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  • Ponkumar Ilango added an answer in Natural Fibers:
    I want to compression test cylindrical specimens of fiber-cement. Is this possible? What is the standard use for construction and the test specimens?

    The cement is reinforced with natural fibers and I would like to make some preliminary tests to evaluate the resistance of the composite compression using different fiber content.

    Ponkumar Ilango

    Dear Joabel Raabe,

    Please , may not be 20 mm diameter by 40 mm length. The Standard Dimension of the Cylinder in IS 150 mm diameter X 300 mm height ,

    As Our Friend " Aman Kumar " has given the Details .   

  • Ito Fernando added an answer in Mites:
    What is the best media for Rhizoglyphus mite mass rearing? Fresh potato tuber or PDA?

     Prof. Zhang ZQ told me that potato is one of the best media for Rhizoglyphus. I already rear Rhyzoglyphus using potato fresh tuber, however i hate when the potato became rot and smell awful.

    Ito Fernando

    Thank you so much @Ariel Diaz. Its kinda same with Bot and Meyer's, isnt it ? Ill try to use it. Thanks.

  • Mohamed A. Husain added an answer in Knee Osteoarthritis:
    Are Physiotherapy interventions really capable to change the Pathology of Knee Osteoarthritis?

    Almost all the physiotherapy articles on OA  shows clinically significant in management osteoarthritis(Hip & Knee). Whether this significant changes are also capable of changing pathology of OA , so can we believe on each and every articles showing clinically significant ..............?

    Mohamed A. Husain

    Dear Mr Patel,

    Generally speaking, we as physiotherapists cannot reverse the degeneration process that occurs with OA (or aging in general). Allow me to explain the effects of each intervention separately :

    1. Electrical modalities: They are preferred by patients because they are effortless and numb the pain for a certain period of time after the session. The effect does not go beyond that.

    2. US: I don't think it is beneficial in this case. Just a waste of time. 

    3. Heat modailities: They are good to reduce pain and improve the circulation, which in return washes away the inflammatory mediators in the joint. It cannot reverse or stop the damaging processes however.

    4. Stretching exercises: A good intervention. The muscles tend to get shorter in length when not being used and due to the reduced ROM of the affected joint. Having flexible muscles reduces pressure on the joint.

    5. Strengthening exercise: These are the best. Strong muscles support the joint very well and improves the mechanics of mobility. Therefore, 'reduces' the abnormal direct stress on the joint surfaces.

    The OA process is a bit complex when you look at it from a mechanical point of view (ignore the histological changes for now). Degeneration leads to uneven force distribution on the joint surfaces, which causes wear and tear over time. This wear and tear exposes the joint surfaces leading to spur formation, inflammation and pain. This in return will lead to changes in joint mechanics and the whole cycle repeats itself again.

    By intervening one way or another, we try to break this cycle temporarily. Patients return after months because they stopped doing their exercises at home and because the condition simply got worse. It is as simple as that.


  • Empar Chenoll added an answer in Gut Microbiome:
    Why are 16S V4 directed primers giving higher Ct (lower amplification) in stool samples than Bifido specific primers?

    Ct values for 16S directed primers are higher than Cts for Bifido specific primers.

    Empar Chenoll

    Are there used for microbiota analysis by real-time PCR? in this case, as I suppose you know, the Ct found depends on primer-pair efficiency (not all PCR-protocols work similar). You need to focus on the quantification (by using the quantification curve), not on Ct values (that depends on each PCR efficiency), obtained with 10-fold diluted positive control PCR (for each primer-pair).

  • Mahdi Doostmohammadi added an answer in Linear Programming:
    Does anyone know the relation between a decision variable of primal problem and its dual problem?

    Considering the concept of linear programming, primal problem and its dual problem, I would like to ask a question which might be naive!

    I wonder whether we can represent a decision variable of the primal problem (for instance x_i) in the corresponding dual space (with respect to the data of dual problem).

    Any help or discussion is appreciated.

    Mahdi Doostmohammadi

    Thanks Boris for your answer.

    I have not found any answer to my question so far. Can you please let me know more in detail, considering a general problem, how (un)used resources and reduced costs can be exploited in order to find any answer to my question. 

  • Sahar S Dalahmeh asked a question in Clotrimazole:
    Which types of IS standards can one use for the analysis of Omeprazole, Pyrimethnamine, Clotrimazole, and Lumefantrine?

    Which types of IS standards can one use for the analysis of Omeprazole, Pyrimethnamine, Clotrimazole, and Lumefantrine?

  • Rooh Ullah asked a question in Experimental Diabetes Mellitus:
    How can I induce Type II Diabetes in rats?

    i want to induce diabetes type 2 in rats through streptozocin plus nicotinamide combination using cold saline 0.9% as solvent instead of citric acid buffer ???whats ur recommendations?

  • Mohan Lal asked a question in Health Care Services:
    How can we improve the health care services without big changes in the current system ?

    In most of the societies, small reforms are done to improve the health status of the people, but sometimes results are not up to the mark. Can you suggest some measures to achieve set goals for health?

  • Tom Verhoeven asked a question in Autophagy:
    While reading on autophagy modulation in CSCs, I've come across the term 'late phase glioblastoma stem cells'. What does 'late phase' mean here?

    I've come across the term twice now, and was wondering what the term means. Links to the article are attached. 

    + 1 more attachment

  • Senyong Chen asked a question in Abaqus:
    Why the result is different between abaqus standard and abaqus explicit?

    Hi all, 

    I run two simple simulations in standard and explicit based on the same FE model. The model is showed below. There are three parts in the model. One is a deformable body and others are treated as rigid body. Two rigid bodies are linked by a spring which stiffness was 720N/mm. The deformable part is controlled by displacement. The total displacement is 5 mm. Usually, the force applied on the deformable part should equal the spring force. I get a good result from Abaqus/standard. However, when I run the same model in Abaqus/explicit, the result is weird. 

    How could I solve this problem?


    + 3 more attachments

  • Ganeshlenin Kandasamy added an answer in Molecular Mechanics:
    How can I model Fe3O4 (111) surface slab with a ligand (like benzene) on top of the slab's surface?

    I want to model the slab surface of Fe3O4 (111) with a ligand (non-attached) to the slab's surface for DFT studies. Which software and detailed tutorials are available for this molecular modelling? 

    Ganeshlenin Kandasamy

    Thank You Dr. Kuznetsov.

  • Woohyun Shim added an answer in Choice Modeling:
    Looking for a study related to a seller's binary choice model: a seller's selection of a market with a fixed price or a random price?

    I am looking for a theoretical economics study that can illustrate a seller's decision when he needs to select one of the two options: he can sell his product to a market with a fixed price (moderate) or a market with a random price (extremely low or high). How can he decide which market to go?

    Other than explaining this using a simple risk preference approach, is there any theoretical study that explains determinants of his decision? I would be great if you can provide some suggestions.


    Woohyun Shim

    Thank you for you reply. I am well aware of the literature on expected utility theory and risk preference. What I wanted to ask was whether there is other approach that can explain a seller's decision under uncertainty (e.g., transaction cost economics). 

  • Vinayakumara D R asked a question in Ethanol:
    Any advice on the synthesis of tetra alkoxy chalcones with long alkyl chains ?

    I am trying to synthesis the chalcones using 3,4-dihexadecayloxybenzaldehyde and 3,4-dihexadecayloxyacetophenone in ethanol with basic condition, since both  of my non-polar ketone and aldehydes are insoluble in ethanol and methanol reaction is not moving, please suggest me one proper method

  • Harry ten Brink added an answer in Climate Change:
    Are there authentic published work confidently pinpointing the sole anthropogenic factors contributing to Climate Change?

    Combined natural and anthropogenic factors (geologically recent phenomenon) govern Climate Change. It is, therefore, of paramount importance to discretely recognize the role of humans in Climate Change and to plan efficient strategy to mitigate it.

    Harry ten Brink


    You make a big mistake Hansen is NOT participating in IPCC

    IPCC WG1 provides the Scientific arguments that climate has warmed in the recent decades warming and that it is highly likely that this warming is caused by the CO2/GHCs emitted by mankind. They also give an estimate of future warming.

    Where is the policy in the report(s) of WG1?

    Why do I ask you: you apparently did not read the report(s) not even the technical summary

    Also you are (too) stubborn to study literature on the temp trend that is of all places at the site of the greatest skepticist (Judith Curry). That is how science should be done.

  • Faisal Ali Mustafa asked a question in Crystalline Structures:
    Do differences exist between the thin film and powder materials XRD? What are the best methods for examination materials?

    XRD is a method to know the crystalline structure. The materials which be used in substrate deposition it is important to know some parameters about material such that lattice constant , dislocation density and strain.  

  • Oguzhan Ilgen added an answer in Zeolites:
    What is the CO2 adsorption capacity at 300degC for packed bed column containing 13X zeolites?

    I would like to know adsorption capacity up to 1 bar and high pressures (jPSA).

    Oguzhan Ilgen

    This study may be help you for first step. I can sent you by email.

    Cavenati, Simone, Carlos A. Grande, and Alírio E. Rodrigues. "Adsorption equilibrium of methane, carbon dioxide, and nitrogen on zeolite 13X at high pressures." Journal of Chemical & Engineering Data 49.4 (2004): 1095-1101.

  • Miranda Jane Walker added an answer in Classroom Research:
    Apart from questionnaires, are there other reliable ways of assessing school climate?

    Apart from answering this question, can you please recommend useful sources on school climate?

    Miranda Jane Walker

    Thank you Peter and Paul.

    Very helpful responses.

  • Reynaldo Gil-Pons added an answer in Directed Acyclic Graph:
    Is there a polynomial time algorithm for Poly-trees (Oriented trees) isomorphism?

    In terms of graph isomorphism complexity classes, Trees have a polynomial time algorithm and Directed Acyclic Graphs (DAG's) do not (so far).

    What about Poly-trees (oriented trees)? These are DAG's where the possible paths from a node are all trees. Unlike tree nodes, Poly-tree nodes can have several parents.

    Are polytrees in the isomorphism complexity class of DAG's or Trees, so far?

    I have posted this question in mathoverflow and math.stackexchange with no answers so far.

    Reynaldo Gil-Pons

    I think it is in P, by doing something like this (assume the polygraphs have n nodes each):

    1- Using any algorithm like DFS or BFS you can partition the polygraphs in components, each one being a tree (this can be done in O(n)).

    2- Then you have two sets of trees, and you must check if they are isomorphic. This can be modelled as a bipartite matching problem. Each tree is represented as a node, and two nodes (belonging to different sets of trees) are connected iff the corresponding trees are isomorphic (this can be done in O(n) + n ^ 2 * the time needed by the isomorphism algorithm)

    3- Then use a maximum bipartite matching algorithm like Hopcroft-Karp to find a maximum bipartite matching of the constructed graph, then its size is n iff the two polygraphs were isomorphic (this can be done in O(n sqrt(n)) ).

  • Mohd Yasser added an answer in SDS:
    2D-SDS Question: When running samples in the SDS dimension, why are they not migrating to the bottom of the gel and are instead stopping half-way?

    I'm running the gels at the recommended voltage and time. 2D-SDS Question: When running samples in the SDS dimension, why are they not migrating to the bottom of the gel and are instead stopping half-way?

    Mohd Yasser

    Allright, Since you have mentioned that you did not face any problem while running 11cm strip then it looks that all your reagent and protocol is allright. Now it looks as if their might be an an interuption in the current flowing to the gel during the run.. Please cross check the following things (this can be small things but some times it may be the reason for the problem).

    1. Check the level of the running buffer, that it must not drop below the platinum wire of your instrument (on the upper side) during the run. Sometimes it happens that Running buffer leaks in a very slow speed (dropwise) and after some time the level comes below the platinum wire at the upper side of your instrument. It goes unnoticed and the gel stops moving during the run. 

    2. Check your electrodes, platinum wires etc and wipe them properly.

    3. Can change your running buffer in between the run.

    Because, this 7cm Gel running instrument is different from your 11cm strip. so these could be the reason.

  • Sivagnanam. S asked a question in Pigment Analysis:
    Which nanometer (663, 645, 650, 510 and 480 nm) gives high absorption values in spectrophotometer in pigment analysis?

    Measuring leaf pigments analysis (Chlorophyll a,b and carotenoied) by spectro photometer at different wave length (663, 645, 650, 510 and 480) gives high and low absorbance value.  How?

  • Artur Braun added an answer in Electrodes:
    What is the electrochemical (Characterization) confirmation of CNT modified glassy carbon electrode (Except EIS studies)?

    Pls quote the reference What is the electrochemical (Characterization) confirmation of CNT modified glassy carbon electrode (Except EIS studies)?

    Artur Braun

    How would you do that with EIS?

    With you study charge carrier dynamics.

    At best, CV could give you a hint but even that sounds doubtful to me.

  • Benjamin Clanner-Engelshofen added an answer in Docosahexaenoic Acids:
    Is there any stain that facilitates fluorescent microscopic analysis of Docosahexaenoic acid in cells?

    Hello I am working on cell line and one of my compounds of study is docosahexaenoic acid. I wish to know if there is any fluorescent dye which can facilitate the fluorescent microscopic analysis of docosahexenoic acid in cells? I saw some research papers reporting staining with Oil Red O. Is it a good method to follow?

    Benjamin Clanner-Engelshofen

    Oil Red O (to my knowledge) doesn't selectively stain DHA. It is used to stain lipids of any kind. For that I once used BODIPY dyes, which are having a huge fluorescence.

    If you want to quantify DHA in the cell, you could used a normal lipid-stainig dye like BODIPY and afterwards extract all the cells lipids and quatify the amount of DHA in relation to the total lipids via gas-chromatography.
    also, if you have a very fragile cell system there is the possibility to use prestained lipide, like those:

    Also I once saw a paper using fatty acids with conjugated double bonds (more than 6 I think), that make the membrane fluoresce. Like here: http://www.ncbi.nlm.nih.gov/pubmed/778493

  • Alexander T. Morchenko 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?

    Alexander T. Morchenko

    The electromagnetic wave penetrates into the soil with a definite gradual attenuation as the distance from the source increases, so the measured signal is formed by 1) the medium volume without clearly defined limits, 2) the size of this volume depends on the properties of the medium. For example, the apparent electrical conductivity of soil, measured using the resistance or induction methods, is significantly affected by temperature and humidity. So talking about the volume of the medium is possible only with a certain degree of conditionality, if it’s correctly at all. Apparently, you can only estimate the size of the inclusions whose characteristics differ sharply from the rest part of the medium.

  • Zahra Aryan asked a question in Regression Analysis:
    How can I calculate or estimate the interactions of several variables to predict an outcome?

    Sometimes there are lots of variables which are related to predict an outcome and can be considered confounders of each other. So, regression analysis usually help adjust for these variables. 

    The situation will be complicated if 2 or 3 outcomes are related with other and happen together frequently. In this case, how can we accurately and scientifically estimate the interaction of independent and dependent variables?

    How can we find that " which independent variable is the strongest predictor of each outcome?

    thanks for your comments in advance

  • Chris Jordan added an answer in Mass Flow Rate:
    Measuring stream flow/velocity remotely: do any cost-effective options exist (loggers, drones)?

    I'm looking for advice on alternatives to measuring stream velocity and flow rates other than manual insertion of velocity meters. We are interested in tracking stream flows over time that our study populations of fish must deal with. However, because of the remote location of these streams, it is difficult to obtain data throughout the year. We use a variety of temperature loggers to measure temperature, and these work great. We are looking for a cost-effective way to measure stream flow/velocity remotely, across a large number (10-15) streams as well. any advice, suggestions are most welcome!

    Chris Jordan


    You can use pressure sensors to give you stage height logging.  You will need to be on-site to calibrate the pressure sensor at a range of flows (velocity profile of cross section at sensor), that way you can get Q from pressure.  You'll need two pressure sensors, one in the water for column height and one on shore for local barometric pressure (you can skip the latter if you have nearby weather station data).


  • Nawras H Mostafa asked a question in Silica:
    What are the issues regard using coupling agent in fibre-reinforced composites ?

    Hi everyone,

    I am looking for the disadvantages ( the mechanical ones) that related to use coupling agents in fibre-reinforced composites. As I found, there are two main problems arising from using such materials to enhance the bond strength between the matrix and the fillers (may be fibres). The first one is the degradation of bonding strength over time when the composites were exposed to wet environments. While the second one is that most coupling agents were used  for silica base filler materials, such as glass fibres, to activate the mechanism of coupling. Is that true? Any information will be highly appreciated.  Thank you     

  • Anna Kamza (Nowotnik) added an answer in Eye Tracking:
    What is the best way to calculate the index of cognitive activity (ICA) in eye tracking?

    Do you know any software?

    Anna Kamza (Nowotnik)

    I think Marta means whether we should do any additional calculations on the ICA data provided by BeGaze/Eyeworks or we should interpret it directly from the output file (for example just by calculating mean ICA from the specified time period)? In other words, we ask whether that data is raw and requires some further transformations or it is just ready to interpretation? We have got ICA in decimal values, but Marshall says about ICA values ranging from 0 to 20.... Hence we are not sure whether we should transform the ICA (raw?) data somehow (if so - how?)?

  • Mustapha Olajuwon Lateef added an answer in Phonons:
    How can we obtain k point for fcc, bcc and hexagonal structure for bands and phonon dispersion ?

    I have listed the k points used for bands and phonon dispersion of ZincBlende BN but it appear the dispersion is not curve (continuous) at the same axis on both plots. Check the dispersions are attached.

    0.00000000 0.00000000 0.00000000
    -0.25000000 0.25000000 -0.25000000
    0.25000000 -0.25000000 0.25000000
    0.25000000 -0.25000000 -0.25000000
    -0.25000000 0.25000000 0.25000000
    -0.25000000 -0.25000000 0.25000000
    0.25000000 0.25000000 -0.25000000
    0.25000000 0.25000000 0.25000000
    -0.25000000 -0.25000000 -0.2500000
    0.50000000 -0.50000000 0.50000000
    -0.50000000 0.50000000 0.50000000
    0.50000000 0.50000000 -0.50000000
    -0.50000000 -0.50000000 -0.50000000
    0.00000000 0.50000000 0.00000000
    -0.50000000 0.00000000 0.00000000
    0.00000000 -0.50000000 0.00000000
    0.00000000 0.00000000 0.50000000
    0.00000000 0.00000000 -0.50000000
    0.50000000 0.00000000 0.00000000
    0.75000000 -0.25000000 0.75000000
    -0.75000000 0.25000000 -0.75000000
    -0.75000000 -0.25000000 -0.75000000
    0.75000000 0.25000000 0.75000000
    0.25000000 -0.75000000 0.75000000
    -0.25000000 0.75000000 -0.75000000
    -0.75000000 0.25000000 0.75000000
    0.75000000 -0.25000000 -0.75000000
    0.75000000 0.25000000 -0.75000000
    -0.75000000 -0.25000000 0.75000000
    0.75000000 0.75000000 -0.25000000
    -0.75000000 -0.75000000 0.25000000
    -0.75000000 -0.75000000 -0.25000000
    0.75000000 0.75000000 0.25000000
    -0.75000000 0.75000000 0.25000000
    0.75000000 -0.75000000 -0.25000000
    -0.25000000 0.75000000 0.75000000
    0.25000000 -0.75000000 -0.75000000
    0.25000000 0.75000000 -0.75000000
    -0.25000000 -0.75000000 0.75000000
    -0.25000000 -0.75000000 -0.75000000
    0.25000000 0.75000000 0.75000000
    0.75000000 -0.75000000 0.25000000
    -0.75000000 0.75000000 -0.25000000
    0.50000000 0.00000000 0.50000000
    -0.50000000 0.00000000 -0.50000000
    0.00000000 -0.50000000 0.50000000
    -0.50000000 0.00000000 0.50000000
    0.50000000 0.00000000 -0.50000000
    0.50000000 0.50000000 0.00000000
    -0.50000000 -0.50000000 0.00000000
    -0.50000000 0.50000000 0.00000000
    0.00000000 0.50000000 0.50000000
    0.00000000 0.50000000 -0.50000000
    0.00000000 -0.50000000 -0.50000000
    0.50000000 -0.50000000 0.00000000
    0.00000000 -1.00000000 0.00000000
    0.00000000 0.00000000 -1.00000000
    -1.00000000 0.00000000 0.00000000
    -0.50000000 -1.00000000 0.00000000
    0.00000000 1.00000000 -0.50000000
    0.00000000 1.00000000 0.50000000
    0.50000000 1.00000000 0.00000000
    0.00000000 -0.50000000 -1.00000000
    0.00000000 0.50000000 -1.00000000

    + 1 more attachment

    Mustapha Olajuwon Lateef

    Dear Kai, I was able to identify the problem after several attempts, it was the high degeneracy in some high symmetry axis of the band structure that was a concern to me, which I felt was due to my choice of k point. I wish to inform you that it was resolved by setting the nbn  to old number (7,9,...)  to obtain the band structure. Any insight into the reason. see attached. I wish to fix the phonon dispersion too.

    + 2 more attachments

  • Manuel Morales added an answer in Gravitation:
    In GR, can we always choose the local speed of light to be everywhere smaller that the coordinate speed of light? Can this be used in a theory?

    It seems that many, if not all, solutions of Einstein's equations, such as black holes and grav. waves, can be given coordinates x\mu in such a way that the local speed of light is always slower than the coordinate speed of light. Think of gravitational lensing: the index of refraction of a gravitational potential always seems to be >1, in practical examples, so a gravitational potential slows light down, and never speeds it up (if coordinates are chosen carefully). This wouldn't be true for a negative-mass Schwarzschild solution, but that seems to be outlawed in nature.

     Now this was only a conjecture, I have not attempted to prove it. How would a rigorous mathematical theorem be formulated? And did anybody - and here I mean a wise person, not the average blogger - ever try to do something interesting with this observation? Like constructing a “hidden medium” for curved space-time?

    Manuel Morales

    As the unambiguous empirical evidence has shown, we cannot act in violation of the two laws that govern our existence (Final Selection Thought Experiment). So either we accept Nature on its terms and then advance science or we do not

    By learning how energy comes to exist and by applying such knowledge, it is my hope that we can collectively advance science instead of maintaining the status quo.

  • Hadi Maghsoudiganjeh added an answer in Nanotechnology:
    How can I get nanoparticles not to form nanoprecipitation?

    Hi, If nanoprecipitation method is used for the preparation of nanoparticles then on injecting organic phase into aqueous phase precipitates will be formed. My question is how to get discrete nanoparticles form these precipitates?

    Hadi Maghsoudiganjeh

    Hi, I think you get discrete nanoparticles in the solution. Do you want to separate one of them? You can deposit the solution on a glass slide using spincoater and let it dry. Then, if you look at it under microscope, you will be bale to see them separated.