 So, in the last lecture, we are looking at case study about microprinter and 3D micro fabrication and some kind of a technology for that and how mechatronics very you know elegantly helped us to realize that the goals of that 3D printer. So, today we are introducing some other case study where we are looking at this Helesaw based a system for very interesting way of fabrication ok. So, this is again invention at our lab the Suman-Maschwell Advanced Micronial Lab and with some patents pending on this technology also. So, I will tell you why we are looking at this technologies and what are the utilities for some applications as we go along ok. So, let us begin with the. So, this is the lab where this activity was carried out and we have seen here some of these micro 3D printing components that we have seen in the last class ok. So, there is a lot of collaborative work going on in this lab with different places and maybe I will have some opportunity to talk about little bit about that also. So, why we thought of like getting this new way of fabrication is based basically the inspiration is nature. So, in nature lot of systems you can see have this branches which are you know splitting branches ok. So, the trees has like this main branch splits into some branches and further they split into branches further they split into branches and this is there is some reason for such kind of a structures. If you see the mass transport activity or the heat transport activity you know these activities are very very efficiently done by these kind of structures ok. Say for example, in our hard circulatory system also we have this branches multiple branches and then split happens here and that is where the oxygen and carbon dioxide exchange happens for the lungs and then again these are brought back through some big size veins to the heart for pumping. And this pumping action whatever kind of energy that is required for this kind of a structures is kind of some somewhat optimized kind of a pumping energy ok. So, the nature has some ways to optimize this energy requirements for such applications by having geometry for the structures in the way it is there in the nature. So, we will say we are saying thinking like know this ok how can we fabricate such systems ok. So, these have very high efficiency that I was mentioning here. So, people have started like know fabricating this in a lab scale by on a wafer you know silicon wafer to do the similar study and they have found that it indeed this is kind of giving you efficient kind of a heat transport with the minimal energy of pumping of the fluid into these channels ok. These also have been found to be structurally more stable if you see the tree structures they are kind of stable structures for the different wind and other kind of a loading that is coming and people have started like using that also in the structural domain ok the civil construction kind of a domain. Where you have this multiple branch splitting happening to support the say ceiling or some other thing. So, you can see there are this more of such kind of a designs people they are also elegant in their artistic kind of a perspective. So, these designs have been coming up and they are now because of the 3D printing which is very ubiquitous now I mean and in the future also this is the way to go you can print these kind of a complex structures very easily ok otherwise without 3D printing fabricating such a kind of a structure is quite a task actually ok. So, there are some advantages to these structures and then the question comes ok why we how do we kind of manufacture such a structures in a very easy way ok conventional manufacturing techniques are there, but now we will see some different way of doing things here ok, but at not at the structure kind of a big scale, but as I say leave scale or some smaller scale than that ok. And then we will see how this you know some of the natural processes which are there can be exploited to do a good control over these structures and how mechatronics can play a very nice role in in whole process ok that is how we are going to develop this this talk ok. So, if you see this the inspiration is really from the from the natural phenomena ok. So, you can see this video where like you have this kind of a patterns that are coming in some kind of a way of painting like how this goes is you start off with this color palette here and then in this you have different colors you you you take to mix and like you know produce something and you add this glue to those colors ok you you put some kind of a favicol or some other kind of a glue and then like you make this slurry little thicker and use that in a on a plate ok whatever combination of colors that you want to kind of use you you may be able to use them and then you start placing under kind of a glass plate on the top of that ok. So, to squeeze these two things in in between the two glass plates ok. So, you you see that that that liquid is now pressed and it is formed into a film ok. So, you can see this somewhat circular film coming up there ok of the of the liquid color and favicol that that we have used ok and then you simply separate these plates out ok. When you separate them out you see this geometry starts coming up some geometry starts coming up. This is a fingering instability that happens called a Safman Teller instability ok and this kind of a geometry that is coming up on this thing that you can transfer to the paper ok. So, if so that is how like you can get very interesting pictures of of this kind ok. And so, this is how it is getting transferred to the paper from the glass and you you have some interesting geometry coming up there ok. So, this is a completely natural kind of a way of doing things ok. So, now, the idea here is to exploit this process called Safman Teller instability in this cell called lifted helix or cell for fabricating some interesting kind of a structures of of branch kind of a pattern. So, you understood the process that ok you have a fluid drop which is pressed between the two plates and then this is compressed and then we we separate it out. Now, instead of doing manually we want to do it of course, in a in a in some kind of a controlled fashion and for that we now need to design a mechatonic system to to carry out that operation ok. And what patterns right now evolve are kind of random branches here ok. Every time you do the process you may not be guaranteed that ok same pattern will come ok. In fact, the patterns will be completely different every time you you carry out that. Now, we we want to see that ok these patterns are are repeatable controlled in in some way and we want to know like know how do we execute this process with the mechatronics ok. So, like that we we will proceed to kind of see answer see answers to these questions ok. So, you also give a thought to this process maybe you you think now based on whatever you understood from the course you see ok. Suppose I want to carry out this what kind of a thinking I should do or. So, I would suggest you pause this video here and you know give your own kind of a design of mechatonic system around this kind of phenomena and see what comes to your mind and see then like know when you see the solution some some other things we may open up. So, so do that exercise it will be very important to do ok. So, so you have to see the questions like how do we do this process of squeezing and then opening up either like you know the angular kind of a way of opening up or or straight parallel way of opening up ok. So, this right now we have done whatever we saw in the video is angular way of opening up ok. So, how do we kind of carry out this repeatedly in the exactly same manner ok. What you think about what is the process or what is the kind of a mechanism, what are the actuators that we should use, what are the sensors that we will use and how do we control what is the control algorithm that you may have to think about. So, all those details you give a good thought to that and then like know we will see the solution ok. So, now I am proceeding ok you may pause and think and then come back. So, let us think about this mechatronics now ok. So, your process is clear that you have this plate drop now it is getting compressed and then you are separating the films angularly and this separation of these plates happening angularly is about some axis which is fixed axis and preferably it is at the surface of this other plate ok. So, that like know the action happens really nicely. So, this is what is a constraint from the design perspective that ok. We want to open up these two plates and this opening needs to happen such that like know one plate is as if it is hinged to the other plate. We do not have a physical hinge there we have these glass plates here and in the glass you know how you cannot produce the hinge very easily and repeatable and also this process to have a good control like this needs to be carried out very very slow ok. This opening happens at a very very slow speed we want to open it up ok. We do not want to kind of do it at very fast speed. So, to have that control these are like you know some design requirements you can bring out ok. As you do the process you will find that these are the important design requirement that you need to move it very slow and then we need to have this motion happening such that there is no like you know the slipping motion ok. It is only like opening motion happening there is no like no side wise motion happening ok or shear motion happening ok. So, again think about this part if you have not really thought about this before. Then what we do is to use this remote center motion mechanism ok. So, there are many different remote center mechanisms that are available in the rigid domain rigid body domain use you check out in the website and see what are different kinds of rigid body you know remote center of motion mechanisms available and we can one can employ them here for this process. The which will work which will work for this process well, but to move it move things at slow speeds we will have a joint friction ok. The friction in the joints of this RCM mechanism rigid body RCM mechanism and if you want to move slow with the friction it is very very tough to do you know that right. We have seen that the friction model like you know when you start you want to move something which is very very slow speed it does not the things does not move they will just slip and then again they you stop and again we use some force exceeds then like you know it again slips like that if the stick slip kind of a phenomena will happen if you want to move very very slow speed ok. So, that is that is a problem with the friction. So, now how do we overcome this problem? So, then again like we have seen if you want to have very accurate motions without friction you need to think about these motions without having this rigid mechanical joints ok. So, without joints if you want to have this motion the option you remember what we have seen in the class is the the the compliant mechanisms. So, flexure mechanisms is what you will think of using and then you need to kind of say ok oh look are there any compliant mechanisms which can do this job available in a literature then you may find some things you may plan and use that. So, we have designed in this case our own compliant mechanisms here ok. So, you will see in a minute how we have done that ok. So, this is how you start this process of you know design of this kind of mechatronic systems in by using some of the ideas and concepts that we have learnt in the course. So, we want to get this very slow motion and then that is why we are using this compliant mechanisms in the system and then we will now use this first see the compliant mechanism and then build system around that then ok. So, this is a compliant mechanism is very simple it is like a simple cantilever link with this kind of a perpendicular fold to that link here and that is used as a as a as a compliant mechanism for this remote center motion. So, if you do the analysis of such a beam when the force is acting on it by using some standard softwares which are available in the market and see source or reverse or some FEM softwares then you will find that this mechanism ok. We did not do that before we just like know conceived this idea that ok. Let us say if we can use a cantilever for this purpose and then we started playing around and then we found that it is possible that this is this can be used because you know if you do this analysis you find that there is a point which is not really the hinge point of this cantilever which is somewhere outside in the space around that point actually the motion happens as if it the end point of this compliant link is moving around a circular arc about this center ok. So, that is what you will see some literature also like know some indications are there of such a kind of a thing, but there is in the literature it is only for the cantilever, but we are using now cantilever and some kind of you know additional link which is this is fold of the cantilever basically ok. So, this particular kind of a mechanism has or now we can call this not just a beam, but it is a mechanism has this remote center for motion and we use two such beams on the on the two different sides of this glass plate and use that to really do the job ok. So, this is like a solid model for that kind of a design and then this is actually fabricated stuff ok, there are glass plates there is a cantilever beam which is fixed at some point and we now arrange this entire kind of a fixed plate and moving plate in such a way that the hinge is at the surface of the fixed plate ok. So, when I apply some force on this cantilever automatically this plate is going to move as if it has a hinge here ok, because it is supported now by this compliant mechanism here ok. So, of course, there may be some touch will be happening here it is not like this is not touching the fixed plate when the force is applied here there will be touch of this point happening to the fixed plate, but it will as you carry out this motion it will get lifted as if it is a it is a hinged at this point ok. And we have characterized this by under seeing under microscope how much is a is there any motion happening at this point or not all those things have been characterized to confirm that it indeed moves as if there is a hinge at this point although there is no physical hinge ok. So, this is how we have built one part of the mechanical system the mechanical plant so, to say ok. Then now we want to see ok, where are how do we place the actuators and other kind of a stuff in the system ok. So, we need to see now actuator and then the actuator needs to get guided in some kind of a straight line fashion and then so, that then we will be able to programmatically do the lifting process ok. So, you can see here that this lifting process is happening when this point is applied some force and this point like now is to move in some kind of a straight line fashion then how do we achieve that ok. We want just a motion below we in some kind of a vertical direction ok at this point as the plate moves there is some small you know because this is a circular arc this point is also going to go shift in the y direction also little bit ok. So, we need to have that some kind of a leeway for this point to move in y direction, but we are we are to apply the force you know in a vertical direction and for that we can use some straight line guide for this point to move ok. So, this is a straight line guide that is needed and again we want this straight line guide to have we can use some kind of a ball bearing for the straight line guide that also may work, but we are using under kind of a compliant mechanisms to reduce friction in the system and this compliant mechanism is based on this some kind of a spiral grooves in a small disc ok that kind of a compliant mechanism is what we are using here ok. That will avoid just a friction in the bearing ok, but I think there is no harm like no one can use directly some kind of a linear guide bearing and this job will be done no problem ok. In fact, we are doing that in the case of our other setups some other setups as well we are using some kind of a lead screw or ball screw kind of arrangement to get this kind of a precision motion. So, no problem. So, we are using compliant mechanisms as I said and then this this compliant mechanism will be operated by the voice coil actuator ok. So, one can have a ball screw and a linear motor kind of a combination not linear motion I mean motor the ball screw and a motor kind of a combination to give you a linear motion ok. So, the motor is rotating the ball screw and you get some kind of a linear motion at the output which can be used for to actuate this displayed in the angular fashion and you or maybe the linear fashion as well ok. So, this is how like we now think of like actuating the system and the sensors in the system can be our standard linear encoders where we can measure the linear displacement of the actuator and conclude about the angle of the lift because here now we do not have really a shaft on which we can mount the sensor here for the rotary motion measurement. So, we can measure the linear motion of the point which is getting actuated and conclude about the angular motion of the two plates ok. So, this is how now we put together all the parts in the mechatonic system. So, you have this compliant mechanisms you can you can see here ok. So, that is fabricated and it is in place for actuation then we are we are actually using also the force sensor to measure the force. So, this was the first time we are doing this process. So, we wanted to have entire characterization of this process to happen and for that you need this force measurement to be done ok. So, this force sensor of 6 axis force sensor load cell was used here between the plate and actuator ok. So, you have this actuator up here where this is a coil and then there is a magnet here and then this is a compliant bearing or flexure bearing which is used to just guide the block up and down ok. Now so, you can see the schematic up here now how do you take encoder input into So, we are using this controller as again a d space control system here you can use also like no other embedded systems like you can have a T-Y microcontroller to be used and is fine no problem ok. So, what we are using here is encoder to sense the position of this system then force sensor input is taken by analog to digital converter. So, this should be ADC here ok. So, this is a ADC analog to digital conversion is happening here and that data is in your microcontroller and then this is digital analog converter is used to give input to this amplifier which will actuate the actuator ok. So, it will flow some current in the coil and then it will actuate the coil ok. So, this is how like no this entire system can be having this closed loop. So, you can close the loop based on the encoder data or you can also based on the force sensor data you can close the loop. So, we want to say maintain a constant force that is possible with this closed loop system here. And then you of course, use this camera and zoom optics to kind of observe what is happening to the fluid and see all this details. So, this is how like we put together the entire mechatronics system as a lab setup kind of a scale ok. So, see again to tell you that if you want this to be like a product out then we replace this by using our microcontroller system with some small human machine interface to operate things ok. So, that is how like you know our mechatronics system will go as a product in this case ok. Now, let us discuss little bit about control what kind of a thing that you see if after seeing this system here what kind of thoughts you can gather for really exercising control over this system ok. So, we want to basically move this upper plate in very much control fashion to pull the pull the pull it down to execute our process ok. So, we want to say we want to maintain some fixed velocity as we pull it down ok. So, if this plate is pulled down we want to maintain a fixed velocity say say 5 micron per second or 10 micron per second kind of a velocity needs to be maintained ok. So, that we slowly kind of do this process and observe things and we should. So, this need not be slow as all the time, but we have some provision to change the speed and we say ok no I do not want to now do it at like no 50 micron per second kind of a speed. So, I have little faster process and then I observe. So, this is what is needed in the research to kind of change parameters and observe the things and then like you start studying the processes and conclude about like you know what is your observation and how the theory will match with your experimental findings and things like that ok that is how you carry out those processes. So, in this case now your plant is this mass attached to the compliant elements of this flexure bearing ok. So, these are so, you have a force sensor also is a part of your mass and then your plate and things also are part of the mass, but interestingly here. So, it is just a inertia that is there or there is something more to that. So, we are when we are operating by this actuator is just a inertia of these elements that is coming picture or there is something more to that. See of course, the liquid that is getting squeezed is going to apply some forces ok. So, do we know those forces those are kind of like no questions will come to mind to see ok that if I want to design control that control should be robust to these forces. Otherwise I design some control action ok and the gains are some chosen gains, but moment like you know the this liquid separation force starts coming in picture when I start separating then like you know this controller will start giving error it will not move the system anymore at 10 micron per second kind of a speed that I had decided to move ok. So, those kind of things are going to happen. So, this is going to be like a some kind of a disturbance rejection kind of a control you need to have because you do not know a priori what kind of a fluid force is going to come ok. It will change from fluid to fluid and from experiment to experiment also there might be some small changes that will be happening. So, that is where the feedback concept comes into picture very handy ok. See we have designed other point is like this we have designed the system such that there is no friction in the system ok. So, then control at flow velocities will be relatively easy ok. The fluid is giving some friction, but that fluid friction force is usually a as a viscous friction force ok. It is not a Coulomb friction kind of a force ok. So, that is why like you will not find a stick stick behavior offered because of the presence of the fluid ok. This and we are avoiding the stick slip behavior because of the two solid components are rubbing against each other that kind of a Coulomb friction we are avoiding by using the compliant mechanisms in the design. So, this is a kind of a way we can see that the concept of you know design in mechanical domain which will ease out some part in control or some part in the electronic domain has happened here ok. So, the way we did the same thing for the 3D printer case or you observe the similar kind of ideas in CD ROM drive ok. These are the kind of ideas that are to be employed to make sure that you know you are giving complete system solution not in mechanical domain separately and in the electronics domain separately ok. This is how we will think about you know in the as application of the concept that we are learned in this course in the practical interesting kind of a system example ok. And these ideas can be borrowed to many other systems that you say in your future activities wherever you are kind of going you will have an opportunity to work on such a systems and then you can give some elegant solutions to your problems ok. And of course, you can contact us any time if you are in need of such kind of solutions. Then this we see the now the some of the results of the control. So, control is done in a way that while squeezing we are squeezing from this point A to point B. So, this is a displacement or the plate position in M M kind of a displacement of the point of the end ok. So, we are not plotting the angle here we are plotting plotting the point of the motion of the actuator ok. Actuator moves the squeezing happens and like you know you will get this point here ok. This is displacement of the end point here ok. So, you squeeze it and then the squeezing happens with a constant force. So, we we have we have programmed the thing such that we squeeze at the constant force. So, that this squeezing happens we do not worry about the displacement at that point, but only while separating. So, then there is some delay for the fluid to get relaxed ok. So, we provide some delay for the fluid to get relaxed and at C point C the control is switched on ok. And this control is is simple PD kind of a control is there PDPID kind of control is there that that that is switched on to kind of get the lifting done here. So, the lifting is shown you know in the bottom side motion of the bottom or downward motion of the of the thing upward motion is squeezing and downward motion is is lifting or separation ok. So, so this is how we we we design the the plan for the experiment. So, if you see what is happening to the fluid droplet fluid droplet is is is between the plates it is not yet squeezed from A to B it will get squeezed and it will form a thing like you know film of the fluid and then from C to D the the separation happens and like you know you get this kind of a patterns that are produced on the surface ok. So, these patterns are what we are interested in to to study like how these patterns can be evolved with the control way and how these patterns can can give us some some some some application kind of a structure. So, so say for example, these structures if I like take and solidify ok they are liquid to begin with I solidify by some means and then if I solidify then they can be acting as a micro channels for studying like you know the microfluidic kind of a processes which are similar to what they are there in the biological systems ok. So, we can bio mimic the the the some of the devices or some of the organs that are there in the in the biological domain ok. So, this is a very interesting way of mimicking you know what is there in our you know nature many different systems are there those systems can be mimicked and they can be studied and after studying like we can make use of them in the application ok. So, let us see the say when this you carry out this process we will see now what happens to the force because we are recording the data on the force sensor we can look at that data. So, you see this this data is coming as a analog force sensor there. So, this data is little bit noisy this is I think this is after filtering further ok. So, we have used some kind of a moving average filter to filter out the data and remove the like some of the noise, but still like you know you can see some noise will be still there because the analog sensors are prone to pick up noise from the from many environmental you know places as we have seen. And we we need to employ some kind of filters to filter out that noise making sure that you know your data that you want to preserve or do you want to look at the data frequency and the filter frequencies are you know not messed up in in some way. The sense like you know your as we have seen in the in the in the previous lectures the the filtering is done at much higher frequency than what data we want to look at ok. See this this high frequency data is what is not what we want to look at what we want to look at is ok what is this low frequency stuff that is coming up as as we as we carry out this process ok. So, so that is where like you know you you filter out like you know this very high frequency data and it has been filtered out and it has gone down little bit and, but you you cannot have it completely 0 ok. Now, so, so, so when we when we start squeezing this this force starts increasing ok. So, this force increases up to point about 11 Newton force and then we we stop squeezing then the fluid relaxes and the force comes down to about 4 Newton ok. So, this is a delay part ok. And now, we start like you know giving a control to separate it out then force further drops and then it becomes to some some level here and then like you know we are carrying out the separation in this domain. At some point the force will also see you see that force may go little bit below 0 also ok. So, that is how you read this graph and like you know conclude about yeah ok what is happening in the fluids ok. So, about like you know maybe a half way through the process you will find this is force has gone down like you know force is below 0 you are actually pulling the liquid out or creating some kind of a vacuum inside the liquid or pressure that is lower than atmosphere inside the liquid ok. And overall like you know you can see that the lifting force is much smaller than the squeezing force that is a like you know very important conclusion that we got from this process. So, that when we want to scale the process up to kind of much larger kind of dimension we need to be worried about how do we squeeze because we our actuator design will will be based on you know this force ok. So, we are able to kind of squeeze more than like you know you want to squeeze more than or thinner kind of a film we need much kind of a higher actuation force there ok. So, these are these are different kind of a domain of you know analysis saying that ok in the fluids domain how much force will be required to squeeze a film to like you know thickness of say 20 micron or 30 micron or 50 micron or 100 micron. So, like we go lower in the thickness our force will start more and more ok. So, this is kind of like obvious, but we what is not obvious is like you know how this force scales ok how much force more I will need to apply what is the quantitative aspect of this that is aware different domain of you know fluid dynamics working. So, here you can see now this video for angular lifting ok. So, you can see before playing video I will show you this is a point where the force is applied ok. So, when you squeeze like know the plate is squeezed here and then there is no contact between this some small gap is maintained there and as you start separating this gap will be absorbed first and then this plate. So, you can see this is acrylic plate up here this is our mechanism which is having a fixed point here and that fixed point there this kind of a mechanism design is such that it creates a hinge point at the end of this plate here ok. So, you can see that kind of a lifting happening. So, part of the lifting you may not be able to see the complete plate because only the lower part of this plate is getting seen here there will be some part which is hidden behind this ring ok. So, let us observe that you can see as a squeezing starts like this gap will be as a separation starts this gap will be absorbed and then now this is lifting ok. So, this has lifted completely here ok. So, this we do not want much angle to lift here we want just a small angle so that this film gets separated. So, 2, 3 mm kind of a motion is sufficient here ok. So, this is how this setup is now working ok. Then what we can do about that we will see in a minute ok. So, this is another kind of a mechatonic system which is a parallel lifting kind of a system ok. So, we will not get into too much detail about that only thing here now the actuator is different ok. Instead of the voice coil actuator now we are using a translation stage ok. So, here we are using this stepper motor based translation stage from the hallmark thing that we discussed in the class at depth. So, this stage is giving us a possibility. So, this motor is a stepper motor which is having a torque which is much higher than the friction that is there in the system. So, we have seen that for with the micro stepping kind of a driver that is used for the stepper motor we are able to kind of like move this plate parallel to the other plate in a very smooth fashion here ok which is acceptable for our experiments that is what I would I can say. It will still have a stepping kind of a effect very small steps there will be some micron or submicron kind of a steps will be there, but that is not really bothersome for our experimental observations to really you know get to. So, that is why I said like you know we can have actuator both as that voice coil actuator also possibility or we can use this stepper motor kind of actuators also. So, here there are these ball bearings to kind of guide this in a vertical direction down and stepper motor to actuate. So, lot of friction is existing in the system, but that is getting overcome by the stepping stepper torque and even them we are able to move in a small steps at a very slow speed. So, this action will happen now as a small steps ok. So, this is not really kind of a continuous smooth kind of a motion, but it is going to be in the steppy kind of a fashion, but in since these steps are very very low in size we do not have any problem in really executing this setup. Now, what we have done with these setups? So, both are both of these setups are like put developed in house for as a mechatronic system and what we can do with the setups is what I will talk about little bit now. So, to give you some kind of a sense of what you know interesting the ideas or you know fabrication this setups can do. So, this is where like we introduce this you see this video here the this is now top camera recording this thing where the squeezing happened just now ok. The squeezing of the film has happened here already and there are these small little trenches that we have you know machined on the surface of this plate one of the plates and then you can see that now the fluid the air starts penetrating through those trenches professionally ok. With this air penetrating that they through them they are designed to kind of do with some kind of a dimensions. So, that like you know there is this air doesn't progress too large in this plane, but it in this kind of a air finger progresses much larger distance or and this progresses much larger distance this progresses even larger distance than that like that we have designed these trenches to be ok. So, with this we are able to now produce like you know the control structures where you have one branch splitting into two branches only and then further splitting into two branches only further splitting into two branches only. But at the other place where we didn't have this this anisotropy on the cell plates this is a random process is happening still ok. So, this is how we exercise additional control ok. So, the control that we had so far was only the speed of the of the plate to promotion ok. Now, we have these additional controls that are coming up by by virtue of some kind of anisotropy is on the cell plates ok. So, in the form of these pits or holes or some. So, these plates are no more planar plates these are like having some holes and now we are using acrylic plates. So, that you know we are able to see through the plate to see what is happening to my fluid and also we are able to machine these acrylic very easily. I will show you like know how this entire process goes in a minute ok. So, now, let us see this kind of a topology is coming up on the. So, this is one can see that this this can be scaled further and do lot of different things with this. Now, we have this picture which shows that ok we have this you know by studying this process phenomena in much more detail in the in the fluid dynamics kind of a domain which we are not interested at now because we are like now looking at mainly mechatronics perspective, but we are able to fabricate then like know these multiple generations of the split ok. So, this is like know first split split here, second split here, third split here, fourth split here and fifth split here. So, like five generations we are generating these practical geometry structures and this process can be useful for as I said like you know some biological kind of applications ok. Now, this is under alternate control under control that we are exercising by putting them holes now instead of just at those kind of scratches or some kind of pits. Now, these are holes completely through and through holes and they are allowing the fluid the air fingers to grow ok. So, how do we kind of make them grow more or less like know there are lot of some kind of a study has been done about that and all these kind of things are arranged in a way that you know this kind of a complete symmetry of the structures can be possible to be produced ok. So, again the process exactly is the same like in the mechatronics kind of a perspective we are still squeezing the fluid and then separating it out ok that is it ok, but now it they are they are able to produce with that process a very interesting kind of a structures and these structures can go with the array kind of a pattern they can go as a as a full like you know triangular array of fluid and then further like the hexagonal array or some other kind of a possibilities that can be there and this can be done now like know on much larger scale as long as like know we are able to manage that a big size scale see big size plate motions this can be done at a much higher kind of a scale ok. So, the scalability is there inherent because it is just a fluid that is going to be working there in all places. So, we have worked out some kind of a non-dimensional numbers under which these processes will happen very easily and and think like that in the in the fluid domain what are the non-dimensional numbers governing there. So, if you have in case you are using your own fluid you know what is what are the properties to look for and and think like that all those details can be found in this in this paper ok. And then these are like know multiple kind of versions of the structures different patterns and then you have this with the multiple holes now instead of just holes on the periphery we are using now holes everywhere and then what are the pressure curves that this is a cross section of the or this is like a showing the pressure that is built up in the inside this film like like a parabolic kind of a passion, but when we have this multiple holes then like the pressure built up does not happen so much ok. And many places you will have this wherever these holes are you have atmospheric pressure there which is like you know horizontal line here ok. So, these pressure gradients as we saw already in the previous video you know this is also working now for giving you this you know different kinds of patterns ok. You can see here this triangular shape patterns and we will show some other patterns also ok. So, let us see these are the other patterns that can be produced ok. You can get square patterns, you can get hexagonal patterns and you can mimic the lift completely the lift vanes we took this image and by processing image we found out what are the anisotropies that are to be there on our cell plates and we can produce that also reproduce that also ok. So, here is a thing this image is missing here, but that image was showing actually the reproduced part of these vanes ok. So, then the total summary of this process is somewhat captured here ok. You can see this video now ok. So, this starts with this one setup here that we just saw in the previous slides also and the process starts with this modifying the cell plate. So, you can see this is a cell plate here and it is like you know we have this home developed micro drilling kind of a system here ok. So, we have used this motors for this from the aero modeling you know the propeller motors and one can have very high speed for those motors and we can design this kind of a you know again mechatronic system of drilling holes micro holes which is done in house ok. So, now, we have put a fluid droplet here which you see this upside down droplet up here ok and we will start squeezing the droplet by giving now the rotation to the to the ball screw ok. And in this fluid film is now droplet has touched and then fluid film is getting squeezed ok. This fluid film gets stretched and then it touches this holes as we saw and then we do it at high speed we will not get the geometry that we want ok. We do so we do it as a slow speeds or the speed that we have calculated a prairie and then this geometry starts coming up in the thing ok. So, this is how you see that. Now, you can see many different kind of geometries that are fabricated by this control ok and this is a different setup. So, you can see these are flexure bearing up here ok. So, maybe we can go back a little bit and then see this spiral flexure bearing ok. So, let me pause here ok. You can see that these are spiral grooves here for the bearing ok. The spiral grooves in the plate can allow this up and down motion happening ok and such such kind of a bearing is there at one end and at the other end and these two ends you will constrain it to move only in the straight line up and down ok. So, this is how the the angular lifting setup that we have mechanics we have seen and then this is a experiment with that ok. So, maybe we just yeah I think we have seen. So, this is see this is if you do not have any anisotropy ok or you do not have any control this is how the very slow the process is moving very very slow at whatever 5 micron time micron per second speed. You see these fingers evolving in real time right now actually and then they evolve and like you know then they they form some patterns on the surface ok. This is without control and then we have with control we have this ordered kind of structures here ok and then different patterns coming up here ok. So, this is what we have seen already some part ok. So, maybe I think we can skip the rest of the part ok. You have these different interesting patterns that can be fabricated and one can explore this more I mean you know with different kinds of grades you can have different possibilities. Say for example, if you use evaporating kind of a liquid ok evaporating solvent is evaporating then you get this kind of a patterns ok. So, this is a combination of liquid drying on the surface versus and this LHO process ok. So, this this kind of patterns are very easy to get in this process and then we can inverse invert this by casting in in the material called PDMS this is a kind of rubber kind of a material in which this can be casted and then this this can act as a as a microchannels ok. So, these things will act as a microchannels of different cross sections. So, we have one of the applications with one of the collaborators Prasabhijit Muchumdar from Chemical Engineering in IIT Bombay. We are developing a platform for drug screening or chemo taxis ok. So, we will not get into the details of this application, but the point is to say that this is kind of a research will lead to some kind of applications eventually ok. These are other applications where we have we have a leaf mimicking micro pump ok that has been developed here ok. So, so there are many many different application possibilities and collaborative possibilities for such such a kind of a work and we can explore those in the in the future in more detail ok. So, say for example, there are there are this condensation over this fractal geometry or heat exchangers with this kind of geometry. There are some of the kind of sensors with this or energy application solar electrodes or or here even the electrodes for water splitting to get get hydrogen generation or hydrogen production done like lot of different kind of possibilities that exist and some of them we are exploring in our our lab and and you feel free to explore what you want to you know and then feel free to talk to us if at all you want to you know have some some application to be to be done ok. So, this is like you know the team that has worked behind this and must acknowledge like imprint grant which was which funded this project and these these are my collaborators faculty for this particular part. Prasamita Bhattacharya we are collaborating for the theoretical kind of aspect and Professor Abhijit Mujumdar from Chemical Engineering for Bioapplications in this domain and these are of course is a big team of the students and and research RAs and PhDs students who are working behind although I am getting an opportunity to present this work to you ok. And then there are industry collaborators like Dr. Dhananjaya and Mainan from from Strategy Automation and Dhananjaya from Ashira Labs ok. So, with some bio applications future development we are doing with them ok. So, thank you very much and I am hoping this course will give you a good lead in developing your own kind of mechanical systems in whatever application area that you are you are developing. Thank you very much. Bye bye.