ResearchGate Q&A lets scientists and researchers exchange questions and answers relating to their research expertise, including areas such as techniques and methodologies.
Browse by research topic to find out what others in your field are discussing.
- How do the recent stoichiometric with three-way catalyst CNG engines perform on ultrafine PM emissions compared to older CNGs and 2010 diesels?
Recent publications, http://dx.doi.org/10.1021/es5005973, indicate lube oil as a major source.
The lube oil elements may not take so much fraction in PM, since the samples were collected after the TWC, some of the ultrafine particles were oxidized. TWC is rather effective on converting fine particles.Following
- How to avoid actinomycete growth interfering with the cyanobacterial purification process from soil samples?
I am using streak plating to isolate and purify cyanobacteria from microbial mats derived from rock samples. But I always end up getting actinomycete growth also on the BG-11 plates which outgrows the evidently green cyanobacteria on the plates. How do I just avoid actinomycete growth?Following
- Can APE1 enzyme form adduct with abasic site through schiffs base or any other reason?Kindly enlighten?
I see adduct when I treat my abasic site containing DNA with APE1 enzyme. what may be the other possible reasons? kindly help
Thanks in advance
- Which primer set is best for testing the different arbuscular-mycorrhiza species present in a commercial inoculum?
I want to check which species are present in a AM commercial inoculum containing spores, mycelium and root-fragments and after reading to Redecker, Kruger, Lee ... I don't know which primer set to select. Any sugestions?
I dont know the type of primer that you can use for but it is more easy to identify the species with morphological analyses of the sporeFollowing
- What are different methods for synthesis of esters of formylphenoxyacetic acid?
Formylphenoxyacetic acid undergo acetal formation in methanol in presence of acidFollowing
- What is mass? Why can’t matter exist without radiating gravitational waves?
I have no Masters degree in Physics. But I have this question and like to know, what scientists think. We all agree as a first principle that there is an attraction between any two objects having Mass. Newton succeeded in quantifying the force of attraction in terms distance between the objects and their masses.
As per Theory Of relativity gravitational force travels as waves: http://en.wikipedia.org/wiki/Gravitational_wave
If that is right, we still don’t know what is mass? But mankind knows proton and neutron have nearly equal mass, while an electron has a fraction of the mass of a neutron. Does mankind know what gives them the mass? We know string theory proposes, each may be a form of vibrating energy string. That means, different kind of vibration might be giving different mass.
In another perspective, the mass of a particle is attraction that the particle exerts on another particle having mass. Although laymen things mass determines the attraction, it is equally true that the attraction determines the mass. That is, if the distance from A to B is X-miles, then saying distance between B to A is X-miles is equally true. So we can say mass is resultant of attraction excreted (radiation or radiated) by a mater (instead of saying gravitational force is excreted by mass). That is, if there exists a mater that doesn’t exert gradational waves, it would have Zero mass.
For example, a huge body (made of matter) exerting no gravitational force would have no mass (so to speak). It can even pass by a black hole, as if nothing exist there. I believe, string theory trying to answer this kind of questions to solve this puzzle.
What would happen, if an elephant is hit by such huge body having a size of a bus and elementary particles of that body can’t pass through a body of the elephant made of electrons, protons and neutrons? Luckily in computer science we only deal with things much simpler than in the basic sciences.Following
- Is anyone familiar with matching between simulation and experimental part SPR?
Is there any acceptance number of matching between simulation and experimental part, sensor . how can I know this matching is accepted or not? what is the minimum limits of matching in Surface Plasmon Resonance?
thank you very much...100% help .... I will apply this for all my results it important to certified my Phd resultsFollowing
- How can one accurately model a 1/35.5 scale wing in a 'low speed' wind tunnel?
I have modeled the full sized kite in ANSYS-Fluent and now wish to use wind tunnel testing in order to validate the CFD results. The issue is that using 'Dimensional Analysis' I still come up with a model that requires the Reynold's number to be equal (Re_prototype=Re_model).
Does this mean that with a scale of 1/35.5, & CFD wind speed of 10 m/s, I must run the wind tunnel air speed at (35.5 x 10 m/s) i.e. 355 m/s in order to achieve equivalent Reynold's numbers?
The actual 'projected span' of the prototype is (7.096 m) & the max model size is (0.2 m), therefore I can't alter the scaling. Any help would be appreciated.
To artificially increase Reynolds number, people have employed trip strips in the past. Pick up some papers on it, and see what height you probably need to 'match' Re.
Other than that, the only viable option is a higher speed test or use a 1:1 scale for the part of the wing that is most important (not sure about this).
Or, you can run a 2D test and use various 3D correction equations to get appropriate 3D results.Following
- Why is fluorescence of H-Titania ( Black ) band gap of 2 eV showing a more intense peak when compared to white titania?
If Hydrogen is doped or substituted inside the titania it has to show low recombination rates for charge carriers. So for black titania intense peaks, it should become low like other broad peaks but it is becoming more intense than Pristine Titania. Why? It has to show less due to the low recombination rate in Black titania. So why it is more effective than white titania? Please see the ppt.
Nice question. Do you performed XPS analysis of these two samples? I think after looking into it we can find the exact reason.
Please have a look on attached articles.Following
- How can I calculate the gas pressure in a capillary when the flow rate is known?
How can I calculate the gas pressure in a capillary when the flow rate is known?Following
- How can I synthesize Fe3O4 nanoparticles by co-precipitation method?
Please suggest the most feasible method for this.
If you do not want to use nitrogen gas, you can try to use hydrothermal synthesis instead.Following
- Curcumin is an antioxidant or a ROS producer?
Most of the researchers are wonder about the dual activity of the curcumin.How it is possible for a compound to act as antioxidant(in normal cells) and ROS producer(in cancer cells)?
thank you Ru-Jeng TengFollowing
- How do I calculate an effect-size for a repeated meaures t-test?
I use an online calculator for between subjects t-tests, as my version of SPSS doesn't seem to offer effect sizes. I recolect checking what it did many years ago and it seemed to be accurate. So if anyone can point me to an online calcuator for repeated measures effect sizes, I'd be most grateful.Following
- If XRD peaks match with two crystal structure of a mineral ,How to explain the crystal structure?
I made zinc hydroxide/PVA composite. I did Xrd. Acording to JCDPS Some peaks match with wülfingite and other with sweetite.How to explain the crystal structure of Zn(OH))2.
Zinc hydroxide Zn(OH)2 has three natural mineral named wülfingite (orthorhombic), ashoverite and sweetite (both tetragonal).Following
- Why 18F- will combine with the Al-NOTA complex instead of combining with free Al3+? And why 18F- is not free in [18F]AlF complex?
Why 18F- will combine with the Al-NOTA complex instead of combining with free Al3+ in the method for 18F-labeling of peptides using [18F]AlF (aluminum fluoride) complex formation with 1,4,7-triazacyclononane-1,4,7-triacetic acid (NOTA) derivatives? And why 18F- is not free in [18F]AlF complex?
- Can anyone help with impedance measurement for brine partially saturated porous rock?
In attached figure, I illustrate a experiment scheme for measuring the impedance of a system of brine (NaCl+water) partially saturated porous rock.
We used the Solartron 1260A equipment and classical four-electrode method. The frequency was varied between 1e6 ~ 1 Hz.
As the figure shows, four ring-electrode (Ag) were attached on the surface of the rock.
After the experiment started, the brine was spontaneously imbibed to the rock sample, which was initially dry. During the imbibition process, the saturation of brine in the rock was increasing. The experiment purpose was to get the information of impedance variations relevant to brine saturation.
Here my question is after the rock surface between two voltage electrodes was immersed with brine. Does the measured impedance spectral represent the rock surface only or also rock interior? I am worried about that the brine immersed rock surface makes it is a short circuit; thus no inner saturation information from the impedance spectral.
Any advice and suggestions will be greatly appreciated.
Dr. Viscor, thank you very much for your answer and suggestion.
I do think by this way, the signal component of bulk impedance will become more solid.
I will test the suggested geometry soon.
However, this preliminary setting will be finally moved to an experiment with much higher pressure (12 MPa) . I need a test to see can this geometry bear such high pressure.
Attachment is a Nyquist plot of the results of recent impedance measurement experiment using the figure described way. We can see the changes in both real and imaginary parts with water saturation changing in the rock.
- Is it possible to store electrical energy as spring potential energy?
Is it possible to store electrical energy as spring potential energy? Can anyone please give me any link or paper showing any work in this topic? Thanks in advance .
Energy could change and transform from one kind to another, electricity may of coz be stored as spring potential energy.
However, you can not imagine how large will a mechanism be to store electricity, the highest quality energy. Think about the clockwork spring. You push the spring into full load, it would drive the clock only a few days, by contrast, two piece of 1.5V batteries would drive it for years.
If you replace the batteries by a spring, what the size will be?
I think it must be unacceptably large.Following
- What are the methods to identify and manage the New Product Introduction Risks in multi-tier OEM and Supplier environments?
The risks associated with new product introduction are:
1. Product related risk: the design and/or the production processes may be new to the production department.
2. Quality related risk: all new products have potential quality problems.
3. Market related risk: a new product may be technically elegant, but the market may not like it.
Additional risks for OEM:
1. Miscommunication between OEM brand owner and CM.
2. More complex supply chain means higher chance to make mistake.Following
- How can I find mechanical properties(Young modulus, poisson ratio) for a wood panel(1500*50*15)
I need to find some mechanical properties for a wood panel. Concerning Ex, Ey I thought to do a tensile test for both. Indeed I can make easily some samples in the panel. However concerning Ez I really don't how I can manage that with only 15 mm. If anybody has an idea knowing that I don't have a lot of machines(torsion, tensile, bending test).
Thanks a lot !
I am working with a solid wood. Here an example of panel. Do you think that could not work? Bands can be wider.Following
- Are the terms 'random' and 'probabilistic' of the same meaning? 'The notion of probability does not enter into the definition of a random variable.' (Ref.: page 43 of V. K. Rohatgi and A. K. Saleh, An Introduction to Probability and Statistics, Second Edition, Wiley Series in Probability and Statistics, John Wiley & Sons (Asia) Pte. Ltd., Singapore, 2001.) Here randomness has been defined in the measure theoretic sense.
On the other hand, it has also been said that 'A random variable is a set function whose domain is the elements of a sample space on which a probability function has been defined and whose range is the set of real numbers.' (Ref.: page 9 of J. D. Gibbons and S. Chakraborti, Nonparametric Statistical Inference, Third Edition, Marcel Dekker Inc., New York, 1992.)
One who is not conversant with measure theory would opine that a random variable must be probabilistic. But according to measure theory, a random variable need not be probabilistic, while a probabilistic variable is necessarily random by definition.
There should not be two different definitions of randomness. Perhaps a discussion is needed in this regard.
The mortality rates are not 'probabilities' although the rates sum up to 1.. Therefore I cited this example.Following
- Would you agree with me when I say phones are highly abstract abstractions?
When we say [r] and [R] in some languages are allophones we have to keep in mind that [r] and [R] aren’t realizations of sounds but abstractions, too. So /r/ vs [r], [R] symbolize only different levels of abstraction, but no individual sound. We have no possibility to WRITE a certain real-sound. The possible realizations are uncountable. So phonetics when using symbols like r, R, x or even compound symbols, with diacritics, like ø̞̈ (for the German ø) etc. is highly abstract. Like mathematics.
Realizations of sounds e.g., [r], [R] (i.p.a.) can be actually verified articulatorily and seen and measured acoustically. These are not merely at the abstract phonological level .Following
- Is it possible to predict vapor liquid equilibrium of binary mixtures with known excess enthalpy information ?
In our lab, we are doing experiments about the excess enthalpy of refrigerant and organic absorbent mixtures. With obtained excess enthalpy data at different temperatures, would it be possible to predict the vapor-liquid equilibrium behavior of the mixtures and how ?
- What is the effect of decreasing PH on concrete properties?
If we do something to decrease the PH of concrete after mixing and molding, what will be the result? is the PH important parameter in concrete properties?is there any paper about this subject?please explain.
Decreasing the pH level signifies the increase of acidity in the concrete. Thus, corrosion of reinforcement bar in the concrete will occur which degrades the concrete strength. There are few papers out there which discuss on the relationship between corrosion of concrete, concrete strength and even the effects in construction later on.Following
- What software is out there to analyse artery blood flow?
I currently have AVI files saved and exported from our ultrasound. I was wondering if anyone knew of accurate ways of analysing doppler flow signals from these AVI videos?
AVI files are usually a video capture from the out put of the scanner to the video diaplay. They are simple pictures and would not contain data re: velocities and spectral information.Following
- How much air do I need in Triptic Soy Broth tube?
TSB tube is supposed to be used for testing of presence of aerobic bacteria, yet it comes sealed with septum and stays sealed over the incubation period. Is the air dissolved in the media sufficient to support growth? Does the air in the head space of the tube matter?Following
- Is Corpus Linguistics an outdated field?
At university, we are updating our applied linguistics program. A colleague is saying that we should not include a course on corpus linguistics because the subject is outdated. Can you please advise?Following
- What steps might an organization take to develop a digital strategy?
A typical, not necessarily linear, methodology for developing a digital strategy is to (i) identify key business challenges and needs in the digital space translate objectives into actionable recommendations; (ii) evaluate digital products and services against requirements and develop new digital initiatives and plans to improve user experiences and drive value; (iii) collaborate with cross-functional teams to plan, deliver, and execute digital campaigns; (iv) educate and inspire personnel on digital opportunities, latest technologies, and best practices; and (v) ensure alignment between the digital strategy and the organization's overall knowledge management strategy. Can you suggest other steps and give concrete examples of digital strategies?Following
- How to calculate the mg Fe (II) equivalent/g of dry weight in case of FRAP assay?
Standard equation of FeSO4 is y=4.5682x-0.0347.
Different concentration used for the preparation of std curve are 60, 120, 180, 240, 300 mg/L.
I took 100ul of sample having concentration 1mg/ml and to it added 100 ul of water.
So, I used total of 200 ul of sample after assay reading were noted at 593 nm.
For my extract absorbance value comes out to be 1.567.
Now how to calculate mg Fe (II) equivalent/g of dry weight with this reading.
- please help
You must to dilute your sample in order to get an absorbance value that fits in the midle of the absorbances of the standard curve (e.g. if the 180 mg/L FeSO4 is 0,300 nm your samples must have absorbances around 0,3 nm). If the aborbances of the standard curve do not reach 1.567, you can not calculate the value of your sample.
After the diluition and assay, you have to substitute the "y" value in the given standard equation and then calculate it using the concentration of the sample in the assay. For example: If your initial concentration is 1mg/mL or 1g/L (you have to transform it to g/L, since your curve is in mg/L). Thus, you have 1g/L and you will dilute it 2 times, now you have 0,5 g/L.
Supposing that the value of "x" of your sample after the calculation with the equation was 190mg/L you must to divide 190 mg/L by 0,5g/L of sample and the result will be 380 mg FeSO4 by g of sample.
I hope that it helps.Following
- How can measure dye intensity or dye concentration in a real wastewater?
How can I measure dye intensity or dye concentration in a real wastewater? The real wastewater is a combination of different types of dye and other contaminant. I use an adsorbent for dye removal, its obvious that the color changed from black to a clear liquid after adsorption. I want to know how can I measure the dye concentration and color intensity after and before the adsorption using UV-vis?
Dear Professor Rastislav,
Thank you for your comprehensive response to my question. I will try this method.
- How do we normally sterilize hyaluronic acid solution?
Since 1% of this polymeric solution is too viscous to pass through a 0.22 micrometer filter. Anyone else overcome this problem?Following