent . 

  • Joseph Kinyanjui added an answer in Textiles:
    Can anyone send me latest statistics on global Textile market and exports?

    Latest statistics available on global Textile market and exports of its different segments

    Joseph Kinyanjui

    Also look in the UN COMTRADE DATABASE ( link provided)

  • Mary Durfee added an answer in Security Policy:
    Can we refer to the High Representative of the Union for foreign affairs and security policy as institutional innovations for the EU construction?

    What are the differences between the High Representative of the Union for foreign affairs and security policy and the former would-be minister of foreign affaires of the EU as envisaged by the Constitutional Treaty? Thank you

    Mary Durfee

    This is she.  EEAS was also created in the general sense from TEU, with more detail in the TFEU.  Changed reporting in the EU as a VP.  Seems to be an increasingly strong role, though EEAS (which reports to the HC/VP still struggles.  HC/VP used to have offices with the EEAS, but Juncker moved the office (and the person) to Berlaymont. If you need citations....

  • Ariadne Tsambani added an answer in Zirconium:
    Why in solute theory m and K are assumed to be constant?

    According to solute theory, to calculate GRF, there are two assumptions:

    1- m is constant

    2- K is constant

    The literature says that for Aluminum base alloying systems m for titanum is 30 and for zirconium is 4.5. 

    first of all: m= 30 is valid for the amounts of Ti less than 0.15 wt. %. after that the slope changes dramatically and this constant slope is not valid.

    But for Zirconium. please take a look to the attachment. How can i calculate the slope? which slope is considered for Zr (m=4.5). 

    Therefore, I have an important problem with this theory, It is valid until the slope is constant or doesn't change too much. but for Zr and Ti the slope change dramatically after 0.11 and 0.15 wt. % respectively. So, how could this theory be valid here? In other words, what is the verified range for these elements?

    Ariadne Tsambani

    Good Evening. Please find attach the link

    .Regards Ariadne Tsambali

  • Ariadne Tsambani added an answer in Mechanical Engineering:
    What is the physical significance of lode angle which is used in shear modified GTN model ?

    As far i know lode angle which is based on the third invariant of deviatoric stress. 

    Ariadne Tsambani

    Good Evening. Please find attach the link

    .Regards Ariadne Tsambali

  • Ariadne Tsambani added an answer in LS-DYNA:
    What is and how can I use this lS dyna? Can someone suggest its use in FEM for incremental sheet metal forming?


    Where to start?

    need knowlegde of which softwares?

    How to give conclusions?

    Ariadne Tsambani

    Good Evening. Please find attach the link

    .Regards Ariadne Tsambali

  • Mehmet Sinan Iyisoy added an answer in Graphs:
    How to get a graph gathering different variables?

    For example in my case i need to get a relationship between percentage of steel fiber, aspect ratio, wlc and compressive strength .

    Mehmet Sinan Iyisoy

    This is not possible.

  • Vy Nguyen asked a question in 3D Cell Culture:
    How to exchange media in hanging drop technique?

    Hello everyone,

    I am using hanging drop method to make 3D cell culture. But I am struggling with handle the spheres when I exchange the media.

    Please help me if you have any experience with this problem. Thank you so much!!!


  • Mahendra Narain Mishra asked a question in HLA:
    How important are anti HLA DQA1 antibodies in first time and retransplants in the absence of class I sensitization ?

    We have come across some patients of deceased donor list who are being worked up with high level of anti DQA antibodies.  

  • Kulasekaran Ramesh added an answer in Fertilizers:
    Any review article on agronomic efficiency, physiological efficiency, applied inputs' efficiency of various nutrients for crops/cropping systems ?

    fertilizers management is important from viewpoint of sustainable production. Various efficiency indices have been employed in literature and worked out by researchers under different management options.

    agronomic efficiency

    physiological efficiency

    apparent recovery efficiency

    contribution from soil

    all these indices values are dynamic and dependent upon biotic and abiotic stresses.

    Efficiency of micro-nutrient fertilizers is quite low, and we are trying to evolve technique through new products and agronomic management for enhancing the efficiency of these costly fertilizers.

    we are interested to know the range for specific nutrients as far as these indices are concerned? 

    Kulasekaran Ramesh

    May be the range will be very wide since there are several factors involved in these calculations. 

  • Ariadne Tsambani added an answer in Clustering:
    Any advice on clustering distribution obtained by three dimensional atom probe (3DAP) technique?

    As we know, the resolution of 3DAP is anisotropic. The best resolution is reached along the needle axis direction, and could below 0.25 nm. However, the resolution along transverse direction is worse, and may around 1nm. Then, when we apply radial distribution function to analyze the atomic pairing relationship in 3DAP data, the result with 1nm is not reliable and may be wrong. I think this conclusion is true and what do you think. Is there any other reliable method to find the nano-sized cluster in a system. Thanks.

    Ariadne Tsambani

    Good Evening. Please find attach the link

    .Regards Ariadne Tsambali

  • Aykut Saglam added an answer in Plant Biotechnology:
    I m looking fr a proline deficient maize mutant. can anyone help me?

    proline deficient maize seeds are necessary for our study. I have got some from maize mutant database however the mutants produce more proline than I expect. so I need a mutant having deficiency in prole biosynthesis. I will be appreciated If anyone can help me to find?

    Aykut Saglam

    thanks for your answer. I have asked for some seeds however sending seeds from china to other countries is not allowed. I will keep searching

  • Faizal Vohra added an answer in Pharmacy:
    Why pharmacy profession are not well recognized/not developed in developing countries till 21 century?

    Why pharmacy profession are not well recognized/not developed in developing countries till 21 century?   

    Faizal Vohra

    in case of india there is dpharm,bpharm,pharm d,mpharm so what is the use of all this even a 2 year diploma guy will get a licence for pharmacist and those who study 6 yrs pharm d they get after 6 years. untill this diploma and bpharm courses are not shut down there will not be any value of pharmacist and we require a single degree for pharmacist and it is the pharmacist that makes a drug and informs a doctor about for what it is used after doing research and doctor gives that information to patients hence pharmacist should have that value but unfortunately pharma companies have lower the value of pharmacist by making them MR which keeps waiting for doctor as a result doctor dont gave them that much value 

  • Lutz von Wangenheim added an answer in Circuits:
    Who knows the properties and the working principle of this circuit?

    Recently I came across with the shown circuit.

    It has some interesting properties. Is there anybody who has used such a circuit already? Both opamps are assumed to be ideal.

    Lutz von Wangenheim

    Ey Cyril - interesting paper. Thank you so  much!.

    In principle, I agree with you. Yes - it is somewhat "odd" to say that V1 would be the input to the 2nd opamp - because the whole block (including R1, R2) is no linear amplifier at all. On the other hand, the opamp alone works in its linear range because of the dominating negative feedback.

    Therefore, my description of the whole arrangement is as follows:

    * We have an opamp (opamp 2) with positive resistive feedback kp=R1/(R1+R2) and an active (opamp 1) negative feedback factor kn which dominates as long as kn>kp.  Therefore, opamp 2 works in linear mode.

    * Anywhere within this active negative feedback path (opamp 1) is a signal source Vindiff , which is responsible for the two opamp output voltages V1 and V2.

    * This case can be treated as  a "disturbance transfer effect" known from the general control theory.  This is because such "disturbances" may be effective anywhere within the loop. Hence, we can define two "disturbance" transfer functions T1=V1/Vindiff and T2=V2/Vindiff. And the results are:

    T1= (- R1/R2) and T2= -(1+R1/R2)

    What do you think about this view?

  • Mohan Chandra Pradhan added an answer in Final year project:
    How to set the target vector in neural network in MATLAB?

    Hi, I am doing my B.Tech final year project on Abnormal Activity Detection in MATLAB. I'm using Neural Network to train my datasets. I have feature vectors of the frames of the video. I want to know how to set my input vector and target vector for a dataset of videos. Please help!!

    Thank you.

    Mohan Chandra Pradhan

    Dear Researcher

    please refer to the links if it is helpfiul to you.


    + 1 more attachment