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Questions related to Resistance
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Do you know vancomycin resistant strains of staph.aureus are becoming more common?
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And we have also recently found a new VRSA from south of Iran, you can find the preliminary report of this unusual strain at: http://www.ncbi.nlm.nih.gov/pubmed/23880172.
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I know half of that energy is dissipated in heat in the resistance of the charging pathway, and only QVb/2 is finally stored on the capacitor at equilibrium
I'm just going to lower the resistance of the charging pathway so I will get more energy on the capacitor , but why this doesn't work ?
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This is an old problem that puzzles many ...Usual explanation is 1/2 energy loss is in heat (i^2R) or radiated if R approaches zero. This is indeed not very appealing although mathematically it is possible to show this using limits. A similar classic problem is paralleling a charged capacitor C with another uncharged  capacitor C when we lose 1/2 the energy using charge conservation principle.
Consider, if it helps, that the capacitor is like spring, the energy stored in a linear spring is1/2 kX^2. No matter how fast the spring is compressed the stored energy is dependent only on the final state X ( and of course constant k). even if we think of an impulsive force (dirac delta  ). Similarly however  fast  the capacitor is charged (ie R is reduced ) the final stored energy on the capacitor =1/2 C V0^2. Some say there is a connection to Thermodynamical principles.. but the phenomena is  counter intuitive..
Hope it helps..
Cheers
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I have seen in papers especially on iron pnictide superconductor, the transverse resistivity versus applied field at different fixed temperatures is found to be negative and linear. one of such papers is attached...Can anyone give me a clear explanation?
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In a single-band model the sign of the Hall coefficient RH is determined by the sign of the charge carriers at Fermi surface, whether electrons of holes (see pp. 14 and 15 of the book Solid State Physics, by Ashcroft and Mermin); in a multi-band model, the sign is determined by that of an effective charge that takes account of the contributions of all the bands crossing the Fermi surface (see pp. 233-239 of the same book); some carriers will be electron-like and some hole-like and the sign of  RH is determined by a balance between the two type of carriers.
You may also wish to consult the attached relevant publication.
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1. ( low resistivity or high resistivity wafer )
2. ( P type or N type)
3. Criteria for selection of resistivity and type
4. What type of wafer is preferred for piezoelectric based sensor where silicon doesn't contribute anything except supporting material i.e. cantilever.
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The cleaner the wafer has to be and the larger the diameter needed for your application, the more expensive it'll be. If you require very low oxygen concentration or other special features that make production difficult, you'll also have to pay more for that, but in general Si is very cheap and one can get good 6" wafers for as little as 40 $.
You can get a general idea for the prices here:
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I have measured electrical conductivity of a material by using impedance spectroscopy (IS). The obtained data from semi-circle of Nyquist Plot is resistance (Z). I am wondering that can I calculate dielectric constant from this data?
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Dear Friends here with I attach my excel sheet for the impedance, modulus and dielectric calculations. kindly refer it. For more understanding you may refer my papers attached herewith.
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HI, i found that female ICR mice were resistant to DSS(2.5, 3 and even 5%) for induction of colitis, while colitis was induced in male ICR mice using 3% DSS. Does any one know the reason.?? It is because of ICR mice strand or generally female mice are resistant??
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Thank you for bringing this matter to our attention!. It is still a great help and a real pleasure to read your posts
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I have surface resistivity(ohms/Square) values for a materials used for thin film resistor fabrication. Is there a method where we can calculate electrical resistivity out of it?
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If  film thickness, t  is known, the bulk resistivity, Rho (in ohm cm) can be calculated by multiplying the sheet resistance, Rs by the film thickness in cm;
Rho = Rx t
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How should the duty cycle be varied to vary effective external resistance and how can it be implemented?
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Dear Yury,
Thanks for the reply.
I am having bit difficulty in understanding the circuit.
What I get is  ,the rotor terminals are connected to uncontrolled bridge which has been connected with Ld to reduce ripple content across an external resistance R105.
Through switching IGBT rotor resistance can be varied.
Net external  resistance would be Rnet= Rs+R105(1-k)   where k is the duty cycle
Please correct me if I going in the wrong direction.
Few confusions that I have are:
1)Why has the capacitor Ckdm been used?Do I need to use it with IGBT too?To what voltage rating an IGBT can be used?
2)I can not understand the function of VD7 , VD8, Lkom,TK,CY,...Please explain about them..
3)How is the controller judging the speed of rotor in  order to change the duty cycle to vary resistance?Do we need to employ a micro controller for it?Can you please explain the logic.
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I have an inverter and Siemens 3ph induction motor model 1LA7060-4AB10
I want to measure or estimate the parameters of this motor such as :
Rotor resistance
Stator resistance
Rotor leakage inductance
Stator leakage inductance
Mutual inductance
Using the input voltage and the currents
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Hi, You need to do open circuit (No load) and short circuit (Rotor mechanical locking) tests. But these tests require a variable AC voltage source, and besides the Voltmeter and Ammeter, you need to use a Watt-meter. In the no load test you apply the full voltage to the motor and leave it run freely while you take the readings. Whereas, in the rotor locking test, you need to lock the rotor mechanically, and can not apply the full voltage. After you lock the rotor, you need to set the voltage of the variable AC source to zero before you supply the motor. Having your meters already connected start increasing the voltage very carefully form zero up to reaching the maximum allowed current given in the name-plate. You will reach that amount of current at a very low value of the voltage, may be 6% of the rated voltage. But, be very careful as the motor will burn if you went more. the readings are voltage, current and power at no load and at locked rotor cases. Using AC circuit theory, the no load readings will give you the magnetization branch components, and the locked rotor test will give you the stator and rotor resistance and reactance. 
Hope this helps,
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resistance plants showing considerable HR reaction, suceptible its not the case? What happens to resistance with segregation?
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I still thought it might be because the cuttings have some morphological characteristics that make them resistant. As you say that medis the resistance reaction produced by the lesion diameter on the leaf upon inoculation, perhaps making anatomical cuts inoculated leaves and not, find something that will help explain ...
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We deposited alkali halide film on Aluminum (Al) disc and measure the resistivity of the film. We found very low resistivity (~ 1 kohm) and its may be due to Al disc.
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If you would want to measure a considerably thinner alkali halide film, say 10 nm thick, then Dr. Kumar's method might not work because of pinholes in the film that would lead to shorts. In this case, you can evaporate interdigitated contacts (like two combs) onto an insulating substrate, followed by the evaporation of the alkali halide on top. You will then be measuring many squares of the alkali halide in parallel, hopefully giving you a resistance low enough to measure with an electrometer.
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(ex. Ketoconazole)
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You may check the presentation of Lass-Floerl (see link), slide 23, which shows both, CLSI and EUCAST breakpoints. Best regards, Oliver
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I have some EIS data of corroded cast iron coupons in NaCl solutions. I want to model my data by taking into account two components. A charge transfer layer and a porous layer. For both of these components there would be a capacitive and a resistive effect in the equivalent circuit (EC) which are represented by a constant phase element (Q) and a resistant (R). I can understand why Qct and Rct are in parallel but I can't figure out why charge transfer components are in series with just the Rp? Please find the EC picture attached.
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Hi Farhad,
Equivalent circuit models are meant to have a significance to what is physically/chemically occurring in the cell.  In general for coated (oxide or paint) material with corrosion under the coating, the charge transfer resistance and associated Cdl all comes from current that must pass through Rpore to get to the surface.  The coating capacitance (Q in your model) is parallel to that entire circuit.  (Note the models also need to have value for the actual spectra collected, and if you only see one time constant it is not possible have any confidence in values from a fit to a 2 time constant model.)
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I want to know that from which site or field should we select the susceptible weedlines so as to evaluate the resistance level in any weed species?
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Hi Eajaz,
We collect seed for susceptible checks from non-agricultural areas with no history of herbicide use (e.g. public park, home garden, roadsides, other natural areas, etc.). This seems to work well. I think there are a variety of approaches you can use here, as long as you can justify that the check should be susceptible, I think you should be good.
Scott
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In the Electrochemical impedance spectra, I have seen many papers reporting an equivalent circuit and corresponding values for solution resistance Rs, double layer capacitance Cdl, charge transfer resistance Rct, warburg impedance Zw and Pseudocapacitance Cp. However, some of them are frequency dependent e.g., Zw. How can we fit EIS with fix values of all the parameters since in Nyquist plot all points are at different frequency?
Any explanation?
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I think that you misunderstood something. Fitting procedures in EIS use some electrical components in order to produce an equivalent electrical circuit that best fits/mathches your experimental data.
The values that you are refered to represent specific values of Rs, Rct etc which are characteristic for a Nyquist plot and not the latter values for every frequency.
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In some cases they are used alternatively.
What is the best definition of each one?
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Dear Pourkhaloee,
'Resistance' and 'tolerance' are the terms used to denote the ability of the plant manage the stress, be it biotic or abiotic. I liked the way  Mirzaghaderi has explained it. Let me explain it further:
Resistance is an absolute term where the plant completely immunize itself to a particular stress. This kind of situation are are observed in case of Biotrophic pathogen (pathogen needing live host to draw nutrient) infection when the host contain a resistance gene and the infecting pathogen contain its corresponding avirulence gene (see gene-for-gene hypothesis, guard hypothesis and decoy hypothesis for further understanding). Typical examples of resistance are observed in diseases like rice blast, linseed rust, insects like brown plant hopper infestation of rice etc. But it does not mean that tolerance can not be obtained in case of biotic stress.
Tolerance is rather a relative term and it is also man made to some extent. In agriculture, tolerance means the plant can be under stress (diseased/ infected/ or physiologically challenged) but the extent of loss does not exceed the ECONOMIC THRESHOLD LEVEL (an extent of loss which do not hamper the economic potential of the produce). Examples of tolerance can be found in case of sheath blight of rice (necrotrophic pathogen that draw nutrient from dead host cells), Yellow stem borer of rice etc. and all the abiotic stresses because these are complex traits are are governed by multiple factors. 
Do you remember our old school days? There were few teachers who did not even allow to revolve our heads during exams and also the were few who did not really mind a little whispering but certainly wouldn't allow to copy from others. The first case is of resistance and the later is of tolerance !!!   
Hope this would be helpful for you. Best wishes.
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Cell and plasmid both are G418 (Geneticin) resistance. So how can i select the transfected cell to make stable cell line.  I need to work in same cell line and same plasmid. so any answer is appreciated. Thank you.
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add in an IRES puromycin sequence and select them
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I am looking for a practical formulas and data to estimate the thermal resistance of a mechanical interface especially in a vacuum and/ or cryogenic environment.
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It's a tricky problem since contact resistance dépends so strongly on the condition of the surface, and its history.
There is a lot of data available in the revue Cryogenics, for example
but a rapid search will show up many others.
This paper gives some formulae:
also
There's loads more data out there but it's not easy to accurately estimate.
Good luck.
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I need the mi-RNA profiling of radio-resistant gastric cancer. How can I obtain it?
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Try NCBI GEO database
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It is observed that resistivity decreases drastically on crystallization. Is it due to change in band gap or mobility or both?
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Dear Dr. Maria,
You have mentioned that in amorphous semiconductors, Fermi level is within the band gap and at 0K there are no conduction electrons. This is same in case of crystalline semiconductors also as the Fermi level is almost in the middle of the band gap in intrinsic semiconductors. This does not explain the difference between crystalline and amorphous state of the same material. I think mobility of charge carriers decreases drastically in amorphous state due to absence of long range order. This is why conductivity is more in crystalline as compared to amorphous state of the same material. Am I right?
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It's also called adriamycin, abbreviated as Dox. Is it commonly used in clinical practice? Is there any resistance to this drug? Anyone who has some experience with this drug, please kindly share with me some of these details.
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I would recommend doing a dose curve for your drug to determine the most effective range for your treatment. The responsiveness to the drug is based on your cell line you are working on.
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many peoples are plotting cole -cole between z' and z'' and many others between M' and M'',,,,then the what is basic behind this? please can anybody help me in detail.
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Dear Dr. Punia:
Despite of difficulty of data interpretation, analysis of electrical behaviour of materials via small signal in alternate current called of Impedance or impedance spectroscopy has gradually expanded yourself.
The impedance of a sample is typically represented by Z* being a function of the frequency of measurement, in a conventional formalism Z*(angular frequency).
The impedance Z* or Z*(angular frequency) is a complex number, in this sense, as follow Z* = Z' + jZ". Z" represents the core of the impedance spectroscopy. If Z" is null, the Ohm's law is retrieved. But, Z" represents the fraction absorbed of the original signal to separate "charges" at a specific frequency that coincide with natural frequency of oscillation of a specific mechanism present in the material. In another words, when the frequency of measurement is equal to a frequency natural of oscillation of a charge configuration, a kind of resonance phenomenon occurs that increase the absorption of original signal, Z" reach to a maximum, that is observed as a maximum in the function Z" x log(f). In this sense, it is possible to say that charges were separated in highest extension, for this condition since that energy is not storage a relaxation phenomenon occurs, then at the frequency of peak, an relaxation occurs.
In abroad sense, for each relaxation frequency there is a semicircle centered on abscissas axis, Z' axis in "Cole-Cole representation". Therefore, at an electroceramic a specific relaxation phenomenon is expected at grain and another at grain boundary.
In a general way, is not possible, by the visual inspection, identify both semicircles since each relaxation frequency should differ of at around three orders of magnitude. See there are more complex cases, which a single grain phenomenon is identified while three grain boundaries phenomena are presents.
All above can be written with different words; however frequencies of relaxation ascribed to the grains boundary appears alway at low frequency domain.
A priori, therefore, relaxation frequencies of grain boundary should be lower than relaxation frequency of grain. Sometimes, some kind of doubt emerges about the contribution at low frequencies to overall response, since, as an example, grain boundary exists but electrode polarization can also exist.
See, the impedance can be transformed in several another functions. The most common is the transformation of Z* in Complex permittivity function and Electric modulus function M*, but there is wide set of them (functions)...I attached a paper authored by me, where there is a set of formulas showing this. Depending on the choice of the researcher, an imaginary component in a type of representation can be converted in real component in another; also if a transformation selected is reciprocal of another function witha component of small value can be transformed in one of great numeric value and vice-versa. In the paper "Catalysis Today 78 (2003) pp 529-538, I comment:..."M* = M' + jM". This formalism is particularly suitable to detect phenomena as electrode polarization..."
Please if and when necessary, any item of the paper in attach can be discussed in more details, e-mail me. I try to attach another papers but was not possible.
Kind regards
Marcos Nobre
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What is the relationship between the resistance of concrete and time, does with time  the stiffness of RC decrease?
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Concrete stiffness increases in time with its elastic modulus, as you can find in all the ACI recommendations, Eurocodes and others. This is related to the increasing strength during curing days. After a brief period of time (a few months from casting) this tendency becomes negligible. After that, shrinkage and creep effects reduces with time the overall stiffness; due to the theory of linear viscoelaticity of concrete with aging, it is possible to explain the increasing strains attributable to sustained loads with a useful expedient: the so-called effective modulus of concrete Ec,eff = Ec/(1+f(t,t0)) where f(t,t0) is the creep coefficient. For subsequent sustained loads applied in different times to the concrete structure it is possible to extend the theory through the so-called AAEM (age-adjusted effective modulus) method, for which a reduced effective modulus which considers the concrete aging is defined.
Summarizing: time-dependent phenomena as creep and shrinkage in concrete have an effect equivalent to a decreasing modulus of elasticity which is the interpretation of the increasing strain due to sustained loads (self weight and other permanent loads) even though cracking is not considered. In high-rise buildings this effect is significant because it concerns with increasing axial shortening of columns and cores. In a similar way it is important for bridges, especially prestressed concrete bridges. For more info you can read my paper and the related bibliography:
Simplified Procedure for Evaluating the Effects of Creep and Shrinkage on Prestressed Concrete Girder Bridges and the Application of European and North American Prediction Models
There you can find info also on the codes useful for the estimation of these phenomena.
I hope this can be useful to give a correct answer to your question
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For a same material, which of the following microstructures will exhibit relatively higher hardness and wear resistance and WHY.
  1. Planar
  2. Cellular
  3. Columnar dendritic
  4. Equiaxed dendritic 
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Dear Sunny,
I totally agree with Sergei's answer. In order to optimize the material it is necessary to understand the failure or fracture mechanisms. It can be anything from shearing to fatigue failure to brittle fracture (or more likely: mixtures of these).
A deeper insight into failure mechanisms by wear is provided e.g. in Microstructure And Wear of Materials by K.H. Zum Gahr, Elsevier, 1987.
Igor
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Can be use high resistive material for this application?
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Al foil is a typical current collector in EDLC with organic electrolytes. In spite of low Al resistivity, the collector cross-section and length should be evaluated and the Al contribution to the total EDLC resistance should be taken into account. NOTE: inner EDLC resistance can be very low, e.g., our 1200F cells have about 70 microOhm only. On the other hand, the result depends on EDLC design. For example, in bipolar technologies they can use a conductive rubber with much higher resistivity that aluminum (since the current flows NOT along the collector but across it).
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GIC realized inductor is showing angle close to 90 degree for particular frequency zone and that zone is varying depending on the resistances/ capacitances I used. But the correlation is not clear to me. Can anyone help me on this or cite the necessary literature/ books?
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According to my knowledge the real source of these restrictions are the non-idealities of the used opamps only.
That means: For IDEAL opamps the circuit (active L) works for all values of R and C.  However, it is true that the amount of deviations from the ideal behaviour can be influenced by resistors/capacitor values. But that is a known effect. Also for a simple opamp amplifier, both gain-defining resistors should be selected taking the opamps non-idealities into account (not too low and not too large).
Regarding the active L-simulation (GIC): Numbering the 5 elements of a GIC from Z2 to Z6 and choosing Z5=1/sC5 we have an active inductor. For this circuit, L. Bruton has shown that for optimum behaviour (less influence of the opamps limited GBW) we should use Z3=Z4=R3=R4.
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I have tried a variety of 'alcohol-proof' and 'alcohol-resistant' markers, but have not been satisfied with any of them.  Either the marker is not actually resistant to 70% EtOH, or the marker dies after a month of use.  Does anyone have a preferred fine-tipped, long-lasting,  EtOH-resistant marker?  Thanks!
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In our lab we use edding 792 paint markers. Work perfectly, totally alcohol resistant.
Look at the site www.edding.com
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Is it a chromosomical resistance or is it acquired?
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Hello Jocelin,
I invite you to read both articles, they will bring you a lightening bolts on Pseudomonas resistance against Tigecycline.
1- Oglesby-Sherrouse AG1, Djapgne L, Nguyen AT, Vasil AI, Vasil ML. The complex interplay of iron, biofilm formation, and mucoidy affecting antimicrobial resistance of Pseudomonas aeruginosa. Pathog Dis. 2014 Apr;70(3):307-20. doi: 10.1111/2049-632X.12132. Epub 2014 Feb 10.
2- Dean CR1, Visalli MA, Projan SJ, Sum PE, Bradford PA. Efflux-mediated resistance to tigecycline (GAR-936) in Pseudomonas aeruginosa PAO1.Antimicrob Agents Chemother. 2003 Mar;47(3):972-8.
Good read
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I want to test composite materials for fire retardation or resistance to flammability.  Also I want to know the procedure of any test from which, i can test for the above said properties..
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There are several methods for fire resistance or flammability. Depending on the materials and applications of the materials you might find different methods. From there you can find the procedure
- UL 94 would certainly be a good start, UL 94HB, 94V, 94VTM, 94-5V, 94HBF, 94HF or UL 94 V-0, V-1 and V-2 flammability ratings.
- Limiting oxygen index (LOI)
- Vertical burning test (VC)
- Flammability ASTM D635, ISO 3795. The flammability test is used to determine the relative rate of burning of self-supporting plastics
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Pd considered good contact material with graphene due to low contact resistivity. Usually, Pd/Au is used. However, deposition rates are not discussed in the papers. What is the deposition rate for Pd?
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I usually use a low deposition rate, around 0.5 A/s, which normally gives a very flat surface and doesn't heat up the sample that much. Hope this helps.
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At what chlorine dosage is bacteria resistant or tolerant to chlorine disinfection?
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It varies for different bacteria, tolerance depends on resistance of bacteria (try to differentiate between between bacteriostatic and bactericidal concentration of chlorine to your target bacteria, these decides the tolerance limits. You may see the appropriate chapters at the links.
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Hi all,
I deposit 500nm of pt electrode on alumina using sputtering deposition. In very bizarre happening, the pt in each electrode show 1MOhm resistance! when i anneal the system up to 600degree each electrode show 15Kohm resistance after cooling. When I anneal up to 700degree the electrodes show open circuit after cooling. I think something happen in crystallization or something like that? anyone have any idea about it? How can i deposit a better layer with much lower resistance using pt and sputtering?
thanks
masoud
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 my experience with Pt electroplating i can tell some thing-
1. some of the pt voids filled with alumina
2. oxide on platinum forming PtO onstoichiometric
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From EIS measurements, it is well known that if the coating system has a coating resistance (Rc) in the range of Gohm could be classified as intact coating system.
The question is how to classify the coating system in term of the parameters obtained from Tafel test?
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Ammar,
I agree with the comments of Stefan about your question.
I recommend you a revision of the following papers:
G.W. Walter, “A critical review of dc electrochemical tests for painted metals”, Corrosion Science 26, 39 (1986) and related with potentiodynamic polarization measurements, and specifically Tafel plots, V. Otieno-Alego, G.A. Hope, H.J. Flitt, G.A. Cash, D.P. Schweinsberg, “The effect of potential scan rate on the parameters used to synthesize anodic polarization curves”, Corrosion Science 33 (11) 1719-1734 (1992)
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How can I  determine the carbapenem resistance for Klebsiella pneumoniae by using cephalosporinns and carbapenem group members ? Is there a reference that illustrating discs distribution for this method?  
Thank you.
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Would there be a significant difference between using the bands or not, for the same exercise and if so what are the causes ?
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The key is to perform a comprehensive assessment of the individual's strengths and weaknesses and needs for his/her left side. Based upon a comprehensive analysis then a individualized program can be created that may or may not benefit from resistive band ex's. An anatomical region that typically is not addressed enough is the hip adductor muscle group. Thus standing adductor ex's may help.
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I'm researching on rubber or polymer resin which have the physical properties like high abrasion resistance and high temperature resistance. Any suggestion? Thank you.
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polyimides are usually high temperature resistant, Polyaniline start degradation at 426 degreeC. Silicones possess high thermal stability. It is required to make blend with inorganics or graphite etc.
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Hi, I am doing research in CNTs. I would like to know that how should be the solution resistance, charge transfer resistance and capacitance? (for supercapacitor application). The electrolyte is 1 M sulphuric acid.
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Depends on your purity of sample, if its sample is good but not a conductivity one
(1) you may get semi-circle with high resistance
If sample is not good and not conducting one means
(2) you may get linear line with high resistance, plenty of paper is available and you can refer my paper also
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I'm going to use Polarization resistance (PR)  & Tafel tests to measure corrosion rate of welds , Is it possible to get Corrosion rate-time relationship from these techniques?
Thanks
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 you can follow  polarization resistance changes with time
it is corrosion rate vs time
better follow ZRA
you balance the voltage difference between your weldment and the alloy of equal area with external voltage source like potentio meter with 3V battery cell
The current needed to make the voltage zero is galvanic current
the electrodes should have equal area
you can follow galvanic current with time
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Rs (stator resistance) Stator winding resistance, in Ohm
Ld-Stator d-axis inductance, in H
Lq (q-axis ind.) Stator q-axis inductance, in H.
Vpk / krpm Peak line-to-line back emf constant, in V/krpm (mechanical speed).
Moment of Inertia Moment of inertia J of the machine, in kg*m2
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Dear Sakhti,
You may find such data in the attached paper!!
Regards,
Mohamed
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number of earth hole,resistance of electrode Does anybody know earthing calculation for buildings?
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Dear Hamid!
The earthing system in a plant / facility is very important for a few reasons, all of which are related to either the protection of people and equipment and/or the optimal operation of the electrical system. These include:
Equipotential bonding of conductive objects (e.g. metallic equipment, buildings, piping etc) to the earthing system prevent the presence of dangerous voltages between objects (and earth).
The earthing system provides a low resistance return path for earth faults within the plant, which protects both personnel and equipment
For earth faults with return paths to offsite generation sources, a low resistance earthing grid relative to remote earth prevents dangerous ground potential rises (touch and step potentials)
The earthing system provides a low resistance path (relative to remote earth) for voltage transients such as lightning and surges / overvoltages
Equipotential bonding helps prevent electrostatic buildup and discharge, which can cause sparks with enough energy to ignite flammable atmospheres
The earthing system provides a reference potential for electronic circuits and helps reduce electrical noise for electronic, instrumentation and communication systems
This calculation is based primarily on the guidelines provided by IEEE Std 80 (2000), "Guide for safety in AC substation grounding". Lightning protection is excluded from the scope of this calculation (refer to the specific lightning protection calculation for more details).
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How can I back cross ToLcv allelic genes TY1 and TY3 into elite cultivar? Which would will give higher resistance?
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Hi Gaurav,
1. Ty1 and Ty3 are allelic and you want to backcross BOTH into an elite cultivar:
(1) You can first make a cross between a resistant line (Ty1/Ty3) and an elite line (-/-)
(2) Ty1/Ty3 x -/- : your progeny will have either Ty1/- or Ty3/- genotype
(3) Backcross Ty1/- several runs with the elite line (-/-) to regain elite line genetic background (select the exist of Ty1 allele after each backcross). Let's say the find product is Elite line Ty1.
(4) At the same time, backcross Ty3/- several runs with the same elite line (-/-) to regain elite line genetic background (select the exist of Ty3 allele after each backcross). Let's say the find product is Elite line Ty3.
(5) Make a cross between (Elite line Ty1) and (Elite line Ty3); select progeny with both Ty1 and Ty3 (Ty1/Ty3 genotype). Then, now you will have both Ty1 and Ty2 alleles in a specific elite cultivar.
There might be other methods to develop it.
2. Regarding which allele confer higher resistance, you need to do experiment to decide it. If there is an 'additive effect' presence, the elite cultivar with both Ty1 and Ty3 alleles should confer higher resistance than those elite cultivar with only Ty1 or Ty3 allele alone
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What is the typical value of the source impedance (source resistance) of practical voltage source?
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There is nothing like the impedance typical value of a practical voltage source. It depends upon voltage source implementation and technology. Maybe it will be equal to about 0,1 ohm, maybe to about 1 ohm etc. 
Details about photolithography mechanisms for ultra-thin films?
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I have several questions related to photolithography of thin films: (1)    For Lift-off patterning there are three methods of lithography. What are the pros and limitations of each, two layer resist approach, negative resist sidewalls, thick Resist (2)    In Optical Microscopy, decreasing critical dimension comes at a cost of also decreasing depth of focus. Why is this significant for non flat surfaces.
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I'm not sure if I understand your problem in the second question, but anyway: If the variation of the height of your sample throughout the field of view is in the order of the depth of focus or greater, you will not be able to have the whole field of view in focus at the same time (full field microscopy).
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A instrument housing has to be modified to be flame resistant (min. UL94-V-2). The process properties should be as close as possible to standard ABS. The main subsidiary criteria are the bending and impact strength which should be even higher than ABS.
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For your information, at the end of the post:
there are more than 1160 comments, in my opinion, very interesting. Most of them are results of researchrs' new idea in whole world in many fields.
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I came to know with increasing C-rate the battery capacity will decrease, whereas for decreasing the C-rate the Capacity increases. I read that with higher C-rate the resistance will increase thus capacity will decrease. Kindly explain more details on how the resistance increase in terms of chemical/electrical  perspective?
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Omitting details, the basic idea is the following. Battery voltage includes mainly 3 contributions: difference between chemical potentials of the electrodes (well-known equation ΔG=-zFE) and two electrical potentials of the double layers at the surface of each electrode. The potential of the double layer includes the equilibrium part and the part caused be the finite rate of the transfer of the ions between electrodes and electrolyte (so-called overpotential). Battery capacity is the amount of the transferred ions, so it is directly related to the chemical composition of the electrodes and their chemical potentials.
If we charge the battery to the same voltage at two different rates, the overpotential will be higher for the battery charged at the higher rate. Correspondingly, the difference between the chemical potentials will be lower (we fix only the sum of all contributions to voltage!) and amount of the transferred ions will be lower, meaning that the capacity will be lower.
As for resistance, the charge transfer through the double layers constitutes a big part of it. And the battery with high resistance will have slower rate of the ion transfer, which means higher overpotentials at the same charging rate. As a result, the capacity will be lower again.
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bacterial isolates preserved for about 3 years ,
the antimicrobial susceptibility will change or remain the same after 3 years .
if it'll change , the changing will be toward sensitivity or resistance.
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I would like to add that if you have a resistant strain of a bacteria and the phenotype is given by a specific coding gene, preserving it appropriately (at -80 °C) is the way to ensure that the susceptibility profile will remain the same, since generally changes in susceptibility and resistance are given by mutations and by horizontal transfer of genes. As long as the bacteria is kept frozen at -80°C and it is not multiplying, the resistance phenotype will not change over time.  If you are going to work with the bacteria, you have to make sure that every time the strain is taken from the stock at -80 °C and not subculture repeatedly to avoid mutations.  
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I want to test stone chip resistance of  painted panels. 
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Dear friend, very interesting question. I am interested to your question and will explain in detail soon (similar to my case). A bit hurry for this time, please remind me.
However, the easiest way is searching the related document by typing the keywords into google scholar. You will find some related articles.
If yet to find the articles, do not hesitate to let me know. InsyaALLAH I will help you in detail.
Good luck. Dr Zol Bahri - Universiti Malaysia Perlis
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Hello All
I am interested in modelling an Industrial Robot to do offline Programming to calculate the Energy consumption. Right now I am successfull in developing a model and generate the torque for various movements. i would like to use this Mechanical Torque to estimate various parameters like Input Power, Copper and Iron losses. Is it possible to do this reverse calculation procedure. Right now I have the following values of motor, stator Resistance, iron loss resistance, number of poles, inductance value and inertia of motor. Can the above parameters be used to estimate the values or the efficiency measure should be used to make the calculations. If so efficiency values are used what would be the validity of the results.
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Narasim,
Your listed losses are indeed what can be expected in a traditional way..
However there might be important losses in magnets and rotor yoke:
1) No-load because of slots changing reluctance B in magnets:
this can be evaluated by a no-load test (driving torque without current)
2) Load losses due to the field of slots.
It increases the equivalent series resistance of a winding: in an qualitative way ti can be measured with an RLC meter at 50-500Hz
3) Transformer action by PWM.
The magnets and yoke act as a short circuited secondary.
The model is an equivalent parallel resistance to the coil.
It can be estimated by an RLC meter at 20-50kHz.
Or while doing a no-load test wth PWM
Those losses may increase the normal expected losses by 40-80%
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for organic/inorganic schottky diode structure 
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Very basic description can be found in my recently published book "Basic Properties of III-V Devices - Understanding Trapping Phenomena" (Kassel University Press GmbH, 2014).
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Is it possible to have resistance less than 1
for example 0.5, 0.25.. or any fraction number
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Although the question is, perhaps, not as clearly posed or directed as it might, I think the following may be what is sought.  The values of the coordinates, (m,n), of any node on the grid may be any real numbers but the point is that, since the grid is square, both m and n must be integer multiples of the distance between adjacent nodes, say d, so it is really a question of scaling.  By making d the unit length, the coordinates become integer and the arithmetic concomitantly simpler and the likely reason that you always see integer coordinates.  (Of course, electrical resistance, if under discussion, between arbitrary pairs of nodes will, in general, be non-integral using Ohm's law, even if the resistance of the material is 1ohm/d.)
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While BCS theory's predictions like isotope effect are excellent, I could never completely understand what is the origin of zero resistance in superconductors according to BCS theory. Any advice?
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In BCS theory, coupled electrons called Cooper pairs occupy the energy range around the Fermi energy, Ef plus/minus delta, where delta is the superconducting energy gap. Due to the Pauli principle the electrons forming a Cooper pair have the momentum +k and -k. To "create" electrical resistance, a Cooper pair needs to be scattered, and this process needs free states to scatter into. Even if you destroy another Cooper pair, no two fitting free states are created, since only one of the electrons of the destroyed Cooper pair is removed, e.g. exited to higher energies. Therefore the scattering cannot take place.
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Different group report different changes. In my case, the resistance goes up. I intend to believe that the swelling effect of ethanol dominates this change. But I'm not sure about it.
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how do you expose your PAni to ethanole or methanole?
a) in what form is your PAni? (powder, pressling, film?)
b) ethanole / methanole as gas?
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Reducing internal resistance and external resistance of Microbial Electrolysis Cell (MEC)/Microbial Fuel Cell (MFC).
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To reduce the internal resistance of MECs/MFCs you have different options, both structural and non-structural: 1. decrease the distance between the anode and the cathode; 2. increase the surface of the electrodes available for biofilm growth; 3. eventually change the electrodes material to more conductive ones (and with higher specific surface); 4. increase the surface of the ionic exchange membrane (if present); 5. apply a MPPT system to follow the internal resistance (see attached publication).
To reduce the external resistance is only a mechanical operation. You need to select a lower resistance and apply it to the MFC/MEC system. In order to achieve the maximum electrical power production, you need to select an external resistance near the internal resistance of the system (see attached publication).
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There is a trend of using increased amount of third generation cephalosporins and may lead to the bacterial resistance.
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Yes it is. But for E.coli and salmonella the use of ceftiofur especially in poultry is a major factor for ESBL bacteria carried by people. 
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Generally 4 point probe method used to measure the resistivity of a thin film. Can anybody give queries: "is it possible to measure the accurate resistivity of a thin film with substrate". Thank You.
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Generally, substrate are highly insulating materials and their conductivity is negligible as compared to material of the films. In four probe method current flows through the material of the film rather then substrate. Hence , the voltage developed in other two probes is due to the film and not the substrate. This way we measure the resistivity of the thin film and not the substrate.
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Why is the Endo-Crown concept not widely used while studies showed a significantly higher fracture resistance and more retentive than crown over post and core?
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Dear Alaa, The cuspal deflection is a reality and we have to take this parameter into account as much as the patient occlusion. Having said that i think that the dogma you cited in your statement is not reliable anymore. Each clinical situation is different and moreover this dogma and these old principles were right many years ago. A lot of progress have been made. At the moment, the bonding procedures and the less invasive dentistry permit to perform partial restorations instead of full coverage. Likewise, we try to avoid to place a post which can trigger more problems than advantages. Of course it doesn't concern the most of clinical cases but we have to keep in mind that the crown can be sometimes avoided.  In case of wide cavity and if the occlusion is favorable, you can sometimes indicated a bonded partial restoration with a cuspal coverage (ceramic or composite only or overlay). Sorry not to be in accordance with evidence based dentistry regarding this topic but i believe that we have to preserve the dental tissues and unfortunately the worst enemy of the tooth is often the dentist himself. Finally, the dogma you cited is a good point for the dentist business but not necessary for the patient...but it's an other topic...
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I need a test data but not a theoretical derivation. If there are the test data, I need the reference.
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I do not have the information regarding the test data for the specific case across threaded joints.  However, it is not difficult to conduct experiments of your own.  You need good temperature sensors and accurate heat flow measurement.  The normal practice is to insert a thin high thermal conducting material such as aluminium foil between the two to determine the heat flow and without.  The difference gives the heat flow without contact resistance and with contact resistance respectively.  From the values u can estimate the contact resistance from electrical analogy.
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I made a hybrid device of Graphene and Ti/Al by e-beam lithography, I can't find the superconducting gap when I measure the I-V and G-V curve of this device. (ps: the contact resistance of each junction is about 10k ohm after we anneal the device, the contact resistance is about 3xxK ohm before we anneal it)
Thanks.
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Could be simply a resolution problem. Critical current of Al is rather small (around 10nA at Vg=0). Therefore, the superconducting transition region (around T=1.2K) can be easily smeared off by the surrounding noise. Do you employ any filters to enhance the signal? Another possibility is damaging of contacts during a too rapid cooling off the device (up to 300mK). Here is a link to a successful realization of a similar setup. Perhaps you can find some answers to your problems in that paper.
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I need to know whether we can extract parasitic resistance of N-FinFET using VisualTCAD after doing the 3D device simulations.
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This is a good a question and I hope you already found an answer. If so please share it.
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I need to calculate the plasma resistance in DC glow discharge plasma. So is there any formula for calculating this?
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first of all: please be more precise: n = 1015 ... what units? - per m³ or per cm³? is the length scale of lambda_D accordingly?
also do NOT mix up Te with TeV - the first is in Kelvin, the second in eV and you have to make the correct conversion first.
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I have an arabidopsis mutant transformed by pMAT137Hm vector. Does anybody know its resistance? Kan or Hyg?
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Hi,
kanamycin is used for plant selection (50 µg/ml), hygromycin for bacteria selection.
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In our Hall resistance measurement using PPMS DC resistance model with four probe method, we always encounter a problem that the resistance data randomly fluctuates, so we must remeasured a same sample many times and may have a relatively good data at some time,  strongly influencing the efficiency and cost. I want to know, if this problem was a previous problem in many groups and what the reason is? The electrode? we connect the Pt wires on the film with Indium by hand pressing . if sputtering electrode metal on the film and then connecting the Pt wires would depress the problem? Thank you very much! 
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If you continue to have contact issues you might consider first putting down a bit of Au and then using a silver epoxy on top of that to attach the leads...
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For my MA thesis I'm examining the effect of differing levels of coordination/interplay between simultaneous nonviolent/violent groups on ultimate movement success. Can I make the distinction that armed wings are affiliated with the nonviolent movement, whereas (at least at face value) radical flanks are separate organizations?
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Elizabeth (and Colin and Tom),
I would recommend Benedetta Berti (2013) armed political organizations, Baltimore, Johns Hopkins University Press.. This is a study of Hezbollah, Hamas, and the IRA and their political and armed wings. Berti does draw on organization theory and sociology to explain transitions. Armed Political groups do establish nonviolent affiliates when they need to expand their appeal. On a more general note, working within an established paradigm rather than attempting to establish new categories might be a more manageable target for a Masters thesis.
Good luck with your interesting work!
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Until now, standard triple therapy was the most useful regimen for H. pylori
treatment. However, CLR resistance became an achilles heel for the triple therapy. However, local antibiogram for different regions varies widely. New regimens are not suggested yet. What should we do for an area from which we aim to eradicate H. pylori, while we have no data on antibiotic resistance? Note that we cannot recommend use of various antibiotics against H. pylori due to the distribution of resistance!
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The 7-day scheme is unequivocally dead except for few "happy islands". A 10-day sequential cost is lower than 14.day triple therapy and shows less side effects. On the other hand I fully agree with the geographic differences which cannot make universal what happens in a single region. An analysis of this problem in the attached paper. Fimally, the comparison in Lancet between triple and sequential therapy did not have the correct sample size. This criticism is largely present in current literature.
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I have one gene cloned from pure culture of plant fungal pathogen. Now I want to characterized this gene using molecular methods for which I have few resistance and susceptible strains of the pathogen. The gene is playing vital role as a virulent determinant therefore, I would like to proof weather the gene is actually playing role in avirulence in my pathogen too. I am not sure how I can proceed or which molecular methods should to follow. Any suggestion would be appreciated.
Thanks in advance
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Dear Susann,
You are right, performing GUS or some other physiological experiments would be interesting to study. But I doubt about some experiments at initial stages with fungal strains. I guess first I must find weather my gene occurs in which strain i,e resistant or susceptible, or in both using DNA isolation from pure cultures. Later I must include some plant varieties (winter rape) too and test the expression of gene in plant using GUS assays or other tests. But for this I must include some plant species which are actually resistant/susceptible to this particular pathogen. I know some of them from literature and people in EU are working on them.
I understand the importance of modern techniques in such research and would like to include them but if there could be some possible ways to handle such condition I would prefer to adapt them.
Thank you once again for explaining
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According to Garratt's book, The Atmospheric Boundary Layer (1994 page 43), a drag law is a relation between the surface stress (or the surface value of the friction velocity) and external flow variables e.g. the geostrophic wind.
According to Csanady (1967, J.Atmos.Sci., 24, 467-471), a resistance law of a turbulent Ekman layer is a relation connecting geostrophic wind drag coefficient to surface Rossby number.
It seems to me that both laws try to do the same thing: to get a quantitative relation between the "forcing" of the outer layer and the "reaction" of the wall layer. The manner of obtaining the two types of law is the same: matching the velocity laws in the two layers in the overlapping region.
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The matching of geostrophic wind (Ekman-like) and near-surface log-laws is known as the Geostrophic Drag Law--it actually relates the 'surface' friction velocity and geostrophic wind for a given surface roughness, and is used in e.g. wind energy models. See e.g. Arya+Wyngaard (1974), or Zilitinkevich+Esau(2005).
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In many practical cases, one affects arbitrarily a constant value for Chezy’s coefficient. It is a physically unjustified approach, because Chezy’s coefficient varies with flow parameters.
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Is there work that looks at how students build relationships at home and then bring those relationships, or ways of doing relationships to schools, to teachers, classrooms and to other students. I am talking sociological research in the frame of Hall, Jefferson, Connell, Willis, Ogbu, Smyth - cultural studies. The research I am doing is around how students become marginalised at school, because of 'anti-social' (sic) practices. My interviews looked at relationships to authority at home and then around the issues they were having at school.
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Yes.. Funds of knowledge!!!! Got it
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Studying the relationship between surface and volume conductivity in several "antistatic" (resistance between 10^4 to 10^8) polymer compounds. The surface conductivity seems to be pretty low compared to volume conductivity. Would this be due to a lower max # of atom to atom contact in particles at the surface vs. in the body of the sample mostly? (I know the "pipeline" theory of electricity: larger path, so to speak, means higher conductivity but is there a more quantifiable approach to analyzing the surface and volume conductivity values?). Also, please feel free to comment on the term/concept of surface conductivity; there are those who argue that it is simply a mathematically defined concept and not an actual phenomenon (due to fringing effects of the electric field etc).
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You raise some good issues Megan, and I presume the resistance values you mention have units of ohms per square. The values of conductivity (or resistivity) measured under different geometrical conditions may be expected to vary differently depending on the mechanisms of transport (electron, ion). An insulating material may have very low volume conductivity and a higher "surface" conductivity because of facile ion transport on the surface. The balance between bulk ion and electron conductivities usually varies dramatically with temperature. From a physico-chemical perspective, it is natural for the arrangement of atoms, molecules, ions, and chain segments to rearrange at surfaces upon creation of surfaces. This rearrangement (relative to the bulk) is the physical basis for creating surface energy. This rearrangement is also basis for expecting transport along a surface to differ from transport through the bulk. These transport differences would be expected to yield fundamentally different surface and volume conductivities. Surfaces are generally less dense in atom, ion, or molecular packing, in addition to having no nearest neighbors above a surface plane. One can see how these differences may lead to decreased electron electrical conductivity in surface layers and increased ionic conductivity in surface layers. Both types of measurements can be influenced by "fringing" effects, and surface conductivity measurements (with wire electrodes) are necessarily impacted by such effects. Doing a series of surface conductivity measurements on samples of varying thickness should provide empirical insight into which of surface or volume conductivities is greater. If you can also do these measurements over a wide temperature range, you maybe able to discern dominating transport mechanistic features. Best wishes, John
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I have some data from my sulfonated membranes and need some help in interpretation of the data with regards to its resistance, conductivity etc.
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Which is the electrolyte? And the BIAS potential.
Moreover can you send me your data copied in a word page? I would need Z' Z" and frequency data. The least but not the last, which is the experimental procedure to obtain the membrane and which is the working electrode you are using?
Are you working with a three electrodes system, aren't you?Can you tell which reference and counter electrode you are using?
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I'm trying to create a cisplatin resistant cancer cell line, HCT-116. Does anyone know the optimal concentration that I must add to the culture? I started with 1μg/ml of CDDP. I noticed that the drug killed most of the cells, but the levels of ERCC1 have decreased.
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Steps:
* Determine IC50 and IC90 dose of drug for 72h treatment.
* Treat cells with IC90 dose for 24h.
* Replace the media with fresh media containing IC50 dose and maintain it.
(The shock will kill most of the cells.)
* Some cells (less sensitive to drug) will remain alive for long time. Maintain the cells in that concentration unless it start division.
* Once confluent maintain the cells at the same dose for at least 5 generations.
* Then increase 1.5 times of the dose and repeat the same.
* Keep on increasing dose slowly for some time (till 4-5 times of IC resistance dose not come). Once cell will reach that conc, it will start expressing its resistant proteins in a stable fashion.
* Then increase the conc. twice or even thrice the previous dose, and cell will remain viable.
Note: 1) Make stock at every stable stage (after stable resistance at that dose).
2) Addition of glutamate (natural autophagy inhibitor) in the media may help some time.
3) If cell size increases (twice of the normal size) do not use that cells and start with a lower dose and with fresh stock. Some increase of cell size is expected.
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The output of straingauge is millivolts , how should i select my wire to connect the lead terminal of strain gauge to amplifier
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The resistance of the wires should not be important. Take care for symmetry (electrical, thermal) to suppress common mode noise and thermoelectric effects. http://en.wikipedia.org/wiki/Strain_gauge
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Irrational prescribing of antibiotics is common occurrence and leads to bacterial resistance.
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Yes, the new generation antibiotics should be included under the schedule H1 drugs and restrict/ check the indiscriminate use of antibiotics. 
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I am trying to establish contact between two newly generated surface after failure in Implicit. For example, i have applied enough tensile force to break the part into two pieces and then compressed two piece to examine is there any contact between the newly generated surfaces. As you can see surfaces simply penetrate into each other without any resistance even though i have defined a general contact with All*self contact domain. Is there any way to be able to define contact in this condition? Your help is highly appreciated.
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All with self contact does not consider the newly created surfaces (or rather meshed elements forming new surfaces). To get around this you have to select all internal elements in 'slave' surface definition that should consist of all faces of elements - not only outer ones. This can be done by modifying your input deck. See Abaqus keyword ref manual for 'Surface' definition.
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The resistivity could be measured by four probe method or AC spectrum. What is the difference between the two methods?
For the four probe method, the probe could be attached to the sample with the way shown in figure 1 or 2. How to calculate the resistivity for the two different ways?
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Only two short further comments :
1. The 4 Probe DC R measurement (4PDCR) is an approximate method attempting to compensate for the potential drop across ,usually high resistance material-electrode interface. In order to get the resistivity of the material, the two potential probes-sample electrical characteristics have to be same/identical. This is never the case and therefore 4PDCR method is not a method to be used. The error increases with increasing resistivity of the material under test. In pure Silicon for example (resistivity > 1kOhm.cm), 4PDCR become useless. Marcos reference (Schroder) is a very good one for further information.
2. The ac impedance measurements (parallel plate sample geometry) are probably the most precise and reliable , when the task is to obtain value for the resistivity of material. The bulk and interface responses are in most cases well separated in frequency and once the bulk response is identified, the resistance of the sample is a value of the real part of the measured impedance in the frequency region, where the real part is frequency independent. 
I hope this helps as well
with regards
Petr 
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I am working on CFD simulation of volumetric receiver of solar thermal unit. I just want to know how should I calculate the porosity & inertial & viscous resistance coefficient for all the three direction in Cartesian coordinate system?
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It is better to assume that they are uniform and constant. You can calculate base on the formula available for different types of porous media 
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Simple current mirror with two transistor circuit is used as active load in Op amp. Please see Op amp  UA 741C internal structure( I have mentioned Op amp to avoid diversion from statement. let us discuss about the same).
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Dear Vaibhav,
To answer this question, you do not need to see any current mirror here; simply think of its right part (Q1) as of a common emitter stage... or even as of a humble transistor driven by a constant base-emitter voltage...
Then, looking into the Q1's collector, you will see both the resistances - the low static (DC, ohmic), and the high dynamic (AC, differential). They may be illustrated very vell on the transistor output characteristic.
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I prepared a ceramic material which is an high restive material, but after electroding its resistance is in the mega ohm.  what would be the reason for it? it is because it is highly porous? or any other reason maybe?
Thanks for yours valuable suggestion....
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Porous samples may absorb moisture and may increase conductivity drastically. Anneal your sample for two hour at 300 degree centigrade as ceramic sample may retain water molecules up to 250 degree centigrade.Even if the resistance does not come back go to x ray diffraction to find out other phases developed during electroding.
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Complex electrical impedance has real and imaginary part for resistance and reactance respectively. Modulus is usually expressed in ohms. What physical information is conveyed from modulus alone without knowing complex parts?
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If by modulus of electrical  impedance you mean the absolute value of impedance
|Z|=Sqrt [ Z1(w)^2+Z2(w)^2 ],
then nothing new is learned from this number that can not be learned from the real (Z1(w)) and imaginary part (Z2(w)). It is just another way to represent a complex number (in phase and out of phase part of the electrical response) and without phase angle, as pointed out by Antonio and Juan, you have only part of the response information. So , stick to the real and imaginary part of the impedance, all information is there ! You can of course display the given response information by performing some trivial transforms which brings you to electrical complex admittance Y (Y(w)=1/Z(w)) or to the complex electrical capacitance C (C(w)=Y(w)/i.w . There are some other quantities that are unfortunately often used, such as "complex dielectric constant" (term dielectric function should be used !) or electrical conductivity, but these quantities are often un-physical (they do not represent what they should, namely the two intensive material parameters) if a clear distinction is not made between bulk and near interface regions that are being  measured.
With best regards
Petr 
How to test praziquantel resistance in schistosoma?
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Do you have any ideas regarding conventional protocol and PCR based technique for the detection of praziquantel resistance in various stages of S. japonicum?  
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You can test in mice, with an easy protocol. Here is attached.
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How do I make aluminumized aluminum coating less resistive?
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Yes - Electrical Resistivity.
I read many reports of adding conductive additives in the pores of the coating to reduce this resistivity. However, looking for a proven solution with a heritage history in space environment without sacrificing thermal and optical properties
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Results of drug resistance for HCV in http://hcv.geno2pheno.org comes up with fold change/resistance factor. What significance have these fold changes?
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Hello Nadeem,
The fold change or resistance factor is the increase in curative dosage (for treatment and in vivo models) or EC50 value (when done with a pathogen in culture) of a specific pathogen strain, compared to the 'normal/drug sensitive' control. 
A practical example: if a patient would normally be cured by a standard dose of, say, 150 mg of a drug, but you find that this particular patient does not respond to the treatment and you need an  increased dose of 750 mg instead to effect a cure, the fold-increase is of course 5. Similarly, if a culture of malaria parasites, Plasmodium falciparum is normally sensitive to chloroquine at 20 microgram per ml as EC50, and you are testing  in parallel a strain isolated from a patient that did not respond to chloroquine and find that the dose-response curve has shifted to a new EC50 value of 200 microgram per ml, the resistance factor is 10. The EC50 value, by the way, is the value (concentration) at which the growth or viability of the pathogen culture is inhibited by 50% (Effective Concentration 50%). The resistance factor is an important indicator as to how severe the resistance phenotype is. If it is low, a cure may still be possible by increasing the dosage or treatment schedule. A high resistance factor probably means the treatment is no longer effective, at least for the strain or patient in question. It is important to understand that treatment failure with a specific drug does not necessarily indicate drug resistance. Drug resistance is defined as the pathogen becoming less sensitive to the drug, almost always through a genetic change. But a treatment can fail because a lot of other factors as well, for instance:
1. the patient is too severely ill already
2. the patient is immunocompromised and the drug relies in part on the immune system
3. The administration was faulty or the patient did not take the medication as recommended
4. The drug quality was sub-standard. Perhaps the storage of the drug was inappropriate, or the drug was old. There instance of deliberate falsification of drugs, especially in developing countries. Generic drugs are cheaper but not always of the necessary quality.
5. Simply, many treatments cure only a percentage of patients; there is a statistical distribution
Hope this is of use.
Harry de Koning
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Cavity expansion theory is one approach to explain cone penetration resistance rest in a uniform and elasto-plastic material that behaves as an incompressible mass. Normally it is applied to sand, soil and sieved mortar, but can we apply it to fresh concrete (containing aggregate)? 
Is there any thesis to fully explain penetration resistance is correlated to strength of materials?
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Behavior of fresh concrete when hardening is comparable to soil consolidation as defined by the log time method in the attached paper. This work might be helpful for you. 
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I typically see a change of around 1 MOhms when blowing once the patch electrode is in the bath. Why is that and which is the "real" pipet resistance?
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I would think that when the patch electrode is placed in the bath some of the external solution goes into the pipette through capillary action and what you are seeing as a change in resistance is the internal replacing the external solution. The patch pipette resistance is somewhat dependent on the ion composition of the filling solution for example I see a lower resistance with a KCl internal compared to a CsCl one with the same size pipette. I would think this is due to different conductivities of the ions involved.
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Did anybody come across on prevalence of urticarial in follicular lymphoma pts.
I have pt ,who thinks that his urticarial which becomes resistant to multiple antihistamines is manifestation of his dormant follicular lymphoma.
I will appreciate your help
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Many thanks. He has urticaria which he tries to control with few strong antihistamines.  If he has sever attack, when his body becomes covered with big rad patches he takes rescue prednisolone.
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If resistance is fixed in a DC circuit, can voltage still be controlled and changed from one value to another?
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If you use PWM, is not DC anymore. What do you mean by controlling the voltage? You can just change the current, as Mechkov said, but it all depends on your circuit.
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Substrate Material: HCHCr D2 steel:
I need suggestion on material, thickness and layer of coating to improve wear resistance with higher thermal and electrical conductivity.
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hi, I think graphene is a good choice to improve the tribological behavior of a material. As u know graphene is an electrical conductor and it might positively influence electrical conductivity of the material as well.
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What is the best measurement method to determine bulk concentration, resistivity and mobility of thin films?
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Dear Mostefa  the best measurement method to determine bulk concentration, resistivity and mobility of thin films is by four probe technique or Hall measurement.
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Each physicist knows something about the definition of "inertia" and its relation to "rotation". We know that it represents the resistance of a "rigid body" for keeping its first position after rotating. Can we use this definition for the " Fluids"? Can we say that liquids have " rotational inertia " too? Why or why not ?
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Moment of inertia  "is the inertia of a rigid rotating body with respect to its rotation". The simplifying rigid body assumptions that lead to the moment of inertia do not apply to fluids. The Navier-Stokes equations get very messy (as if they aren't bad enough already) when the fluid is rotating.
That said, one reasonable simplifying assumption is that a fluid in a vessel has a zero moment of inertia tensor about the fluid's center of mass. The parallel axis theorem dictates the moment of inertia about an axis of rotation that does not pass through the fluid's center of mass.
Example: Hold an empty heavy cast iron pot by its handle and spin it around and back, like a washing machine tub. Now put some water in the pot and do the same. You don't feel much difference because the water isn't affected much by the rotation. The water's moment of inertia about its center of mass is essentially zero in this instance. If, on the other hand, you swing the entire pot like a pendulum you will feel a big difference between the empty pot and the full pot.
This zero moment of inertia is a simplifying assumption. The assumption fails if the changes in the vessel's rotational state couple with the fluid's state. Ignoring that this is a simplifying assumption that is only conditionally valid can lead to problems. It did with STS-49 and the capture of Intelsat 6. The rotating fluid inside the satellite acted like a gyroscope and came close to tearing the robotic arm on the Shuttle apart.
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How do I compute the sensor drift?  I am using a resistance based sensor and is the drift can be related with the  stability of the sensor?
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Sensor drift refers to outside interference, output change has nothing to do with the input, do not need. Including the zero drift and sensitivity drift etc...
Zero drift can be described as: the input voltage is zero, the output voltage changes to deviate from zero. It is also referred to as: Zero Drift
Zero drift and sensitivity drift can be divided into the time drift and temperature drift. Time drift refers to under specified conditions. The slow change with time zero or sensitivity. Temperature drift is environment temperature changes caused by zero or sensitivity drift,
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When we measure the drain source  current by applying drain source voltage of graphene contacted MoS2 tranistor before annealing and after annealing, we observed significant decrease of contact resistance after annealing compare to before annealing. What could be the appropriate reason for this observation?
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Thanks for your answer. Yes I am interested.
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I am working on thin films. I want to measure thin film conductivity. I have some result about thin film resistance in (Ohm/square) Unit, which collected by Four Point (Jundel rm3-ar) analyzer, and i don't know how to convert this figures to (Siemens/Meter) Unit. 
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Using the Jandel 4 point probe assumes you are measuring a thin film with respect to the spacing of the probe points.  Spacing is typically 1mm so any film less than 0.1mm should be fine.  Also the wafer should be infinitely large.  As long as the wafer is greater than 25 x 25mm large the error will be small. Typically less than 1%.
To convert ohms/sq into S/m you need to measure the thickness of the film using a profilometer or an AFM.
conductivity (S/m) = 1 / (R x t)
where R is in ohms/sq
t is film thickness in m.
Example:  You measure 25 ohms/sq and film is 120 nm
conductivity = 1 / (25 x 120 x 10^-9) = 333333 S/m or 3333 S/cm
Hope that helps.
cheers
Rick 
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Recently, I fabricated gold heater of serpentine shape on polyimide substrate. The heater is about 50 nm thick and the substrate is 7 um thick. However, when I increase the voltage of source to 6V, the resistance raised continuously to 400 Oh. (under room temperature normally is 250 Ohm). This change can be irreversibly. When I apply even higher voltage. The resistance could be ten thousand Ohms. Obviously, the heater was damaged or burned. If I want to heat up a little drop of water, the voltage that could result in damage can be lower. I am not sure what I can do in order to heat up and without damage my heater. I used a IR camera to detect the temperature when 6 V is applied, it shows the maximum temperature to be 34C.  Thank you
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You can try to increase the thickness and width of your gold serpentine. This is called electromigration damage. Also the thermal conductivity of PI is quite low. You could modify it somehow to remove the heat more efficiently. The 33.9 C is an average temperature measured by the camera. Does the camera have enough resolution to measure local temperature rise at the length scale of your gold strip width?
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I have prepared BSCCO pallet, however, the prepared pallet shows resistance at room temperature in Mega ohms can anyone help me know the possibility where I can make the correction?
The prepared samples were calcined at different stages up to 800 degrees. We want to know how we can reduce the resistance in the material. Is oxygenation a solution?
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Dear Dinesh,
600 Ohms is still high.
The RT resistivity of Bi2212 within the ab plane is ~ 0.3 to 2 mOhm.cm
              depending on the O partial pressure
              [Yamada et al 2007 Physica C 460-2; pp 815-816]
The RT resistivity of Bi2212 along the c axis is       ~ 1 Ohm.cm;
              [Krusin-Elbaum et al et al 2003 Physica C 387 pp 169-174]
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The annealing temperature of 880°C in air could be too high.
It is likely that some partial meting of Bi2212 occurs.
Then the result depends on how slow is your cooling.
There could be also a reaction with the material of crucible.
What crucible do you use?
Cheers,
Mark
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In the context of Bt crops literature, Resistance is defined as a heritable trait conferring a pest the hability to overcome the control by the Bt crop. Several authors agree in that "insecticide resistance be defined as an individual trait, which is an inher- ited ability of an insect to tolerate doses of a toxicant that would prove lethal to the majority of individuals in the normal population of the species". Here there seems to be an equivalency of both terms, resistance and tolerance. Part of the literature suggests that resistance involves change in the proportion of susceptibles in the population, while tolerance should be reserved to the status of the population prior to exposure to the Bt crop. Crava et al (2013) state that "We used the term tolerance in the sense defined by Finney
(1971), to refer to a quantitative measure of resistance that is normally distributed among individuals within a population". Other literature use both terms interchangably. Any suggestions about finding clear definitions of these terms?
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Hi,
In my opinion they key between "resistance" and "tolerance", regardless of insecticide, is inheritable trait. If the insensitivity, no matter how small, is passed on to subsequent generations it is resistance. Unfortunately confusion has arisen as low level resistance has often been referred to as tolerance. Tolerance is simply the 'upper end' of the normal distribution of response to a toxicant.
Of course, the definition of resistance also keeps changing to add to the confusion!
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I'm trying to measure TEER of HK-2 cells cultured onto collagen IV-coated PET inserts of 0.4 um2 pores. Nevertheless, when I measure the blank resistance I get a value that I think is too high (about 365 ohm). Is there anyone who did this measurement before that got a similar value?
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Hi Vale, lets talk about your problem, maybe you should think about using another measurement-set-up. Just contact me, whenever you have time. Cheers, Juliane
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Hello everyone,
I'm not really sure if this is the right place to put this but I am a PhD student at Cardiff University looking at the fabrication of biosensors and I am at the end of my tether with an impedance problem nobody seems to know how to answer.
I have found, shortly after buying a new glassy carbon electrode, that my impedance spectra are starting to lose their correct shape during my experiments and I wondered if anyone had experienced this before and if anyone can help me with it?
As you know the impedance spectra are supposed to have a semi circular part and a linear (diffusive) part. At low impedance resistances the semi circular nyquist diagram forms correctly, however at resistances above 1000 Ohms the graph becomes linear, losing the semi circular section and becoming hard to read. An example of how the spectrum looks as a good and bad example are attached.
So that you know the basic procedure is as follows:
Clean the electrode using 3micrometer, 1 micrometer diamond polish and then 0.05micrometer alumina polish followed by sonication in water for 2 minutes then 0.5M H2SO4 CV scans for 45 cycles at 100mVs between -0.5V and 1.5V (done until a steady and repeatable CV is obtained)
Electrodeposition of a polymer.
Addition of a DNA probe ("good" example of impedance shown at this stage)
Hybridisation of DNA with complimentary RNA at 50 degrees for 1 hour (causes increase in impedance resistance leading to "bad" example)
Spectra obtained using 5mM K3Fe(CN)6/ K4Fe(CN)6 in 0.1M KCl between 10mHz and 10kHz at 5mV amplitude.
The "bad" example has only recently started occurring and is also visible after the deposition stage which is how i know it is only at high resistances. I have a feeling that this is due to the presence of two "surfaces", and therefore I am hoping that it is just a cleaning thing and not me needing another electrode (around £180 my supervisor wont want to spend).
Sorry for the long message but I am hoping that one of you might be able to help me with this issue.
Thank you all
Daniel Smith
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see my ppt -
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Hello,
I would like to know if its possible to measure the resistance from an IV curve. For a linear curve, its the slope which is straight forward. but for a non linear, for example a schottky diode type curve? I am currently performing an experiment with conductive AFM and I want to find the resistance from just the IV curves and eventually the conductivity (R=rho.l/A)
or is there any specific formula for the measurement?
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For a non-linear I-V curve the resistance is still defined as R=V/I. In contrast to an Ohmic behavior R is just not a constant. In addition, and because of the V-dependence of R, it is useful to defined the differential resistance R=dV/dI for non-linear I-V characteristic.