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  • Anurag Pandey asked a question in Low Power:
    In an open circuit test, current is drawn at low power factor?

    In case of transformer why in open circuit test, current is drawn at low power factor? and in case of short ckt test why current is not drawn at high power factor? Please explain.

  • Rahimi Ali added an answer in Language Testing:
    Do you know any error analysis studies which combine the use of learner corpora with pyscholinguistic research methods, such as think-aloud analysis?

    My initial idea is to conduct error analysis research into "some" and "any" as follows:   1) I  will use learner corpora to determine the errors which learners make with these words at different proficiency levels ;2)  I will design language tests based on these errors; 3) I will either ask learners to think aloud while performing the tests or to provide reasons for their answers straight after the task. ( I am as yet undecided as to whether to use on-going think-aloud protocols or retrospective ones).

    For this reason, I would be particularly interested to know of error analysis studies, in English or any other language, which combine the use of learner corpora with think-aloud protocols. However, I am also interested in studies which combine learner corpora research with any other psycholinguistic research method.

    Rahimi Ali

    hello chris , 

    here are relevant publications :





  • George Stoica added an answer in Capitalism:
    Capitalism vs. Democracy: Are democracies in developed and developing world are able to protect the rights of common citizens against capitalism?

    Mass production of goods (in 15-16th century) divided the society into capitalists and labourers followed by developments of democracies to counter the effects of capitalism.

    What do you think about rights of equality in dimensions of inequality among citizens in different countries and nations?

    George Stoica

    Democracies gives certain right to its citizens - not necessarily against the shortcomings of the capitalism. As Dr. Khan mentioned above, capitalism is first, its citizens come second. Apart from the early years of democracies, it has always been like that. 

  • Fernando Vallejos-Burgos added an answer in Activated Carbon:
    How can I interpret the external surface area of an activated carbon which is greater than the BET surface?

    I prepared a activated carbon with high external surface (2030m2 / g) compared to the BET surface (1230m2 / g)?

    How can I interpret this?
    where: BET surface area = Langmuir surface+ external surface ?

    Fernando Vallejos-Burgos

    Dear Mohamed,

    You can change the dead volumes entered after measuring the isotherm.

    In the same Micromeritics ASAP 2020 equipment, I obtain 48.69 and 16.43 for warm and cold free space respectively. Try plugging those numbers in your sample information, then save and make the report again. Those numbers I obtain using the filler rod, if you are not using, your volumes will be larger.

    You might see something close to the real isotherm after trying that. Then you can measure the free space and the isotherm again. Attached are the relevant pages from the ASAP 2020 user's manual.

  • Jaime Bonilla-Barbosa added an answer in Aquatic Plant:
    Can any one help me to identify this aquatic plant ?

    I have collected this plant in an fresh water aquatic pond

    + 4 more attachments

    Jaime Bonilla-Barbosa

    Hi,  the name of this species is Ceratophteris thalictroides. I sent information about the presente question, please not repeat.

  • Aravind Ravichandran asked a question in Enterobacter:
    How to increase the concentration of the bacteriophage(pfu/ml) in the given media?

    I cultured the Bacteriophage sample in the Enterobacter spp. grown on LB media. Pelleted down the Enterobacter after lysis and the supernatant(phage sample) has less concentration. for the further use for PCR and sequencing i need to increase the concentration of phage.How can i do that?How can i increase the concentration?

  • Jaskaran Singh added an answer in Quantum Cryptography:
    Which is the best Quantum Cryptography protocol till date?

    Which is the best quantum cryptography protocol in any dimension till date? please provide some numerical values regarding the error rate of Bob and information gained by eve...

    Jaskaran Singh

    Thank you very much Jesni...thats what I was looking for. 

  • Gurumoorthi Ramar added an answer in Hydroxyapatites:
    How to prepare Si samples for ICP-OES analysis?

    i prepared Si doped Hydroxyapatite powder. In that powder, how i will check the Si element?

    if i will go for ICP-OES or ICP-AES?

    incase i will go ICP_OES or ICP-AES, what are the procedure to make powder into solution?

    Gurumoorthi Ramar

    Thank you Etienne Laborde

  • George Stoica added an answer in Urban Planning:
    How do I divide traffic zones in a city which has a circular radial network?

    How to divide traffic zones in a city which has a circular radial network

    George Stoica

    No formal zoning will change (improve) the traffic. More importantly is how to monitor and coordinate the traffic. 

  • Shrestha Ranjit asked a question in CFRP:
    Why Carbon Fiber Reinforced Plastic (CFRP) composite material is weak when subjected to normal force?

    Why Carbon Fiber Reinforced Plastic (CFRP) composite material is weak when subjected to normal force?

  • A. Subba Rao added an answer in Soil Fertility:
    How can we proceed for decision on soil resource-based cropping sequence?

    Development of soil resource inventory of a given area , is considered highly imperative to take decisions on the options about the suitability of different crops in a farming system mode. At the same time, the information on edaphological requirements of different crops , is equally paramount , so that both are super-imposed in such a way, to delineate soil-crop analogues. This will pave the way for better land utilization efficiency. My further querries in this regard are as follows:

    * How should we develop a soil resource inventory ?. Shall we go for master soil pfofile stdies  or follow the grid- based soil sampling  coupled soil profiles to be later used for developing soil fertility variograms?. 

    * How shall we identify the soil fertility constraints of multiple nature from such soil resource inventory?.

    * What methodology , shall we adopt to identify   optimum soil requirement for different crops ?.

    * How should we identify the cropping sequence based on such soil resource inventory?.

    * Whether cropping sequence and land utilization efficiency are inter-related ?.If so , in what way?.

    I request my esteemed colleagues to share their experiences on these issues. Regards

    A. Subba Rao

    Dear Dr.Singh ,there is no limit for new developments in any subject but we have to build over or add strength to already existing knowledge base.Even with existing knowledge ,excellent work is being done from remote  North East part of India.We have to look .around and see what others are doing.I am providing reference to one good piece of work from Meghalaya. Land suitability analysis for orange&pineapple:a multi criteria decision making approach using Geo Spatial Technoly .Das,P.T. and Sudhakar,S.Journal of Geographic Information System,2014,6,40-44.Open access Journal.There are three more papers from North East apart from other references(16).

  • Jousheed Pk added an answer in Organic Reactions:
    Can anyone suggest a linker molecule other than mercaptopropionic acid?

    Hi, I am using 3-mercapto propionic acid for an organic reaction as co-catalyst (linker molecule). But it imparting some color impurities to my product and I want to omit it from my reaction. But if I am not using this the time cycle is more and yield is less. So I want to use some other linker molecule for the same reaction  instead of 3-mpa. Any one can suggest any other possible molecule. (The reaction is between 4-hydroxy acetophenon and phenol in presence of dry HCl to get 1,1,1 (tris hydroxy phenyl)methane

    Jousheed Pk

    @Abdelkader BOUAZIZ  and Xiaobo Gu: Yes, I can explain. The reaction is between 4-hydroxy acetophenone and phenol in presence of dry HCl. Dry HCl is first protonating 4-hydroxy acetophenon. Then 3-mercaptopropionic acid linking with its one end to protonated 4-hydroxy acetophenone and with other end to phenol. Because of this mechanism, the two reacting species are coming closer and reaction is speeding up. (Mercaptopriopinic acid has one end thiol group and other end is carboxylic acid group). So this is speeding up the reaction as well as yield also increasing. But the main problem, after the reaction, the product has little brownish colour because of the oxidation of sulfer from 3-mpa (most probably) and it is creating big issue. So I have decided to remove 3-mpa with any other linker molecules. That is why I am now in search of good linker molecule to substitute 3-mpa.  I hope the question is clear now and expecting your kind help. 

  • Guy-Armel Bounda added an answer in Therapy:
    What is your opinion on standarts in medicine for treatment ?

    Is the standart therapy the best therapy for each patient or standart therapy is only for military medicine ?

    Guy-Armel Bounda

    Personally from my point of view and based on my humble clinical expertise, i do think that standard therapy will be fit for each patient, but the revolution of medecine is moving toward personalized medicine therapy. The Military medicine is one the of the medicine which knows a fast growing progress due to its nature. However, standardizing therapy for each patient or for military medicine has various drawbacks. In conclusion, the standard therapy should be for each patient.

    Be blessed

  • Harry H. M. Hendrickx added an answer in Business Models:
    The Business Model Canvas: What theory could identify/explain its advantages over other business model approaches?

    The Business Model Canvas is tremendously successful. But what’s bothering me is the question of WHY?

    Obviously, good marketing by Osterwalder & Pigneur is involved (workshops, blogs etc.). However, this can’t be the whole story, right? Not so many people would use the Canvas if it didn’t have any value over competing business model approaches.

    I believe the success cannot arise from the choice of the nine components either. A number of authors have proposed business model components similar to those in the Canvas but did not have comparable success.

    Rather, to me it seems to be about the visualization (visualization = the "grid/matrix" that visually arranges the nine components). But then the question is: How does the visualization make the Canvas good/useful? And which theories could help to shed light on this? Is it possible at all to provide a theoretical explanation?

    What are your ideas concerning these questions? I am looking forward to any hint or suggestion :-)

    Many thanks in advance!!!

    Harry H. M. Hendrickx

     As regards the theoretical explanation I tend to believe that the wide acceptance and accessibility are an important aspect. It resolves and becomes a substitute for tedious convincing and conversation between stakeholders with different background and interests when a business c changes or new business arises. In my view te BMC has gained authority in large groups of practitioners a.o. due to its open evolution. My 2' cts

  • Miguel Oliva added an answer in Gender Differences:
    Is gender difference linked to employment barriers for youth?

    Is gender difference linked to employment barriers for youth? If yes, what type of barriers in Pakistan?

    Miguel Oliva

    It depends also on the extent of youth , i.e. cutting ages. In young mothers we also have children and family responsibilities factor affecting women's employment. In some social sectors that happens quite young. There is also the opportunity cost ; women in poorest sectors generally have less education and thus get a job that compensates leaving household and eventually chilldren is more difficult.

    More broadly , there is a long term and intergenerational process of social modernization with an increasing woman insertion in the labor market. Our great - grandmothers were less likely to have a formal work, and usually did not either study at the university. Nowaday the differences in this respect are less important. In a 100 years ahead, the differences are likely to be almost nonexistent.

    You may find some empirical evidence about women´s insertion on labour market in Argentina (in spanish) here:


  • Ahmad Zafari asked a question in Arrhenius Equations:
    Does anyone know the value of grain boundary mobility (M) in beta titanium alloys?

    Dear all, 

    Does anyone know an Arrhenius equation for the mobility of a high angle grain boundary (beta/beta) in beta-Ti alloys? 


  • Ag Pandurangan added an answer in Plants:
    Can any one help me to identify this speciemen?

     I have collected this plant from Anathagiri hills near Aruku valley of East Ghats of India.

    Ag Pandurangan

    Yes, The plant is M. trichocarpa .

  • Alain Manuel Chaple Gil added an answer in Dental Caries:
    Can anybody share experiences in manage of dental caries risk assessment in patients?

    I will appreciate a lot all papers you can share.... thank you in advance and best regards.

    Alain Manuel Chaple Gil

    Dear Ebingen,

    Thank you very much for your help and answer, there are really interesting papers.

    Best regards.

  • Wang Heng added an answer in Electrical Power Systems:
    Why, as we increase the switching frequency, must the power rating be sacrificed?

    How we can relate switching frequency and power rating of power semiconducting devices? i know its inverse. As we increase the switching frequency power rating must be sacrificed. But i want to know why??

    Wang Heng

    Dear Mr.Kamarajugadda

    To answer your question, it should be noticed that every power device used in converter has a specific maximum operating junction temperature(Tvjmax) which not allowed to exceed.

    As temperature raise is caused by power losses of the device and thermal resistance is almost steady in one fixed design, then max allowed power losses can be determined by  Pmax = (Tj-Ta) / Rthja .

    Answer coming:

    1. power losses is composed by conductive losses and switching losses

    2. increase switching frequency will lead to higher switching losses

    3. reduce power rating(load current) could reduce both conductive and swithing losses

    therefore there is a trade off between fsw and load current in Pmax to ensure the Tvj not exceeded.

  • Shital Phuse added an answer in Solvent Extraction:
    Which solvent mixture should be used in Thin layer chromatography as a mobile phase?

    I am going to do analysis of antioxidant activity of some medicinal plants, for that I should go through solvent extraction. I want to ask that should I use the same solvents for thin layer chromatography which are used for extraction of the plant material. Please help me out.

    Shital Phuse

    @Gorentla sir and Prosenjit sir, I am using Acetone as polar solvent and Hexane or Ethyl acetate as non-polar solvent.

  • Kai Wang asked a question in Grafts:
    How to perform nephrectomy without killing the mice?

    In T1DM model, islets are transplanted into the kidney capsule.

    "To confirm graft dependent euglycemia, and to eliminate residual or regenerative native pancreatic beta cell function, animals with functional grafts had their islet transplants explanted either by nephrectomy. Renal subcapsular islet transplant recipients were placed under anesthesia, and the graftbearing kidney exposed. A LT200 Ligaclip (Johnson & Johnson, Inc., Ville St-Laurent, QC, CA) was used to occlude the renal vessels and the ureter at the pedicle. The left kidney was  then dissected."

    I copied that from literature, Can anybody provide more details or video to help a new learner like me?

  • Shen Zhenghui asked a question in Particle:
    How can I determine substance distribution in a mixture compound?

    I mixed 5 known  ployers together,and they formed a particle, how can I find out which substances are in the core , and which substances are in the outer?

  • Tapan Mukherjee added an answer in Drug Interactions:
    How can we identify drug interactions in vitro?

    If I am treating cancer cells with the more than two drug. Then would it be possible that one drug react with another drug. So what would be possible methods to study drug interaction.

    Tapan Mukherjee

    Dear Nihal,

           As Sergey told you may check the effect of a particular drug at a time on the in vitro cultured cells and then check the effect of two drugs simultaneously. As Jeffrey told that when two drugs are administered simultaneously you may expect to observe either additive effect or antagonistic effects or agonistic effects. The problem is two drugs may interact with each other and therefore may also neutralize with each other. In that case you can check whether your drugs interacted with each other or not by ultraviolet electronic excitation difference absorption spectroscopy and chromatography-coupled voltammetry.  

  • Scott Longmore added an answer in Python:
    Do you use Python programming language in your scientific research?

    Do you use Python programming language in your scientific research?

    Scott Longmore

    Given the mathematical and scientific python packages such as Numpy and Scipy, graphical packages such as matplotlib and numerous other utility packages (datetime, re, HDF, netCDF4, grib, etc), python, particularly the anaconda and enthought distributions, has become extremely popular in the past 5 years or so in the atmospheric sciences. I use it for all my light to medium weight calculations, as well as command and workflow language for all my automated real-time processing.

  • Chi Woo Yoon added an answer in Calcium Imaging:
    Is Fluo-4 am reliable to measure nuclear calcium?

    I've been using Fluo-4 am (invitrogen) to image cytosolic calcium level and I noticed calcium level in nuclear is higher than cytosolic calcium.

    Can I compare the level of calcium between cytoplasm and nucleoplasm based on Fluo-4 am imaging?

    Chi Woo Yoon

    I can not compare cytoplasm vs nucleoplasm but at least I can say that there is calcium influx into nuclei using Fluo-4 imaging, right?

  • Ksh. Newton Singh added an answer in Big Bang:
    Are particles created from the energy released during the Big Bang? During expansion, does the energy continuous converted into matters?

    We have learnt from the big bang cosmology that all the particles was created after the big bang explosion. My question is that whether these particles was created from the energy released due to the big bang? If yes, the energy density must be decreases during the course of expansion as it is continuously converting into masses or matters. Again if it happens so, the mass of universe must be increasing with time or expansion.

    Please some give some light on it. I'm working on a solution of Einstein's field equations and I got an expanding solution with an initial singularity. As the time increase to future, its mass and radius increases. So I need to explain the increase in mass with time.

    Ksh. Newton Singh

    Thank You Javadi. Before the big bang, in my knowledge it requires the concepts of String Cosmology or Brane physics. If it belongs to String Cosmology, it is far beyond my knowledge. So I prefer to focus on Big Bang Cosmology.

  • Charles Francis added an answer in Geometry:
    What is the best introductory reference on Galilean geometry?

    i need to understand the definition of the Galilean space.

    Charles Francis


  • Alain Manuel Chaple Gil added an answer in Stomatology:
    What's the anesthetic technique that other dental schools teach for lower molars and premolars?

    Here in Cuba we teach Conductive Technique in three steps with only one puntion. We block in the first the buccal nerve, later the lingual and finally the lower alveolar.

    What do you use in your university?

    Thank you in advance for your answer.

    Alain Manuel Chaple Gil

    Hola Pedro,

    Very interesting the article that you cited... Thank you and best regards.

  • Thomas Nann added an answer in Graphene Quantum Dots:
    Why do we see a fluorescence intensity decrease with graphene quantum dot doped with silver nanocrystal?

    graphene quantum dot doped with silver nano crystals GQD intensity of flurescence degrease why? GQD/PbS  coreshell quantum dot  intensity of fluorescence increase why?

    Thomas Nann

    good response Vinod! Jaya, you need to figure that out by doing proper spectroscopy ;-)

  • George Stoica added an answer in International Relations:
    Hello everyone. What is the relationship between capitalism and world government theory?

    Political science, International relations

    George Stoica

    In spite of all its shortcomings, capitalism is no. 1 in the top economical systems; the other systems may sound better than capitalism in theory, but in real life, they failed miserably - like communism, for example.

    I expect my answer to be down-voted by communists and their friends, perhaps they are willing to explain why, in their opinion, communism is superior in real life.