Q&A

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

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  • Arno Gorgels added an answer in Photons:
    Do you think that a two-laser-beams-in-vacuum collision will produce a positron/electron pair?

    Considerations of a numerical vacuum-structure suggest that electron/positron pairs can be produced by colliding photons under defined theoretical circumstances. The event is supposed to occur spontaneously in nature too, but only effectively in vacuum. This sequence would be the opposite from the often measured positron-electron annihilation. The result of the experiment could assist to understand the location of antimatter (of this sort) in the universe and the role of the structure of the vacuum. The problems of constructing the proper vacuum chamber as well as the difficulty of the measuring devices and their noise level thematic are supposed to be understood and controllable. What is your opinion? Is it an experiment worthwhile to be conducted? 

    Arno Gorgels · Principia Naturae

    What is selection?

  • Shelina Walli added an answer in Teacher Education:
    I'm trying to get the following publication but in vain

    Hogg, L. (2011). Funds of knowledge: An investigation of coherence within the literature. Teaching and Teacher Education, 27, 666–677. Irzik, G. (2001).

    Shelina Walli · The University of Arizona

    Thank you Ana.

  • How can I decide which parameters to use to test success in a wireless networking project?

    The project is a gate way "one wireless network protocol connects devices work using another protocol". 

    What software and hardware tools that can I use to measure data flow?

    Chandramathi Soundararajan · Sri Krishna College of Technology

    As Mr. Walker has pointed out you can use network simulator NS-2 or NS-3. Since you are using at the gate level, it is important to measure the delay, throughput, latency and the effect of noise on the signal. 

  • Markku I Tammi added an answer in T Lymphocytes:
    Is hyaluronan biotin sodium salt (Sigma) soluble in water?
    Has anyone tried to dissolve hyaluronan biotin sodium salt (Sigma) in water?
    Markku I Tammi · University of Eastern Finland

    We have biotinylated hyaluronan in the lab and the product was soluble. Perhaps too high substitutuion level might decrease solubility. We have no experience on Sigma's product.

  • Abdelaziz Meddah added an answer in Sound:
    What kinds of materials provide the highest sound absorption on application of sound insulation?

    I am looking for such kinds of materials that are used as common sound insulation on construction industries.

    Abdelaziz Meddah · Université de M'sila; Université Mohamed El Bachir El Ibrahimi de Bordj Bou Arréridj

    I have no idea exactly on the application of your material. In my opinion the rubberized concretes also have better performance against sound-insulation

  • Jiang Shaohua added an answer in Resins:
    Which would be the natural fiber wind mill blades?

    I am willing to do natural fiber composites of windmill blades with Prosopis juliflora and water Hyacinth fibers with pp or any resin. Any suggestions for the types of resin or polymer used? Types of testing required? Types of manufacturing method?

    Jiang Shaohua · University of Bayreuth

    I have done some work on composites and have several publications. you can find them in the following Research Gate link.

    https://www.researchgate.net/profile/Jiang_Shaohua2

    Here are some suggestions for your questions.

    polymer: PMMA, PLA, TPU, ecoflex, PCL, epoxy, etc

    testing: tensile test, TGA, DSC, FT-IR, SEM, etc

    manufacturing method: extrusion, film casting, layer-by-layer deposition, electrospinning, etc

    I hope these can help you.

  • Martin Schulz added an answer in Inverters:
    Resonant Inverter

    I am building a resonant inverter parallel one to make the load current independent of the load impedance variations. Load power is 100W to 1KW. at a resonant frequency of 10kHz. But there is a variation of load current for varied loads. What could be the reason ?

    Martin Schulz · Infineon Technologies

    Dear Birendra,
    as there are numerous reasons for this behavior, it will be difficult to give a satisfying answer.
    Some major things that might contribute to this effect may be:

    - The current regulation loop's bandwidth,
    - The accuracy of the current measurement,
    - low frequent oscillations in the setup 
    - missing voltage magnitude to drive high currents in high impedances.

    In case of varying output impedances, there is a possibility that the output current changes because the resonant frequency of the design is slightly shifted and a fixed frequency does not respect this, leading to a miss-tuning and thus a voltage sagging may occur leading to a current lower than expected.

  • Cyril Mechkov added an answer in CMOS:
    Can a cmos inverter be used as a current amplifier?

    I saw an article with cmos inverter as amplifier, but it seems to be for voltage. Can a cmos inverter be used as current amplifier?

    Cyril Mechkov · Technical University of Sofia

    Here is an idea of an op-amp current amplifier...

    The ordinary transimpedance amplifier (see the attached picture below) converts the input current into an output voltage. It consists of a resistor R connected between the op-amp output and the inverting input. Connect a voltage divider R1-R2 between the op-amp output and the resistor R: R1 connected to ground and R2 (your load) - to the op-amp output. R1 should have lower resistance than R.

    The op-amp will change its output voltage so that to keep the voltage drop VR1 equal to the voltage drop VR. As a result, the proportion between currents will be IR1/IR = VR/VR1, and the total current flowing thrugh R2 (the load) will be IR2 = 1 + R/R2. The gain of this current amplifier (multiplier) will be 1 + R/R2... Really, the load will be floating but...

    (Maybe, I might do it faster if I had drawn it:)

  • Marcelino T Suzuki added an answer in Gene:
    Please can anyone help me to use the STADEN software?

    Please anyone help me to use the STADEN software. It is essential for my work. Is there some other softwares which can be used for the alignment of gene sequences? to find out the variation other than BLAST ?

    Marcelino T Suzuki · Pierre and Marie Curie University - Paris 6

    are you using Sanger sequences?

  • What are your views, perceptions about magic?

    magic is used to describe an influence, effects, to express our feelings towards beautiful things such as music, literature.,,,etc.

    what is the realty of magic? is it a concept of our brains? can be learnt? is it a science? or a myth?

    please share your valued opinions 

    Ahed Jumah Alkhatib · Jordan University of Science and Technology

    Dear Gerald Vineyard,

    thanks for initiating this thread. Actually, i agree with your answer. actually, I would like to have a depth discussion in this topic and to explore the effect of magic in researchers. some times, we describe good work as magic, or certain speech of a leader as magic. is it that good to describe things as magical? 

  • Eman Moustafa asked a question in EstimateS Software:
    Difference in Differences dofile - STATA

    Dear Colleagues

    I am trying to estimate Difference in Differences Treatment Effects model on stata but I don't have the dofile. Any help?

    Thank you in advance.

    Eman

  • Costas Drossos added an answer in Wellness:
    What is the best form of answers in RG?

    I have seen answers very long, so that no body wants to read them completely. On the other hand the questions remains. I believe that the answers should be “epigraphic” summarising in few words the substance of the answer. Furthermore such answers should be accompanied with references to enhance knowledge as well as lengthier development that can be attached.
    A long answer, should be so well written, that you do not want to leave it before you finish. If you are a very good writer, try long answers! If you know your subject you could express it with a minimun words.

    Costas Drossos · University of Patras

    Dear Louis,

    Although I enjoyed your posts, they are very long!  

  • Costas Drossos added an answer in Diving:
    How far is a virtual technologies usage affecting our healthy and socially life style?

    Virtual technologies are technologies which serve for the representation of elements and events of the real, invented and abstract human worlds in the form of dynamic images. These worlds or their parts are visually perceived and interpreted by humans like as really existing physical objects. Therefore, virtual images are used for the optical observation of different simulated behaviors which either are not observable by human eyes or do not exist physically.

    The virtual reality technology (VRT)however, is a multi-disciplinary comprehensive technology, which appears following the computer technology, computer graphics, computer network technology, image processing and pattern recognition, intelligent connection technology, multi-sensor technologies, pronunciation processing and acoustic technology fast developments and so on. In recent years, VRT has been used widely in the field of sport such as diving, gymnastics, trampoline, basketball and skiing, especially at diving and trampoline. The virtual reality technology, virtual reality modeling language theories, especially the application of the virtual reality technology, and the three-dimensional visualization emulation technique in field of sport were discussed in the literatures.

    In the Arab world, technology is imported as fast as it is invented. The use of various types of multiple technologies is spreading widely. Nevertheless, in the field of sports and physical activities the effects were negative in terms of social life style and healthy life style respectively. Instead of developing athletes and taking advantage of such technology, it affects our social, behavioral and health life style to virtual reality as its entity itself. Families are communicating via smart mobiles, iPods, Ipads and other forms of virtual sphere of spatial and temporal ecology more often than commuting to each other physically. The sedentary life styles are prevalence among children, adolescents, and adults for both genders.

    Costas Drossos · University of Patras

    Dear Marcel,

    One can go one step further and say that we live in a kind of "Matrix", where we are bioprograms, and the environment it is a complex bioprogram. 

  • Gareth Lewis added an answer in Methanol:
    Can someone clarify my TLC Results for me?

    Here I show a compound seperated through TLC and got a single spot. My hitch is under longer UV I see a green fluroscent centre and a blue periphery. So does this blue reveal any scattering effect or it is the presence of two compounds that run the same distance. The mobile phase was methanol

    Gareth Lewis · Gareth_PanChem

    Thank you Balaji.

    So, you could possibly have used ethyl acetate (as 100% or in combination with some other non-polar solvent) in the TLC preparation. When I normally think of ‘two phase’ extractions I would think of ethyl acetate mixed with some other organic solvent. However, I’m guessing that you may have used 50% ethyl acetate with 50% water, though I’m not sure. Yes, I realise it’s an unknown compound, but I was wondering whether it was synthesized or extracted from plant material etc. since someone may have performed a similar experiment. For example, if you anticipate that you have extracted an alkaloid, you may then like to consider using alkaloids as standards in TLC (using alkaloid-specific stains?) and HPLC. I wish you good progress with the HPLC and methods development.

  • Rajiv Pandey asked a question in Climate Change:
    Functional formulation of Social Vulnerability and adaptation due to Climate Change

    The three dimension of vulnerability - Exposure, Sensitivity and Adaptive capacity can be measured through indicators. These indicators can be aggregated to define each dimension separately. I wish your  inputs for the following:

    1. The functional form of aggregation of three dimension (such as difference of Adaptive capacity and sensitivity may be divided by Exposure; or any other issues) and reason thereon

    2. How functionally social vulnerability is linked with adaptation (functional formulation) with appropriate functional form 

  • Golam Hafiz added an answer in Coagulants:
    Why is bone marrow so hard to aspirate after hematopoietic stem cell transplant?

    No matter how fast we aspirate, it coagulates immediately.

    Golam Hafiz · Bangabandhu Sheikh Mujib Medical University

    Before procedure heparin should be added to syringe. It can be done in all hematological malignancies, as soon as early as possible following aspiration.

  • How can I build an installer that would allow me to install and execute my code on other PCs?
    I have written a set of codes in Perl for feature extraction from a dataset. I have developed a GUI in C# and linked my codes at the backend. I would like to build an installer using my code, that would allow me to install my code on other PCs and execute it. Can someone give me tips on how to go about it or point me to some references?
    Peter T Breuer · Birmingham City University

    This is a question of the target o/s (windows, bsd, linux, etc). You need to follow their standard.

  • Costas Drossos added an answer in NATO:
    A referendum on full Scotland's independence is in progress. How will the results of this referendum affect the European Union, NATO ...?

    Scotland's independence could bring some reflections to some European regions such as Catalonia, South Tyrol, Flanders, the Basque Country. Even some ideas of ​​new state of Kurdistan can be dangerous, especially for Turkey who would like to become a member of the European Union. What are your concerns about, if any?

    Costas Drossos · University of Patras

    Dear Louis,

    Nations identities are essentially imposed, usually when there is an enemy threatening the whole nation. Without enemies the identities hardly exist. On the other hand, in a decentralised multicultural society, I do not see, how to loose an "identity". So before we talk about "identity" it is good to look at:

    • ERIC HOBSBAWM and TERENCE RANGER (Eds) The Invention of Tradition
    • B E N E D I C T A N D E R S O N Imagined Communities: Reflections on the Origin and Spread of Nationalism
  • pu bo asked a question in Urbanization:
    How do the urbanization quality evaluation

    what are the  indexes on  urbanization quality?Such as population,industry and environment and so on.

  • Annamalai Nathan added an answer in Sap Flow:
    Can anyone tell me how we measure the water mining rate of tree crop ? will xylem sap flow system alone do?

    I would like to know whether just a simple and single measurement system like sap flow meter with TDP or  other probes is  enough for monitoring the water consumption rate of tree crops like apple, rubber, mango etc.

    Annamalai Nathan · Rubber Research Institute of India

    Thank you very much Dr. Georgianne Moore

  • Christopher James Davia added an answer in Clouds:
    Can atmospheric bacteria and clouds be used to tackle the growing CO2 problem?

    Recent studies have revealed an intimate relationship between micro-organisms and cloud formation. It seems that an important 'catalyzing' agent for water droplet formation are tiny bacteria. Research has revealed that the atmosphere is host to an enormous biomass: - bacteria may spend their entire metabolic lives suspended in the air and never 'know' the earth!

    Might it be possible to utilize these organisms as a carbon sink?

    Presumably, atmospheric CO2 is already involved in the metabolism of these organisms. However, it may be possible to modify strains of bacteria to make them more efficient at removing CO2 from the atmosphere - perhaps by increasing their growth rate. This strategy could be used in conjunction with a program of atmospheric seeding to promote cloud formation.

    Harry,

    I have no references (Richard has one, I think) - I watched a documentary recently

    Bacteria act as nucleating agents that allow water droplet formation at a much higher temperature than would otherwise be the case.

  • Rajiv Pandey added an answer in Research Design:
    How can we use experimental research design in social science?

    Actually, experimental research design use in science, but here I learn how can we use this design in social Science?

    Rajiv Pandey · Hemwati Nandan Bahuguna Garhwal University

    One has to really look for the objective and the principals of design - Randomisation, Replication and Local Control. The selection of subject will be most important consideration to use DOE. I think this can be applied. Various design such as CRD, RBD, LSD with factorial experiments has potential for the same.

  • Golam Hafiz added an answer in H&E:
    How do I interpret a lymph node with effaced architecture that stains positive for both CD20 and CD3 on the same section on IHC?

    I am using the above antibodies together with LCA to confirm retrospectively cases previously diagnosed as lymphoma on H&E in my local set up. I discovered that many of the cases even though they appeared to have effaced architecture(i.e. absences of follicle and sinuses) stained positively with almost the same proportion for both CD20 and CD3 on IHC. Could these be regarded reactive cases?

    Golam Hafiz · Bangabandhu Sheikh Mujib Medical University

    Cytogenetics study should be done

  • Dipendra Gautam asked a question in Environmentalism:
    What do you think about environmental pricing for industries?

    As people are stricken by the severe impacts of industry, can we enforce environmental pricing?

  • What features or functions in a PLM (product life-cycle management) tool, you consider most important for productivity gains in product develoment?

    There are many PLM tools available for engineers to aid in the product design and development process. Some features let you capture geometry (points, lines, arcs or surfaces). Some let you capture knowledge or rules. Some help make the tools easy to model and use. Some functions/features provide better gains in productivity than others.

    Brian Prasad · California Institute of Technology

    A users'  Interest Group in Knowledge-based Development (KBD), you can subscribe to:

  • Dipendra Gautam asked a question in Mining:
    What are the effects of mining Stone, Gravel, and Sand (SG&S)?

    Beyond environmental, hydro-geological, and social problems, what could be other effects of excessive mining SG&S?