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  • Seyed Hamid Reza Sanei added an answer in Composite Structures:
    How do I calculate the particle size and volume fraction of composites?

    Some article papers that I read about the AMC reinforced with particles, most of the authors write about the average particle size and volume fraction and it is associated with the microstructure.
    I'm tried to get the information how to calculate the particle size and volume fraction but did not found it.
    I'm not sure whether it can be found through the calculation or direct from analysis software.

    Please give some information.
    Thank You

    Seyed Hamid Reza Sanei

    There are two main techniques used for determination of reinforcement volume fraction namely 

    1. Matrix removal 

    a. Acid digestion 

    b. Matrix burn off 

    This method might not return accurate results depending on the nature of your reinforcement. 

    2. Image Analysis 

    This method is favorable as it does not require you to deal with acid and fire :) 

    It has also the advantage of determination of local volume fraction in addition to average volume fraction. Furthermore, other micro structural features such as void, reinforcement geometry, spatial distribution, etc. can be obtained. 

    There are many software out there, but you can determine all the microstructure features with a simple Matlab code. 



  • Evgeny Metelkin added an answer in Zero:
    Do you know how i can get inverse of a matrix that its determinant is zero or very near to zero?

    i model a shell in fortran code,and i calculate normal vector and deformation gradiant for it,but somewhere in the solution the z-direction of normal vector become so small and it cuase the determinant of defo-gradiant become so small and near zero and for inverse of it the element become so big and cause a problem,i want a way to avoid this

    Evgeny Metelkin

    Try ortogonalization using eigenvectors. The resulted transformed matrix is more easy to manipulate.

    Determinant is the multiplication of eigenvalues.

  • Artur Burzynski added an answer in Molecular Biological Techniques:
    Is there a problem with the Green and Sambrook recipe for a 10M Ammonium Acetate solution?

    A copy of what is printed in the fourth edition of "Molecular Cloning" by Green and Sambrook can be found here: http://cshprotocols.cshlp.org/content/2006/1/pdb.rec8067.full?text_only=true.

    I tried this protocol and had trouble. First, I tried adding 77g NH4AcO to 70mL H20 and ended up with ~135mL of solution (so it was already over 100mL). Second, it took ~10minutes to stir in the last bit of salt...adding more seems like it might take awhile to get into solution, if it will even go. Has anybody successfully made a 10M ammonium acetate solution using this protocol?

  • Amin Hodaei asked a question in Water Vapor:
    How can we plot 2D (P-T) phase diagram of water by projection of the intersections of the temperature-pressure-chemical potential planes?

    What are the equations of the chemical potentials of ice, water and vapor according to the changes of temperature and pressure?

  • Mohammad Mohajeran added an answer in Electromagnetic Induction:
    How we can determine exact volume of electrical conductivity measurements with electromagnetic induction method?

    when we measure electrical conductivity of a medium specially soils with electromagnetic induction method, we aren't unable to find out exact volume of measurements. is there any simple method to measure exact volume of this medium?

    Mohammad Mohajeran

    thanks to reply. in fact i developed an EMI (electromagnetic induction) meter to measure electrical conductivity of soil. i want to know what parameters are essential to measure volume of soil that have been effected by electromagnetic field. is it possible to calculate theoretically? and one more question. this EMI meter measure magnetic filed that induced in the soil as voltage.how can i calculate electromagnetic field from this voltage?

  • Marc Tessera added an answer in Cognitive Systems:
    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.

    Marc Tessera


    When there is no possible communication with a patient it is very difficult to make a relevant diagnosis and thus to know whether the patient is conscious.

  • Eric Hill asked a question in Storage:
    Does storage rat tissue samples for one week at -20 C affect on the sample?

    I stored my rat tissue sample in a box contain dry ice at -20 C for one week after that I noticed that dry ice was melt, then I transferred my sample to -80, I'm afraid that proteolytic degradation happened to my sample during storage at -20 C

  • Jonathan D Finn asked a question in Eukaryotic Cells:
    Is lambda phage DNA expressed in eukaryotic cells?

    A lot of people use lambda phage DNA as stuffer DNA for a variety of applications.  I was wondering if it is know if there would be any expression of the phage genes if the stuffer is used in eukaryotic cells?  Do phage promoters work in mammalian cells?



  • Shahida Shafi added an answer in Atherosclerosis:
    What is the best animal model to study atherosclerosis and how can atherosclerotic lesions be induced in as short time as possible?
    C57BL/6 mice would be better models to study or rabbit? Is there any standard method to study atherosclerotic lesions?
    Shahida Shafi

    There are two best animal models of atherosclerosis, rabbit and apoE knockout mice.

    Feeding high cholesterol diet for 4 weeks leads to the development of atherosclerotic lesions starting from aortic arch, to thoracic aorta and then in abdominal aorta. Feeding mice with high fat diet produces atherosclerotic lesions within few months and the lesions are distributed throughout the aortic tree. The advantage of using a rabbit model is that one can control the cholesterol level and obtaining blood samples. In the case of mice the plasma levels are difficult to control. Therefore, one has to think as to what question one is trying to answer and then decide on the model.

    • Source
      [Show abstract] [Hide abstract]
      ABSTRACT: Monocyte recruitment and their differentiation into macrophages are both early events in native and accelerated atherosclerosis that follows angioplasty. We have investigated the putative functional role of the epidermal growth factor receptor (EGFR) present on rabbit monocytes/macrophages. The impact of periadventitial delivery of an EGFR-specific, blocking monoclonal antibody (ICR62, which inhibits EGF-binding to its receptor) was investigated in a rabbit model of accelerated atherosclerosis induced by a combination of carotid injury and 4 weeks of a 2% cholesterol-diet. Two weeks after the initiation of the diet, a balloon-catheter angioplasty of the left common carotid artery was performed and a collar placed around the injured carotid artery immediately, for the delivery of ICR62 antibody, isotype-matched antibody or saline control. Monocyte/macrophage accumulation, cell proliferation and neointimal thickening were determined 2 weeks after the delivery of the antibodies. The function of the EGFR on rabbit monocytes was also investigated in vitro, using chemotaxis assays. Treatment with ICR62 was associated with a significant reduction in macrophage accumulation and neointimal thickening and a 76% reduction in neointimal area of the vessel wall compared with controls. In vitro ICR62 inhibited macrophage and smooth muscle cell migration towards EGFR ligands including EGF and HB-EGF. These findings suggest that EGFR ligation may be important in the development of early atherosclerotic lesions following balloon-catheter angioplasty, and periadventitial delivery may provide a feasible approach for administration of the inhibitors of EGFR-binding such as ICR62.
      International Journal of Experimental Pathology 12/2009; 91(3):224-34. DOI:10.1111/j.1365-2613.2009.00700.x
  • Filippo Salustri added an answer in Analogy:
    Is analogy the key to understand thinking?

    Hofstadter and Sander write in their book "Surfaces and Essences: Analogy as the Fuel and Fire of Thinking" that analogy is a key issue for cognition and perception. They put analogy into the center of all mental tools. I think analogy is a powerful tool but it is a tool beside others.

  • Marcileida Dos Santos added an answer in Google Analytics:
    Is anyone working with social media data?

    or using google analytics or other tools? any recommendation please?

    I am working with social media data, one of the chapter of my PhD. Facebook, Twitter,Instagram, Google +,Thumbl etc. I want to know the best way to gather my data. Thank you 

    Marcileida Dos Santos

    You are awesome!!!! Thank you x 

  • Diana Raie asked a question in Graphs:
    How can I convert a scanned figure into numerical data?

    I have a scanned curve and I want a software to converts an image file showing a graph, into numbers. 

    Could you suggest one? 

  • Mohamed Balbaa asked a question in Abaqus:
    In Abaqus, how to simulate multi pass heating in DFLUX?

    I want to simulate multi-pass moving heat source using DFLUX. I understand that I should use For loop but couldn't get to work, so is there any example or similar case to it?

  • Valentine John Belfiglio added an answer in War:
    Is it possible to have war without religion, or religion without war?
    Religion and mysticism are proto-ideologies, which can exacerbate existing national tensions
    Valentine John Belfiglio

    Hi Barry,

    Would you say there were no militants or religions involved in the Crusades or among ISIL?


  • David L Morgan added an answer in Mixed Methods:
    Any advice between a case study or mixed methods design?


    I'm writing my master thesis and have a bit of trouble with choosing method. The study is a follow-up study of QI-interventions. I'm using QUAN measures to see if the interventions lead to changes and if eventual changes were sustainable. Depending on the results of QUAN I'm going to do focus group interviews (QUAL) and try to find out what happended and why. So far so good (?). Now to my concern: is this a multiple case study or is it a mixed method study with explanatory sequential design? If this is considered to be a case study - what is the benefit of doing a case study vs "only" a mixed method study?

    Thankful for your opinions!

    David L Morgan

    Just to be clear, in mixed methods research, the main component does not have to come first. In particular, what is known as an exploratory sequential design takes the form: qual --> QUANT.

  • Allan Lindh added an answer in Applied Geophysics:
    Is it possible to calculate focal mechanism of microseismic event using single-array vertical borehole seismometer?

    I have a set of data recorded from single-array vertical borehole seismometer. We monitored the induced seismicity caused by hydraulic fracturing. I have identified and located the microseismic event, then we have 1800 microseismic events. Now, I am still working on calculating the moment magnitude to analyse the source parameters.

    The problem is I also need to analyse the failure mechanism that occurs in this study area using microseismic data. It is really important to analyse whether the failure mechanism is vertical dip slip, horizontal dip slip, or just an expansion (based on several references). I know that focal mechanism can be used to solve this problem.

    But, the question is, "Is it possible to calculate focal mechanism of microseismic event using single-array vertical borehole seismometer?"

    Have you met this case before? or Do you have another preference of method to analyse the occuring failure mechanism? Please kindly give me some reference. Thank you.

    Allan Lindh

    Dear Rexha

    Do you mind if I ask how far the cluster of seismicity is from your borehole array?

    And the depth of the seismicity, and the depth of your string?

  • Lotfi Zeghadnia added an answer in Computer:
    How to compute Lambert Function (W)?

    Lambert function has been proposed by Jean-Henri Lambert, some times called Omegat function (W).

    the equation can be written as following:

     xexp(x) = z  this means that x= W0(z)

    So the question is , how can i compute W0?

    Lotfi Zeghadnia

    Dear Mykola Kozlenko:

    Thank you very much for your response, is it available in fortrant or Qbasic, because i d'on't well known MATLAB language.


  • E. Oz asked a question in ALD:
    If the crystal growing succeeded in O2 plasma-enhanced ALD system, this growth, is also succeeds in thermal ALD system?

    When a crystal growing, is there a specific reason that using O2 plasma as reactants? If I using same precursor, can I achieve the same crystal growing in thermal ALD (using O2 or O3 as a reactant) ?

  • Fadi Abubaker asked a question in Authentication Protocol:
    I need simulation code for LEAP "Localized Encryption and Authentication Protocol" any help please ?

    i need the simulation code in any simulation tool 

  • Dominique Liger added an answer in Transfection:
    I want to linearized my plasmid (2ugr) with NotI, after that i will heat inactivat the enzym. Can i use it as it is for transfection?

    Do i have to precipitate?

    any one can help?

    Dominique Liger

    Hi there,

    Instead of enzyme inactivation I would suggest purification on column and elution in water or tris buffer. Transfection with linear plasmid will not give stable transformants unless DNA integration into host genome by double recombination event.

  • Jorge R. Ramos asked a question in Mica:
    How to dissagregate viruses for AFM study?

    Dear all,

    This is an AFM image of AAV viruses on mica, in air. I'd like to disperse/disaggregate them, so I can have a nice superficial distribution. Any suggestions?


  • Marcus Neuer added an answer in Hadoop:
    Has anyone deployed a multi-agent system on a Hadoop cluster?

    What i am trying to do is to test the two plateforms "Jade" and "Hadoop" simultaneously and i need to compare some results i had with initial tests.

    Marcus Neuer

    We are doing something very similar, involving Agents on an Apache Spark system. But the project progress is not far enough for having a publication yet. When considering Hadoop, I found this paper on an Multi-Agent Simulation:


    Hope this helps, yours


  • Tobi Popoola added an answer in Research Methods:
    How do you empirically/scientifically determine the number of moderator variables to include in a research/model?

    Hi RGaters,

    Thanks to everyone who contributed to my question on the difference between internal/external rewards and intrinsic/extrinsic rewards.

    Are there references on how/ways to determine (empirically/mathematically) the number of moderators to include in a management research? Is there a reasonable limit to the number of moderators to include in a model? I presume there is. How does a researcher objectively determine this limit? Or is the number of moderators included in a model subjectively determined.

    For example, there is a paper on control variable use in management research by Antic et al. (2011) which explains best practices for control variable use and reporting. Is there a reference on best practice on moderator variables use? Are there articles recommending best practices on moderator use and determining the number of moderators to include in a model or management research? 

    This question is not about understanding moderating effects as the answer to this question has already been provided by MacKinnon and colleagues (e.g. MacKinnon, 2011; Fairchild and MacKinnon, 2009), and several other researchers. I need to be able to scientifically support and justify the number moderators I decide to include in my model.


    Atinc, G., Simmering, M. J., & Kroll, M. J. (2011). Control variable use and reporting in macro and micro management research. Organizational Research Methods, 1094428110397773.

    Tobi Popoola

    Dear Soon, Kolawole and Mohd

    Thank you for your contributions.



  • Pyare mohan Tiwari asked a question in Sliding Mode Control:
    How the actuator saturation can be addressed in higher order sliding mode control design?

    In a higher-order sliding mode control design for a system with relative  degree two, how the system stability can be proved in the presence of actuator saturation?

  • Valentin Danci added an answer in Gravitational Field:
    Is the non locality of the gravitational field energy a serious problem for General Relativity (GRT)?



    "Although there is no room for such a thing in the energy–

    momentum tensor T, it is clear that there are situations where a ‘disembodied’

    gravitational energy is actually playing a physical role.

    Imagine  two massive bodies (planets, say). If they are close together (and we can

    suppose that they are instantaneously at rest relative to each other), then

    there will be a (negative) gravitational potential energy contribution which

    makes the total energy, and therefore the total mass, smaller than it would

    be if they are far apart.  Ignoring much tinier energy effects,

    such as distortions of each body’s shape due to the gravitational tidal field

    of the other, we see that the total contributions from the actual energy–

    momentum tensor T will be the same whether the two bodies are close

    together or far apart. Yet, the total mass/energy will differ in the two cases,

    and this difference would be attributed to the energy in the gravitational

    field itself (in fact a negative contribution, that is more sizeable when the

    bodies are close than when they are far apart)." 


    The same problem was also rised by Thirring, Kalman and Feynman in the FGT theory, they inserted the gravitational energy in the tensor equations...

    It is a problem of paramount importance which prevents the General relativity theory from describing any motion in which the hamiltonian is time dependent or rather in case of non isolated systems, or in case of non stationary interactions between different bodies.

    The attempt to model a free falling body in a gravitational field for GRT seems impossible.

    GRT has been tested  only for static or stationary systems where there is not a net exchange of energy (excluding gravitational radiation)

    Don't we need another GRAVITATIONAL THEORY which includes the results give by GRT in order to explain with a better accuracy the simple phenomenon like the free falling of a mass in a gravitational field?

    Valentin Danci

    No, nobody established by experiment that each and every equation resulted from Maxwell's theory has the same form in all reference frames. Again, on the contrary, it was Lorentz (et al.) who noticed a different form of Maxwell's equations, in the case of a moving frame.

    It was Lorentz' (et al.) unfortunate *decision* to make them appear of the same form for a moving frame. That means an unscientific distortion of the observations within that frame.  And that is not a correct way to establish a scientific fact.
    Even so, the damage was not that bad until Poincaré, Einstein and Minkowski decided to pile up even more guesses and assumptions on top of Lorentz/Voigt's mathematical trick.

    So that's the "establishment" of the relativity theory: a pile of guesses and "mathematical" fudging, decided on top of an unjustified mathematical trick.
    Stop glorifying that terrible mistake of the science of Physics.

  • Oleksandra Tiapko added an answer in Muscarinic Receptors:
    Has anyone had a problem with HEK293 insensitivity to Carbachol?

    Hi everybody!

    Would be very thankful if someone can help with a small problem!

    Suddenly HEK293 became insensitive to Carbachol stimulation in FURA experiments. With application of Carbachol no store-depletion is observed. Conditions are not changed, used the same buffers as before. Could it happen due to the lack of Muscarinic receptor? If anyone has ever had such problem?

    Thank you for any kind of suggestion!

    Oleksandra Tiapko

    Hi Timo,

    I did not try other stimuli because I need exactly Carbachol response. 

    Yes, Carbachol is ok. Passage number is quite low.

    When the cells stopped working, I thawed new one, but it did not help.

    Then the only suggestion was that we had inappropriate FBS, because the company stopped producing it and we had to switch to another FBS. So now we checked different FBS but cells still do not respond to Carbachol.

    I make the same buffers and split my cells in the same way as I always did.

    Will be very thankful for any suggestion! 

  • Soufiene Assidi asked a question in Accounting:
    What is the impact of tax information on financial performance?

    The connection between accounting and taxation in some context and the increase of tax burden present a motivations for manager to used tax accounting to influence tax due of firm. Tax information is important and it has  a significant influence on the performance of firm.

  • Bachir Achour added an answer in Trihalomethanes:
    Will anybody tell me the exact procedure of formation of Trihalomethanes (THMs) by chlorination of water or in wastewater?

    pleas tell me procedure.

    Bachir Achour

    Dear Anand,

    It is the reaction of chlorine with the aromatic organic matter, by substitution, oxidation or addition reactions. This resulted in halogenated organic compounds whose volatile fraction corresponds to trihalomethanes.

    With my best regards

    Prof. Bachir ACHOUR