NPTEL-NOC IITM · Transcript · · Updated
6. Incremental vs Transformational Research and Technology : Part 02 – Transcript
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Summary
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- Incremental research extends existing experimental or theoretical work to new values, ranges, or materials without altering the foundational framework.
- Transformational research involves discovering completely new phenomena or developing new techniques that dramatically change a field.
- Technology improvements can likewise be divided into incremental variations like tire treads and transformational shifts like the evolution of the smartphone.
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Hello everyone. Uh we were uh discussing this idea of research aspects and types. Uh in our last class uh we spoke about experimental research uh and we spoke about theoretical research. We also placed some context on you know where we are professionally and what that means with the kind of activity that we do. Uh so we will continue with this discussion. Uh we were uh discussing this idea about uh research being uh
incremental or transformational. Um incremental is not meant in any derogatory sense here. Uh it is still very important work. Uh it is just the manner in which that activity is happening. uh you can think of it as something that's already been done and it's being extended in uh certain directions. We spoke about this example of welding. Uh we also spoke about this example of studying catalysts. Uh in
both cases you can have um you know uh an experimental setup and a series of experiments which take new materials or new variations of materials and put them through the paces and then you uh understand what is the property of that material. What is special about its properties? How is it different from all the materials that have been studied before? um and therefore what is that unique uh application uh for which this
new material that you're uh you know synthesizing uh is very suitable for or maybe there's an application for which no other material was available and now you have created a a material that works so this is definitely very important work I mean there is no doubt about it um it's just that uh it is typically an extension of what was already available in some sense uh I would also add that this is these are two examples that I'm giving you from the uh uh you know
experimental world. We can also think of uh a similar situation in the theoretical world. Uh so you could think of um you know um uh x-ray extension of uh techniques to a new range of values or you know uh data points or a new system and so on. Uh so uh hall pitch relationship for example um is one example and I'll also talk about standard X-ray data for a system. Uh so
let's look at hall pitch uh for uh for a moment. Uh basically uh I mean you may or may not be a materials uh engineer but so this is just an example for you to understand what we are talking about. Uh so there is a as you are aware most materials have some strength. So there is something called a yield stress. So you start applying some stress and when you reach this point the material starts changing its shape. All right. So this is called the yield stress. uh what has
been discovered uh is that uh the yield stress depends on how the material has been made uh and what has in what ways it has been processed in some in more specifically what what exists with respect to its micro structure. So everything else being the same, composition being the same, crystal structure being the same. Uh you can have situations like what you see on the slide here. Uh you can have a situation where all of it is a single crystal in which case all the planes are in perfect
order when you go from left to right. Or you can have let us say here for example I have 1 2 so I'll put numbers here 1 2 3 4 5 there are five crystals here. uh in which case inside each crystals inside each crystal the planes are in a particular order but as you cross the boundary you see that the order is not the same when you cross the boundary from two to three uh the same set of planes are now oriented differently in two it was oriented this way in three it
is oriented the other way right so that is why it's called a separate crystal it's not called the same crystal so you have a situation where you now have five crystals here right and then uh you have another situation here where I clearly I cannot count here But uh the number of crystals but to give you an idea you have 1 2 3 4 5 6 7 8 9 so some you know some just under 20 in this direction about six in the vertical direction
you're looking at 120 crystals roughly approximately 120 crystals but you see the external shape is exactly the same right so if you look at whatever shape that has and this has they are basically the same so object wise when you pick it up in your hand they are exactly the same but internally they are very different and I will consider a situation where the crystal sizes are extremely small and so you cannot even see them so I don't know maybe there are a million crystals here right so 10^ 6 I just put a number here
maybe there are 10^ six crystals sitting here so um naturally as you increase the number of crystals and keep the overall dimension of that structure the same the average size of the crystal has to decrease you can see here this is one large crystal right this is the size of that crystal now suddenly it has become bunch of smaller crystals. So you can see the size is on average that size right. So that size is different here on average this is the size much much
smaller. So the size is decreasing and here it is so small that you cannot even see in this situation the last situation you cannot even see the uh crystal. So it is so small that is for for our visual observation you cannot see. So we associate this dimension that that I have marked here this dimension as a d so average diameter of that crystal. So this formula simply is uh uh telling you that the u the strength of that material
or the yield stress of the material uh is inversely related to that uh uh you know d power half or inversely related to the square root of the size average size of that material of the crystals in the material which basically means if you go to smaller crystal size the yield stress will be higher. Okay. Okay. So this is work it has already been done.
So a lot of work was done to create uh to understand that this is the relationship and then uh uh you know people use it a lot. You can certainly see a situation where uh people find new materials they get uh uh you know the uh crystal sizes of those materials and then they put uh put this equation to find out these constants. So this is a constant this is a constant. So sigma kn
is a constant and ky is a constant. So you get those two values and uh you can uh you know sort of predict the behavior of the material or so on. Um and you can uh if you had a new uh system where the sizes were different uh you could extend this relationship and see if this relationship will match for those sizes.
So clearly you have a range of values here. Uh you and maybe your initial set of experiments were in the middle. uh you can extend it to the higher end or the lower end uh and see if this equation holds um and if it doesn't hold maybe there's some explanation and so on or it changes then you have some two different slopes and so on. So you can take um uh the same equation and extend it outside its range and to the extent that that such work has not been done
before uh it is newer. Okay. Uh but you can see the sample synthesis is roughly the same uh the uh equation is basically the same uh and so on. number of factors here are roughly the same and therefore uh you can think of it I mean again like I said there's no hard and fast r tool here but you can think of such extrapolation to different size ranges unless you're seeing a completely new phenomenon in fact in fact they have done that that is significant work when
you when you see a complete uh you know change in the behavior of the material uh and you're trying to explain why it has changed uh why it is completely uh opposite of this prediction of this uh of this equation Right. Right. So, uh if you see that kind of a behavior uh you you can then you're coming up with new theories for it. Right. So, if you do that that is a very significant piece of work. But if it's all fitting the existing existing theory and you're
simply extending it to new set of values then to that degree this is an incremental uh uh piece of work. We can also look at uh you know XRD analysis. So this is a standard uh data for X-ray defraction of uh various materials. Um and you can see that you know there are uh without going into great details you will have a plot of intensity uh versus 2 theta degrees here
which is uh listed here. Um and uh you can do theoretical calculations of how a structure should be uh and then see uh theoretically predict its uh x-ray uh defracto uh x-ray defractometry plot x-ray defraction plot right so you can do that analysis you can think of maybe you have not yet synthesized the material you can try and do some analysis but the basic uh theory and you
can come up with these plots right so this set of plots you can come up with uh so but the basic theory uh you know the brag equation and so on is is essentially the same you are not really changing anything there uh you're just trying some new set of values um and maybe as an experimentalist if you had come up with a completely new material and it shows you some interesting uh phenomena and different plot that is very significant but if you're
essentially looking at for example let us say um you have a particular material that you're going to strain in some way So if you strain the material then it crystal structure say stays the same but it's uh you know the dspacing or the average interatomic spacing will change although the crystal structure remains the same in which case this plot will shift a little bit and you can calculate the shift and that is research you are
doing that research and figuring that out but fundamentally you have not done uh anything uh you know pathbreaking in some sense uh and if you're doing a sample which is strained you can compare your theoretical plot with the experimental plot and see if your uh values are matching. Right? So this is the uh manner in which this uh work can be done. You can maybe extra it only in one direction and not strain it in in other directions in which case maybe
some peaks remain in the same position but some other peaks shift uh right or left or whatever it is and then you can do some uh understanding of it. So again here the theory is the same. uh you're just working at some uh location with respect to the theory. Um and therefore you can consider or think of this as some uh extension of an existing work and therefore uh from purely from that
context you can think of this as uh a relatively uh incremental work. What I would uh what I want to emphasize here is again that this idea that something is incremental is by no means uh suggesting that it is trivial or it is uh uh you know not important and so on.
It is actually extremely important work and in fact uh uh the uh in some sense it is easier but your prior experience because you're used to seeing the data happen in a certain way your prior experience may push you in the same direction. So you have to fight that uh uh tendency and then explain your data in a uh you know appropriate manner. So uh that is what it is. What normally also happens is this is uh typically a
little um I would say you know easier to explain uh to uh others uh because uh it is an extension of something that already exists. So a lot of people other scientists, reviewers and so on understand the existing uh set of situations very well and so when you extend it it is easier for them to follow what it is that you're extending.
What is the difference that you're showing uh and how your work is new uh because you have now extended it past some point and so on. So they're able to understand it better. So generally a large body of uh the published work tends to be of this nature. a significant body of the published work will tend to be of this nature where you're extending uh uh you know on either side of some uh uh known situation.
Okay. And maybe the uh uh you know um difference is more uh visible when we look at the other extreme when we look at say something that is transformational. So when I say transformational research uh it means for example uh something like you have found out a new experimental technique or you're using a new experimental technique. In fact a lot of uh research often uh you know expands in a spurt
when a new technique becomes available anything it could be for right now it is AI. So you can now use AI in all kinds of situations right and then it suddenly changes you now have some very uh you know difficult equation suddenly being solved. So this technique is now transforming what we can do. Uh so that is transformational. Um but that is that is one example. I can give you some more examples of it which we will see. Uh we can also think of some new phenomenon that we have discovered. Again that is transformational. This is not just an