Hi, and welcome to another video on flashing a free operating system on your mobile phone. In this video we are going to flash a Samsung Galaxy S4 with Linux OS. Linux OS is an Android distribution that supports a large number of devices and is one of the most popular custom operating systems for Android devices out there. To find out more about the motivation behind this video and about our campaign, you can go on the campaign website OpscyclingAndroid.com. So the first thing we have to do is click on Get Linux OS. We have brought to the devices overview page. And then go to our device model, in our case we have Samsung Galaxy S4. And the model number is IGT-I9505. So we click on the device, we brought to the devices info page. And the first thing we are going to do is to download the factory images. So this is done by clicking on Get the builds here. And then downloading both the factory image, which you see I've already downloaded to speed up the process and downloading the recovery image, which I've also downloaded. And what we can do additionally is to download the checksum files. So this you would want it to save and just prepend something like SHA256, I mean I prepend something and then click on Save. And you see I've already done this as well, just say replace but these are very fast downloads because it's a small file. So once we've done this we go to installation and a warning box tells us to follow these installation instructions step by step precisely. And okay so going through the basic requirements we need one to read through the instructions at least once. Then secondly make sure that our computer has ADB and fast boot installed, so the Android SDK to actually communicate, be able to communicate with our computer. And then third, enable USB debugging on the device and then make sure that this is actually the right model that we want to install a custom operating system on. And to check that we can actually use the phone in its stock operating system and everything works. And sometimes you should download the latest factory image from Samsung in this case to also make sure that you have the latest firmware installed. And then sixth, if anything breaks then sure as it's not responsible. Now we can click on show instructions and the first thing we notice is that actually these installation instructions only work for Windows PCs and I'm not a new Windows PC, I'm using a Linux PC here. So since I can't follow through and download ODIN which is a Windows program that allows to communicate with the device while it's in download mode, which is kind of a similar thing to fast boot mode on Google Pixel devices, I'm going to find a page that shows the installation instructions for Linux PCs as well. So we need to go back to the linuxOS.org homepage, click on get linuxOS again, show discontinued the devices and go to the Samsung topic and then scroll down a bit and we're looking for a phone that is similar to ours and has a different installation instructions page and I just happen to know that GT-I9506 doesn't use ODIN to flash the operating system and clicking on installation and show instructions, we see that instead of ODIN, in this case Heimdall is used to communicate with the device from the computer and Heimdall is a cross-platform and open source tool for interfacing with the download mode on Samsung devices and it's available on Linux. As you can see I've changed the window configuration, so now we have on the right hand side a webcam feed showing the device, the Samsung Galaxy S4 and on the left hand side still the installation instructions open. So we're going through the basic requirements quickly again, we should really make sure that we have ADB installed and I already set that up on my computer, if you haven't done so then you can follow instructions by clicking on the here word and the third point is to enable USB debugging on your device, I will quickly show that to you. So from the lock screen we unlock the device and we go to settings and on more we scroll down to about device and then at the build number we click as many times as we need or we touch it as many times as we need to become a developer and now the developer options menu is unlocked which when we click on we see after debugging USB debugging which we will enable by pressing OK. Now that we've got the basic requirements out of the way we'll go to preparing for installation which in the first step requires us to install the Heimdall suit. Since I'm on Linux I follow these instructions and after downloading the Heimdall suit to install it and we can verify that Heimdall is indeed installed by running Heimdall version in the terminal Heimdall version which shows we have Heimdall 1.4.2 installed. In the second step we're going to power off the device and boot it into download mode so powering off the device just by holding the power button and power off and now with the device powered off we hold the volume down, the home and the power button. So we are shown a different screen which reads volume up, continue, volume down, cancel. So we'll proceed with volume up and now we've successfully booted the phone into the download mode and the third step we can skip since it's only for Windows users and in the fourth step we make sure that Heimdall is indeed being able to communicate with the phone by connecting a USB cable to it and the computer. Now that we've connected the USB cable we go on the terminal and type in the command Heimdall print pit. So this is outputting some information about the partitions on the device and what images are installed on them and then rebooting the device. So indeed the device rebooted and we can say that Heimdall is installed and working properly. Now that the device rebooted into the system we can proceed with the section on installing a custom recovery using Heimdall. In the first step we download the custom recovery image, in this case not TWRP but the nearest OS's own recovery image. Since we've already done that we just have one additional step to do and it is to actually verify that we've downloaded the tracked file using the checksum image file. So image.char256 and it spits out okay so we can be sure that we don't have a corrupted image file. In the second step we're going to power off the device and boot it into download mode. You've always seen this before so just unplug the USB cable before and then pressing the power button power off confirming and now that it's powered off we press the volume down home and power button together simultaneously and we see this familiar screen. Press the volume up button to boot the phone into download mode and insert the USB cable into the device again. I'm now issuing this Heimdall flash command which I'll copy over to the command line and we still have to change the image, the recovery file name and this should be the correct file name and pressing enter to issue the command and on the device we see a blue transfer bar appearing and now it's full. Going back to the installation instructions it tells us that indeed this blue transfer bar shows us the recovery image being flashed and now that it's full it's fully flashed and what we're going to do next is unplug the USB cable from the device and then manually reboot the device into recovery and on this phone we have a removable battery so we're going to remove the case and take the battery out. Now as I told you before these are not the device instructions for the actual model I have here and indeed they differ in how they can be booted into recovery mode so if you go to the actual device installation instructions page we see that with the device powered off we need to hold the home volume up and power button and then let go of the power button immediately when the phone vibrates but keep holding the other two keys and this is different from the installation instructions we have been looking at the whole time so putting the battery back in we hold the volume up the home and the power button and as soon as the phone vibrates we let go of the power button so this brought us to the recovery image to the recovery system and we have a few options here so going back to the other installation instructions page we will install lanyardOS from recovery so we've already downloaded the lanyardOS installation package just need to verify that we actually downloaded the correct file so the chart 256 some command again and this time we verify the factory image file which tells us okay so we've actually downloaded the correct file and it's not corrupted and second step basically tells us if we're not in recovery we should reboot it into recovery but we already in the recovery mode and next we're going to factory reset the phone and format data format data slash factory reset so this is again different from the installation instructions page we're looking at but on the previous on the actual one we see that yeah we should tap factory reset a menu option and then select format data slash factory reset and now we can side load the lanyardOS zip package by going back to the main menu and then selecting apply updates and then apply from adb and now we can plug the usb cable back into the device and now on the computer in the terminal we side load the factory image so adb side load okay this should be doing the trick and now in the terminal you see the progress and this is going to take a while to actually side load this image this the zip package now that the flashing processes has completed we put back into the recovery interface and going back to the installation instructions the sixth the sixth step is optional namely flashing some some add-ons we don't we don't flash any add-ons here and since everything is installed correctly we click on the arrow back button and select reboot system now which can take quite some time as you see in the box the first boot usually takes longer than 15 minutes depending on the device okay so there you have it we unplug the usb cable we should also not forget to she put the case back on and we agreed it with the hos creator which will help us set up the device i hope you enjoyed this video and see you next time


Go outside. When you're in mob 2, go outside with all your stuff to get a small portion. Your ADs are optional. Oh, yeah. Now we are. Oh, yeah. I'm going for her. It's back here for her.  You know how the symptoms are. Strap it. Adjust it. Tie it off properly. Most comfortable strap your force makes. Gas mask on the left-hand side. Flip it as you assemble. Put it together. And show me real quick. Daddy, I think it's a bit. It's awesome. Oh, that's in there? Yeah. All right. Go grab those. I haven't put it on. All right, you can put that on. Did you go?  Just assemble your weapons. Just assemble them to the... Line it up. There's your counter up here. First, name a pool to the rear and a room to the rear. Make an order. Click. Select to burst. Where are you going to apply it? Let's just say it's right here. On it. This is your piece. The H over the affected limb. You're going to go around? Yeah. I can make fun of these guys. Hopefully...


Okay, let us continue what we were doing in the last class. We were looking at rolling tires, we were looking at what we called as free rolling and we were also, that is what you are doing, free rolling and we were going in deep into the concept of how contact pressure influences various things that are happening at the contact patch. So, small slip of tongue in the last class, please note that when I drew the tire, I think that is how we drew the tire and that is the velocity. So, whether it is breaking or accelerating, the velocity, the direction is the same. So, I think that instead of acceleration being in this direction, I put velocity, please note that that is acceleration. So, the acceleration is in that direction. So, the ground we said will be, you can have that stationary and the ground moving in the opposite direction. We said that that is the relative velocity. So, please note that it is the acceleration. It is obvious, but now the less I just wanted to make it clear as to what we were talking about. There were some questions on tires like how tires are built and so on. That is a vast topic. In fact, tire mechanics can be a course. Unfortunately, there is only a part of this course. So, we will not be able to go into the details of tire mechanics completely. We will only talk about tire mechanics from the perspective of vehicle dynamics, how the tires interaction is going to affect the vehicle performance. That is what we are going to talk about. We are not going to talk about tire design and so on. That is a topic by itself. But now the less it is important that we talk about how or what is the construction of the tire and courtesy JK tires. I am giving you the slide, which talks about how tires can be classified. So, tires are classified based on construction into what we call as a radial tire or a bias tire. Today, radial tires have become extremely popular and all passenger car tires are radial tires. In this country, in India about 20, 25, 20, 25 percent of the tires in the truck or radial, but elsewhere in, for example, North America 90 to 95 percent of the tires in the truck or the bus segment or radial tires. Still, there are bias tires running in India, but in most of the developed countries, the tires are radial. There are a lot of advantages of radial tires. The foremost amongst them being the fuel efficiency. Radial data shows that the fuel efficiency or the difference in fuel consumption can be as I as 5 percent. So, radial tires are extremely popular in the truck market now and it is becoming popular rather in the truck market. The other tire is what is called as a bias tire. Let us understand what these radial tires mean. This is a cut section of a radial tire. So, you can see here that there are, look at that there are steel, what are called as steel belts and this is what is called as a ply. Let us get a cut section so that you understand this much more clearly. That is a truck radial tire. Look at that. It is extremely complex. It is complex from two points of view. One is that it has a number of materials and several reinforcements that make it stable, that make it efficient, that make it last longer, gives you a good ride and as far as possible reduces the fuel efficiency or reduces the fuel consumption and increases the fuel efficiency. Again, courtesy of J Guitars, we will look at what are the sections, I mean look at the different components in the sections and what the section is made up of. You would see that there is what is called as a body ply. You can see that the body ply which consists of a number of wires, a number of wires. So, they run like that from one bead to the other. So, you would see that it keeps running like this. So, they are radial in nature. That is why it is called radial tire. So, the body ply has steel reinforcement in a truck tire. We are talking about truck tire here. So, that is the body ply. Here you can see it may be here more carefully. You can see that that is the that is the reinforcement in the body ply and you see that the body ply. The body ply has rubber on either sides. The most important there are number of them. I am not going to explain each one of them. The most important which is towards the inner side is called as the inner liner. So, in other words it is inside. If this is the body ply and then what is inside this is what is called as the inner liner. And outside this, you can see that predominantly that is what is called as the side wall. In other words, the question is what is side wall. So, this is the side wall of the tire. So, in between the two, there are some components. Let us not worry about it. So, there is a reinforcement for us as far as we are concerned. There is a reinforcement steel reinforcement which is rather protected on either side by rubber and this side this is what is called as the side wall. This region of the tire is what you call as the buttress of the tire. Now, you can see that the steel reinforcements go all the way and then wraps around what is called as the bead or the bead core. You can see that here there is a bead and then the reinforcement, the steel reinforcement wraps around and comes out in the other direction. So, you can see that here very clearly that it goes like that and then comes around and then wraps around the bead. Now, around that portion of bead is solid, heavy. This is a very important guy. Last time we saw that he is the guy who is going to interact with the rim in order that the loads are properly transferred and so on. So, that portion is made up of a number of reinforcements. There is what is called as a steel chipper wrap around to protect the bead and then you have a chaffer and so on. The chaffer and chipper all of them help the bead to actually interact with the rim. So, there are other things there. Let us not worry about it. So, the first thing is that this body ply, important component, either side of it as rubber, side wall and inner liner wraps around the bead. Then when you come to the top, you have what are called as bells. These are what are called as the steel belts. You can see it here. They are in this case this is all steel radial. So, this is this ply is steel as well as these belts are made up of steel. They are steel belts. They give the stability for the tread and you can see that this is not only one belt, there are a number of belts. There is what is called as a transition belt and there are two working belts and then there is a protective belt. So, these belts have steel wires running. Say for example, if you look at it from the top, so you have wires running like that in one of the belts and then running like that in another belts and so on. So, the two belts working belt one and two are very important belts and as I said that gives that stiffness, the lateral stiffness and the longitudinal stiffness to the tread. The construction there is very complex. We will leave it for a minute because we are only looking at the mechanics of the tire and not into the mechanics of load carrying and stresses and so on into the tire. So, we are not going to look at the design. From design point of view, how you place that belt, what is the width of the belt, what is the angle and all these things, how many belts are used, all these things become important. There can be four belts, there can be three belts and so on. Then on top of it, there are some layers again of rubber and then ultimately you have the tread about which we were talking about. So, these are the, this is the tread. We will see that in a three dimensional picture and this is the tread. Tread is the one which is in contact with the ground and the mechanics has lot to do with the tread as well as the belt and how that interacts with the road. That becomes very important and that is what we have been talking about and we will continue to talk about that in this class. What is tread made up of this rubber?  We will see, I am not going to the details of what is this composition, how it works and so on. This can be natural rubber, natural rubber, N R plus, natural rubber is usually called as N R, butadiene rubber, B R, sterine butadiene rubber which is S B R and so on. So, it is a combination of all these materials. So, we will not go into the details of these materials. Nevertheless, to say that, that is the passenger car, we will come to that in a minute. So, you can see that the passenger car tire for example, as well as the truck tire is made up of a number of different compounds of elastomers. In other words, different regions of the tires have different compounds of rubber. So, it is not one rubber. Rubber or elastomer is a very generic term. It is not that there is only one compound that covers the complete tire. In other words, tire is just not made up of only one compound, the number of compounds. As I said, that is not the intention in this course now. That is the passenger car tire. Essentially, the construction is similar but not exactly the same. The body plies are not necessarily made up of the same steel but it can be of different materials. Then, as I said, we will look at the biased truck tire. Unlike the radial tire where you had one body plier and then you had belts, here you have what are called as plies which run throughout. One, two, three plies as you can see which runs throughout and are arranged in a position, arranged in such a fashion as you can see that they are crossing each other and that gives the strength for the tire. Because of the way these are arranged, there is a performance difference between the bias and the radial tire but since the bias tire is almost given way to radial tires, we are not going to talk much about. There is no point in now comparing bias tire and radial tires. So, we will concentrate on radial tires and how that works. I just wanted to say that there is also what is called as a bias tire. Bias tires are still used in trucks. Now that is a typical passenger car tire. You can see the treads there. The treads are very clearly seen. There are various ways in which treads are designed. You can see that there are grooves there, there are grooves in the tread. These grooves, this is a passenger car tire and these grooves are there in order to carry water or minute sand as you go over say a sheet of water. In other words, they are channels for the water to escape as you go under wet conditions. The tires are basically classified into what are called as rip tires. This is a truck rip tire. You can see that there are rips. There are four rips in this tire and lug tires. These are what are called lug tires. The rip tires are usually used in the front wheel, not necessarily that it should only be used in the front because there are buses which uses this in the rear also. Basically, this is a steer axle tire. It performs very well when it is in the steer axle. So, this is a rip tire which is used in the steer axle and that is a lug tire which is usually used in the drive axle. That is the rear. So, these are rear tires and the front is a rip tire. But in a passenger car, you cannot have two different types of tires. So, you have tires which are a combination or a hybrid of these two which would say all wheel tires. So, all wheel tires are a combination of this kind of lug pattern and a rip pattern. So, you would see that a passenger car tire is sort of a combination of these two. Even for truck, you have a combination all wheel tires where you can use which you can use the front as well as in the rear. So, this is sort of a very brief introduction on how the tires look like. Though we are not going to use that knowledge in this course, we are going to go more into how the tires interact. But nevertheless, I think it is good to know how the tires look like and so on. Now, coming back to our contact patch, coming back to our longitudinal forces and all that what we did in the last class, remember that we were looking at a tire which is under free rolling condition. Let us get back to what we were doing in the last class. We will switch and go back and look at some practical aspects of this contact patch as we go along. So, that was the tire which was rolling. We talked about the varying radiuses in this tire. We talked about R0 becoming RE and then becoming RH and so on. And under this we had drawn three figures. We talked about the contact patch. We just given a two-dimensional representation of the contact patch and let us now look at three-dimensional representation of this contact patch. Two-dimensional sense that it just cut at the center and looked at it. It is very theoretical, but let us look at it from a very practical point of view actually how the contact patch looks like. So, this is a finite element model. Again courtesy jacket as we have a contact patch, finite element model of a contact patch. Different colors here indicate the magnitude, red being the contact pressures are higher and blue being the lowest. So, in other words, you see that the contact patch is not uniform and as you go to say for example, a truck ruptire the contact patch is absolutely not uniform. Though we assumed that a shape in order to understand the fundamental interactions, the contact patch is not uniform. Let us understand a bit about contact patch because that is an important parameter for the vehicle-road interactions. If this tire is to be made up of a membrane whose bending stiffnesses are very low, say for example, you take a balloon, blow it and then just press it on the ground. The contact pressure will be uniform. Contact pressure has to be just equilibrate this, the inflation pressure and so the contact pressure will be uniform. Strict conditions that has to be the case or theoretically that has to be the case when there is no bending stiffnesses and other things that we are going to talk about are involved. Unfortunately, a tire has a lot more things than a balloon. The first thing is that the tire is not straight like that. It has, you can see that it has say grooves. That is what you see here that it has this kind of grooves. Contact pressure is actually, let us look at that. Let us say that that is the inside. I am just extrapolating or I mean exaggerating or blowing or zooming the area at the center. Now, here is the inflation pressure that is acting and here is the road surface. That is the road surface. In other words, there are grooves. The grooves become quite complex if you really look at that kind of tires. The grooves become complex and here again you have grooves. If you now, again we will do a thought experiment, if you go and sit here, this part is not supported. That is not supported. Because of which there is going to be a local bending, so there will be, this part of it will now start bending because it does not have a support. There is an inflation pressure that is acting that is going to sag. That is going to get deflected. In other words, there are lot of local deflection. Number one, when compared to a nice membrane or a balloon which you keep it at the surface, there are going to be local deflections. Yes, we are now, right now we are not talking about water or anything entering there. We are just acid rolls. This is exactly how it looks like in that picture, acid rolls. So, we are not, in other words, we are not looking at a soil road, I mean tire in a deformable soil. We are looking at tire which is running on asphalt road which does not deform. For all practical purposes, that is fine. If the soil, then the whole analysis is very different. How it, how the soil deforms, all those things have to be taken into account. That is why you have what is called off the road tires which is called as OTR or off the road tires. We are talking about truck tires which are running on asphalt or flat roads. So, the first thing is that the constant pressure is affected by these kind of local bending, right. So, the pressures in this region on either side in these regions, they are going to be affected. That is going to be affected. That is the first thing, right. So, that is one factor. The other is the side wall. So, that is the side wall. So, actually what happens is this. So, under, look at that. You know under pressure, the side wall will be like this. So, there is a deformation of the side wall and the shape of the side wall is different from what it, what it is now and when it is under pressure, then the side wall shape changes, right. And that is going to have an effect which is very important for this contact pressure distribution. In other words, you will see that if this is the undeformed side wall, then under load, this becomes the deformed side wall. So, under these conditions there are a number of forces that act on to this tire. There is going to be some tension or in other words, a membrane force that acts there and there is going to be an inflation pressure force that is going to act at that point. So, there is going to be a membrane, there is going to be an inflation pressure and there is going to be a, of course, the ground reaction and so on. So, because of this effect, if I call this as TX, because of this effect, we have a bending. This is actually, you can imagine that, first let us look at it physically, then we will look at the T equation. It has a tendency, so there will be actually, there will be, this will be the inflation pressures that will be acting and so there will be a force which will be acting in that direction. The sum of this inflation pressure forces, it may be not here, may be somewhere you can say here acting and so on. So, because of this, there is a bending because of these forces, these forces, these forces and all that, there is a bending that is bending moment that is created. The bending moment is the sum and substance of all the forces that are acting, one in the positive direction, the other in the negative direction and so on. So, that bending moment, what we will look at that bending moment closely now. So, that bending moment, let us get into this and let us just expand that. So, that is, that is the side wall. Now, assume that this whole thing is now bent and so we have a bending moment acting at this place as you had seen there. So, now what would happen because of that bending moment, there will be more reaction forces here, there will be a reaction force here, depending upon who wins, there are number of forces there, who wins, there will be a reaction force at this edge. In other words, this bending is going to alter the contact pressure distribution, this bending is going to alter the contact pressure distribution. Suppose the bending wins over or one of the forces here wins over and the bending is like this, what would happen to the contact pressure in this region? The contact pressure would increase. The contact pressure here would increase. So, in other words, the side wall geometry and configuration would result in a bending moment at the ends because of which the pressure here, the bending moment here will be compensated by the, that will be the reaction. This is the action and the reaction and because of which there will be contact pressure will be here or higher contact pressure would result at the edges. So, that is what you see here in this figure at the two edges, you would see that the contact pressures are higher. It is not necessary that it would be like this, it depends upon a number of forces that are acting. Number one is that there is what is called as the, the membrane force, this which we had drawn there as T. The membrane force depends upon two things. One is that there depends upon the radius of curvature. Please understand that there are two radiuses of curvature. One for example, here is a radius of curvature. The radius of curvature here is going to change and then there is a radius of curvature in the other direction. So, there are two radiuses of curvature in the tire and so, both the radiuses of curvature have an effect on this Tx. Both the radiuses of curvature have an effect on Tx. Of course, the other things that have an effect on Tx, on Tx are the inflation pressure and the force in the Ty direction. We will not go into the details of this equation. I just want to say that there is a force in the side wall which you could loosely call as a membrane force which acts in the side wall which has an effect of course, on the bending of at the contact patch edge. That is the first thing. The only thing I want to point out is that this force is affected by the shape of the or the profile of the side wall as well as the inflation pressure to which you subject the tire. These are the two things. When I say geometry, it is Rx and Ry are included. That is the first thing. The other things that affect the moment are the inflation pressures. The inflation pressures, there are two ways in which it acts. You can resolve it in two directions, vertical and the horizontal direction. That is what you see there, the inflation pressures acting in the horizontal and the vertical direction. They have a tendency to have a bending moment in this direction, one direction and this Tx has a tendency to have a bending moment in the opposite direction with the result that there is an addition and there is a subtraction. In other words, it is very simple to understand. If this is the W, what is that W? Let us get back. Say this is the W, this distance is the W. Hence, you will see that everything here depends upon the geometry. If that is the W, then you can see that there is a minus sign here which acts in one direction and then the other things is in the opposite direction due to inflation pressures in opposite direction and acts like this. Ultimately, what is this moment, bending moment that decides the variation or the difference in pressure? Just to summarize, just to summarize what it simply means is that the inflation pressure, the inflation pressure that is acting would have been the same as that of the contact pressure, but for the presence of local bending which we saw here as well as a global bending, I would call it as we had seen here. Because of this bending and of course because of the membrane forces and so on, the contact pressure is not the same as that of the inflation pressure. That is the first important point. Now, there are number of design parameters which affect the contact pressure. Let us agree that they are not, it is not the same. Actually, we were looking at the rolling tire and right now our explanations are more to do with the stationary tire. Rolling tire has other factors which are very interesting. Before we go to the rolling tire, say free rolling tire, then we will go to a tire which is breaking, how the contact pressure changes or accelerating. And lastly, the most difficult of these cases, what happens when the vehicle takes a turn or cornering. So, in this class, in today's class, we will concentrate only on rolling tire, free rolling tire and we will just get into what we call as breaking or traction. Next class, we will expand that and so on. Clear? Any questions? In the y direction, right? In the y direction. Yes, in the y direction. x and y, x I had given here, y is in the other direction. F y is in the other direction. P i is the inflation pressure. P i is the inflation pressure. Let me write down, if you have doubts, let me write down. T x and T y are already explained. T x is the side wall tension in x direction and T y is the side wall tension in the y direction. P i is the inflation pressure. Yes, one minute. Inflation pressure. This is the free body diagram from which we are determining the... What I have done is essentially, I have cut this and then put the equivalent forces here. Yes, see what we are... Good question. Actually, in most of these analysis, we have left out centrifugal force, so as it rotates. In some of these conditions, if you look at literature, centrifugal force becomes important, but under many conditions, we neglect the centrifugal force because of rotation. You have to be careful. Usually, in a truck tire, we are looking at the truck tire. The centrifugal forces are not that very important because of the speeds, but in a passenger car tires, centrifugal forces become important. Right now, we are not considering that, but then there will be another force, other forces and there will be some changes here and so on. This is only to explain more physically the bending, what happens. I am not going to rely on these equations. Today, most of us do not rely on analytical expressions. We go to finite elements. All these things, all the results that you get, all the niceties are beautifully brought out in finite element analysis. But, nevertheless, this becomes important in order to understand what really happens or why the results are what you see in finite element. That is the reason why we explain what is bending, how does it bend, what are the forces which cause bending. We cannot do hand waving. That is the reason why we write down these equations and see, look, there is a moment and the moment consists of... The moment is due to various forces and forces act because of inflation pressure, because of the force of the membrane or the side wall forces. These participate in this moment and so on. All these effects are accurately brought out by the finite element analysis and hence we look at the results ultimately in the finite element, you know, contact pressure distribution. Clear? In which case, you can also add the centrifugal force and so on. So, we will look at now rolling time. There are other things that become important. Why coming in x direction? This is the way actually the... This is a membrane theory. We are not going into the equations. So, we would write now not going to the derivations of these equations y r y r x r x r y and all that. We will not... Because then the topic becomes very difficult and so this is not F. This is not F. This is F v. I thought you have to ask me r y v. This is F v and F v is this force that is acting here in this direction. The force which is acting at the center here and that is F v. That is not F y that is F v. But r x and r y come into picture and that is F v. Actually, it is not the total vertical reaction force that is acting. This is not F y. But r x and r y come into picture because of this radius is on either x and y directions. The m is the bending moment that acts at the edge. So, there what we do is simply we take bending moment due to distributed loads due to inflation which is divided into two parts. That is what we do this and this. As if there is a distributed load like that here. This is the result of the bending moment due to the distributed load and that acts in the opposite direction. Ultimately, you have a bending at the edge period. Yes, yes. See what is this? What do we mean by distribution of this forces? If you want to understand this, it is again very simple. If you have a doubt, let us say that I have a cantilever beam. Now, I have it is a distributed load that is acting on the cantilever beam. So, there is an action here and there is a reaction at this point. So, we are talking about the same action and reaction here. So, this is something like a cantilever beam when there is an action and a reaction. So, the reaction is in the opposite direction which means it should be in this direction. So, you will have a load distribution here such that it will oppose this moment that is acting here in the same fashion as you have in the cantilever beam. So, the only thing difference between these two is that here we have a cantilever beam within quotes, cantilever beam in sense that it is curved beam and with forces acting. Of course, there are effects of local bending. You can see that there are green in some places there are green and there are as you near the grooves and then you have again red and so on. So, there is a sort of relief here that is that is happening. In other words, in other words what happens is that when it really bends then there is a small lift and so on there is a redistribution and that is why you will see that near the grooves they are not red there is a change. So, there is an inflation pressure that is why the two components or what we give that. No, there is no this p i only one pressure one pressure that is acting this direction. That is the inflation pressure the force the result of the inflation pressure can be divided into two parts or two in the x and y direction. So, what we have drawn here is the inflation pressure. Let us come back here and so we are talking about rolling. So, this is the what we call as the static pressure rolling has a very interesting things that are going to happen when you when it is rolling with respect to contact pressure. Let us see what happens and then we will explain. There is a contact pressure of a rip tire look at that when it this is sudden change. You will see that there is a change between the two contact pressure when it is stationary and you can see the whole thing gets twisted. You see further when it is the same thing with the different limits you would see when it is breaking look at the way the contact pressure now changes when it is traction look at the way the contact pressure changes. So, in other words you can see that let us let us get back to this. So, you can see that there is a there is a change in contact pressure. There is an adjustment of contact pressure why does that happen? That is our next question. We are looking at contact pressure in this is the contact pressure. Now, as I travel as I travel from one end of the contact pressure to the other in other words just look at that contact sorry contact patch this is the contact patch. As I travel from one end to the other there is going to be a longitudinal force we saw that in the last class. There is going to be a longitudinal force goes up and comes down. Remember last time we saw that something like this. We also saw that this longitudinal force reaches some maximum R e remember that we talked about R variation of R in A to B, B to C, C to D, D to E and so on in the last class and this longitudinal force has a very interesting effect. Now, just see how that is infinite element let us yeah that is the that is a longitudinal force. I hope you are able to see one is in the positive and the other is in the blue is in the negative the red is in the positive. So, it goes up goes to 0 in the middle comes up and this is exactly what you see here is what you see in the in this case. But unfortunately since there is no unfortunate here, but anyway the rip all the ribs as you can see here do not have the same longitudinal force due to the construction of the tire as we explain. They do not have the same longitudinal forces they are they are different in different ribs you can see that. Now, the tire so that is the let us yeah. So, the first point is that the longitudinal force as we had seen there is not a constant in all the ribs they are different at different ribs because of which the tire now rotates a bit about the vertical direction. So, that the total strain energy total strain energy becomes minimum. So, in other words this distribution of or uneven distribution of forces causes the tire to adjust adjust or in other words the contact pressure now is such that becomes a minimum that the total strain energy is minimum as a system to like to go to a minimum strain energy and so there is a twist. So, that you can very well see that here look at that. So, it it sort of twist in such a fashion that it becomes slightly more uniform. So, in other words the longitudinal forces that are acting has an effect on the contact pressure distribution itself. And for example, the longitudinal forces which we are going to see in the next class due to braking has further look at that has further effect on the contact. Any questions? Just to summarize what we what we said we will continue this that the contact patch is an important or influences the interaction between the tire and the road and that the contact patch though one would like it to be very uniform is not uniform and that there is a there are some some local effects and there are some global effects which has an effect on the contact patch distribution and that the contact patch is also affected by the uneven distribution of longitudinal forces between the various ribs and the ribs tend to or the contact patch tends to adjust itself. So, that the strain energy is brought to a minimum or there is a redistribution such that the strain energy levels as a system is brought to a minimum. So, there is a small rotation that is as far as the free rolling is concerned. We will look at braking and then go to the contact patch in the next class right we will stop here.


Welcome to NTN Nightly. I am Genelle Norville, this edition's top stories. The transition from the Victoria Hospital to the Owen King EU Hospital complete. St. Lucia records five new cases of the coronavirus and the government of St. Lucia ramps up efforts in the fight against COVID-19. Hello and thank you for joining us as we bring you the latest developments. It has finally happened the Owen King EU Hospital is fully open to the public. More in this report from Glenn Simon. Well, it's now official and there was no holding back the elation and emotions of staff as they ended one chapter to begin another. Victoria Hospital has officially transitioned to the OK EU Hospital. Even the Minister for Health could not hold back her sense of relief. I feel elated. I really feel elated today. I went to Victoria Hospital this morning and, you know, I saw the ambulances coming and going picking up patients and, you know, back and forth. And it was really, really, you know, refreshing. It was exciting. It was just, you know, I just felt it's almost like you feel liberated that now we are out of Victoria Hospital and we are into our new hospital, our OK EU. President of the Solution Nurses Association, Alicia Baptiste, said this move left her nurses with beta-sweet emotions. Because most of us were trained at Victoria Hospital and it is our home for many, many years. So leaving it this morning, for me, it was really, really deja vu. But let me just say on behalf of our nurses that this is a move well overdue. An energetic and highly motivated staff, decked out in their respective team colours, were busily implementing the action plan. They were first blessed, provided with breakfast and had a rainbow to guide their day. You have the different teams. You have the transport team. You have the command teams. And then you have the teams who will be actually moving the patients. So we're very happy this morning and we are ready to go. We are very happy about this move. We have waited a long time for it and we are going to make it work. It will work and things will improve. With the suspension of elective surgeries and outpatient clinics, VH had its smallest census of patients with only 45 patients to be transferred to the OK EU H. The move was successfully coordinated via a command and sequencing centre manned at the Victoria Hospital with a sub-command post at the OK EU Hospital. This is the command centre at the Owen King EU Hospital and what we do here, we are responsible for ensuring that the patients are received safely and triaged to their appropriate ward and bed. So once the patient has left Victoria Hospital, Sister Octav will get a phone call informing her that the patients left and we then inform the wards here and the command post when the patient arrives. So if there are any issues on ground, it is channeled up to us here in the command centre and if there's need for external support from Ministry of Health or other services or agencies, we also contact them externally to come on board to ensure that the move is successful. We determine which patient goes next. This sequencing centre was managed by nursing director Ruf Regis Adesanya who orchestrated the overall move. She said the move was guided by the international criteria for patient move. So for the past two days, we've been doing assessments of all of the patients to be moved and to determine how we sequence them. What we've done is we've ensured that the hospital, whether it's Victoria Hospital or OK EUH, is not overwhelmed so we're only sending out from one unit only one patient at a time and receiving on any unit one patient at a time. By 12 noon on the move day, 22 of the 45 patients were already transferred to the OK EU. It's been going very well, exactly to plan. I know other persons but we would be under pressure and look like we're ready to crumble and you don't see that at all. So all of the years of planning and training has actually paid off. The Owen King EU Hospital has now experienced many firsts from the first patients in ICU, on the wards and in A&E. The first babies in the special care baby unit, the first surgery and the proud mother Daria Peter gives birth to the OK EU's first bouncing baby boy, Darian Owen Peter. As a mark of respect, nurses lined the hallway at the OK EU to show respect to sister Ruth Regis Addisanya for her remarkable leadership in planning and executing the successful transitioning effort. Reporting for the Ministry of Health and Wellness, I am Glenn Simon. St. Lucia has recorded five new cases of COVID-19, one of which confirms the existence of local transmission of the virus in St. Lucia. Prime Minister of St. Lucia, the Honourable Alan Chastney during a press conference aired on NTN on Sunday 29th March 2020, urged members of the public to stay indoors and continue protocol as stipulated by the Department of Health and Wellness for their own safety and the safety of their loved ones. Anise Antoine has the details. On Sunday, March 29th 2020, the Israelong Laboratory at the Owen King EU Hospital reported a total of five new cases of COVID-19. This now brings the total number of cases recorded nationally to nine cases. Case one is a 24-year-old female with travel history to New York. She was quarantined at home and presented at our facility on March 27th. Case two is a 45-year-old female with travel history to New York who presented to our health facility on March 24th. Case three is a 47-year-old female with recent travel history to Barbados and Dominica. She presented at the health facility on March 27th. Case four is a 36-year-old male who had travel history to Barbados and presented to our health facility on March 27th. Case five is a 74-year-old female with no travel history, unknown contact with an individual with travel history. She presented at our facility on March 27th. Chief Medical Officer Dr Sharon Belma George noted that Case five points to the existence of local transmission of COVID-19. Aggressive tracing of the contacts of these cases is currently underway by health teams dispatched to the communities of interest. The Ministry of Health has observed that all of these cases were captured through our community respiratory clinics. This highlights the usefulness and effectiveness of these clinics and streamline COVID cases to care in a timely manner. As of the week of March 23rd, St. Lucia commenced national testing for COVID-19. This reduces our reliance on the Caribbean Public Health Agency for testing. Achieving this national capacity has allowed the review and adapting of our national testing protocol to widen the number of persons being tested as well as to shorten the period of time within which results are received. In an effort to better position St. Lucia to respond to COVID-19, the national healthcare system has been adapted to allow for a more robust system. The 311 hotline is now available to provide general information on COVID-19 and access points for care and support. As of Monday, March 30th, the service will be made available for seven days a week and shall function from 7 a.m. to midnight daily. The Prime Minister of St. Lucia, Hon. Alan Shah's name made an appeal to the public to abide by the measures being put in place. Corona does not discriminate. There are many young people dying from this as they are elderly people. And we can't continue to believe that we're immune from what corona offers us. And some of us are, but there are many of us who are not. And the only way that we're going to defeat corona for now is by self-quarantining and by practicing social distancing. Now, the Prime Minister of Singapore put it extremely well this morning when he said the off-ramp to corona hasn't been found yet. That what we're all attempting to do in the world is to flatten the curve, slow down the introduction of cases in order to allow our very capable and very brave medical staff to treat you. The Prime Minister also noted that an additional 11 respirators have been purchased to aid in battling the COVID-19 outbreak. Persons with flu-like symptoms can access care at their closest respiratory clinics. The five existing respiratory clinics are at the Grizzly Polyclinic, the Lacklery Wellness Centre, the Viewfort Wellness Centre, the Denver Hospital and the Souffre Hospital. Clinic services are available at the Victoria and St. Jude's Hospitals and this is to be utilized by persons with respiratory issues requiring care outside the normal hours of operations at the clinics within the community. From the Government Information Service I am Anisia Antoine reporting. This is NTN Nightly. Stay with the broadcast. We'll be right back. Wash them right With soap and lots of water Get between fingers Get under the nails Go above the wrists Do this for no less than 15 seconds Rinse properly Try with a clean towel If there is no water Do the same washing motions with an alcohol-based hand sanitizer containing at least 70% alcohol Wash your hands Wash them right This message brought to you courtesy the Bureau of Health Education of the Ministry of Health and Wellness. Welcome back. Amidst the confirmation of local transmission of COVID-19 in St. Lucia, Prime Minister the Honourable Alan Shasne has implemented several new measures. This disclosure was made at a press conference aired on NTN on Sunday 29th March 2020. The Prime Minister explained that the move was necessary to ensure the safety of all St. Lucia's. Acting Police Commissioner Milton Daisy assured the public that members of the Royals in Lucia Police Force would be out in full force ensuring strict adherence to the new stipulations. More in this report. The confirmed case of a 74-year-old female with no travel history or known contact with an individual with travel history according to Chief Medical Officer in the Department of Health and Wellness, Dr. Sharon Belmar George points to the existence of local transmission of COVID-19 in St. Lucia. Prime Minister the Honourable Alan Shasne cognizant of this and noting that a number of individuals have not been following the required protocols has implemented new measures. I have to say to all of us that I don't think any of us would be surprised when I say to you that we have not done a good job of making sure that we're all doing the right things. I mean the government has made the resources has put all of the laws in place has increased the number of policemen out in the field but many of us have just refused to adhere. There are still examples of people going to bars. There are still examples of people going in crowds to the beaches. There are many operations that have continued to operate flaunting what was required by the government. So this afternoon I have to announce that we are going to have to put more stringent regulations in place. So one, we are going to extend the curfew which was from 11 to 5 o'clock in the morning 11 o'clock at night to 5 o'clock in the morning and as of tomorrow it will be from 8 o'clock at night until 5 o'clock in the morning. Secondly, that we're going to extend the period of quarantine which was due to end around April 5th we're now going to extend it to April 14th. And the third part to this is that we're going to suspend all liquor licenses in the country and so anyone who is going to be operating a bar or a restaurant other than a drive through or take out will be in breach of the law. With me is the commissioner of police and he'll be speaking shortly but I've asked him to strengthen his staff and also their level of tolerance. And again I'm appealing to solutions one more time. This is for you. This is for all of us. Acting commissioner of police, Milton Daisy said it will not be business as usual. Police have warned you and the coming week is not a time for warning and serious about it persons will be arrested. The prime minister has assured me that the fines would be put in place as of tomorrow so persons would be... I am not in a position to say what fine it is that would come from cabinet however I could assure you that you can be arrested from tomorrow there would be at a minimum of 72 hours in and please note also that the magistrate the court is not sitting however we have access to the magistrate who has the power to extend your stay in the police station. The custody suite that is at central police station is available. I have ordered that it be empty so that persons who were arrested and were in there have been taken to Babono, Marsha and Grozile police station just to make that space available for persons who feel to comply. I must report that on Friday that is past Friday at 2 am two persons were arrested in Grozile for feeling to comply with the curfew. They had been charged and were granted bail however I could assure you that in the coming days it would not be so easy. The acting commissioner also explained that a number of measures have been taken by the police. I must also report that one Vesla boat had been seized by the marine police. I commend them for for such action and that boat is impounded with them. I must also report that the police we were busy going out there in search of persons that had come in from neighboring matnik and who had skipped well. Obviously they came in unlawfully and therefore were not in quarantine. We have since brought in some of those individuals into quarantine and I must inform also that we have put together two extraction teams made up of 10 individuals, one in the north and one team in the south and this team would be working directly with the Ministry of Health in identifying persons and then taking them into quarantine.  So everything that is necessary to prevent that spread and these officers I must also inform you that they are from the SSU department. Members of the public are urged to abide by the new measures put in place, not only for their safety but for the safety of all. For the Government Information Service, I am General Norville. That brings us to the end of NTN Nightly. Join us next time at 7pm before we repeat at 7am. You can also catch up with us anytime on the St. Lucia Government Facebook page or YouTube channel. I am General Norville.