In our conversation about work, one of the shorthand simplifications for work that we had come up with was called boundary work, which is the work associated with a moving boundary. And what I would like to do now is generate an even more specific list of shorthand simplifications for boundary work specifically. So let's start a list called simplifications of boundary work. And I will bring over our definition of boundary work just to remind us of what our boundary work actually is. You don't want to get too caught up in the simplifications. So for simplification number one, let's consider an isochoric process. In an isochoric process, that's one where the volume doesn't change. How does the integral of pressure with respect to volume behave? Well, if there is no change in volume, there is no boundary work. I mean, if dv here is zero, then work is zero. Doesn't matter what the pressure is. Neat. Boundary work is zero. So item number one, done. Cool. Let's make another property constant. What if we were considering an isobaric process instead of isochoric? Change in pressure is zero instead of change in volume is zero. Well, if our pressure is constant, it's going to come out of our integral. If it comes out of our integral, we're left with the pressure times the integral of dv, which is just delta v, which means that I would have pressure times delta v from one to two. Therefore, pressure times v2 minus v1. Okay, next property, let's consider an isothermal process. In an isothermal process, the temperature doesn't change. That's time job. The temperature doesn't change. Upper case t. Well, if we have the integral of pressure with respect to volume from v1 to v2, then in order to simplify this for an isothermal process, we have to have some way of relating pressure to temperature. And I don't have a convenient way for doing that in all cases. But I do have a convenient way of doing that for a specific case. That is the case of an ideal gas. So I will write this as isothermal asterisks of an ideal gas. And now we can recognize that for an ideal gas, pressure is related to temperature through the ideal gas law. Pressure times volume is equal to mass times specific gas constant times temperature. So I could say pressure is equal to mass times gas constant times temperature divided by volume. And if I plug that into my integral, I would have the integral of mass times specific gas constant times temperature divided by volume, d volume. And when I try to figure out how that integral is going to simplify, I should start with bringing out our constants. The mass is constant because in this process, I'm assuming that I have a closed system, then the specific gas constant will come out because it's a constant and the temperature will come out because it's an isothermal process. And then all I have to do is simplify the integral of one over volume, d volume. And remember that the integral of one over x dx is the natural log of x. So I'll write this as mass times specific gas constant times temperature times natural log of volume evaluated from V1 to V2. So this would be m times r times t times the natural log of V2 minus the natural log of V1. Then because of our logarithm rules, I can say mass times gas constant times temperature times the natural log of volume 2 over volume 1.  Because remember from our ideal gas law, mass times gas constant times temperature is equal to pressure times volume. So I basically have three ways of writing this out. I could say mrt times the natural log of V2 over V1, or I could say p1v1 times the natural log of V2 over V1, or I could say p2v2 times the natural log of V2 over V1. All three forms are valid. I will also point out after I get rid of this, that because mrt can be written as p1 times V1, that is another way to think through this simplification step here. If you didn't want to just treat the masses being constant temporarily to bring it out, you could approach it by considering the pressure times the volume again. Point being the boundary work for an isothermal process of an ideal gas can be simplified into mrt times natural log of V2 over V1. Of course, if you wanted to use moles, you could say the number of moles times the universal gas constant times temperature times natural log of V2 over V1, or pressure times volume times the natural log of V2 over V1 provided that you use pressure and volume at the same state point. So isobaric, isochoric, isothermal, let's let's throw in one more. And for this one more, I want to simplify for a general type of problem. And that general type of problem is going to be a polytropic process, a polytropic process, if I open up a new page here, I think is easiest to get your head wrapped around if you consider what we've done so far. If you were to plot out pressure with respect to volume, and recognize that the work is the area under the curve, we started by considering an isochoric process, which would be a vertical line. And we said the area under that curve is zero. Great. Then we considered the next easiest case, which is a horizontal line. Great. That isobaric process is just going to simplify to a rectangle. You have pressure multiplied by the width, which would be V2 minus V1. The next simplest case is going to be a straight line between the two. But we can actually characterize more than just a straight line between one and two. What if we were to consider any process that has a curve that bends the same, we can describe all of these curves at once provided that the amount of change in slope is constant. What I like to think of as the curviness of the line, the bend of the line, that curviness of the line has to be constant for our process to be described with the expression that we get in a polytropic process. Polytropic, many curves, all of those are described by this. Pressure times volume raised to an exponent is constant. For our polytropic processes, if we can figure out n to represent a process, then our polytropic process simplification of boundary work will be much easier to apply than trying to integrate from scratch all over again. And this is also convenient because I can come up with some common n values. This n value is the polytropic exponent, and some common values for n include 0, 1, and infinity. When n is equal to 0, then volume raised to the 0th power is just 1, and I have pressure is equal to constant. So n is equal to 0 is equivalent to an isobaric process. For n is equal to 1, I have pressure times volume is constant. And that should also be a little bit familiar, because the process that we analyzed before this was a process where we had a constant temperature of an ideal gas. And in that situation, we had a constant mass, we had a constant gas constant, and we have a constant temperature, so pressure times volume is constant. Because constant times constant times constant is still just a constant. So a polytropic exponent value of 1 is representative of an isothermal process of an ideal gas. The next common value is what happens as n approaches infinity. Well, as n approaches infinity, the importance of pressure becomes less and less important. So we could say at infinity, I mean, if you think of infinity temporarily as a number, we could say we have an isochoric process. So these are kind of our touchstones. We can use the relative value of n to think through what sort of behavior is actually happening in this process. And I will actually add one to this list. You're not going to be familiar with it yet, but you will be in the future. And that way, if you come back to this, say hypothetically, when you're in thermo two, and you're trying to figure out the boundary work associated with a gas power cycle, and you've forgotten these simplifications for boundary work, so you're watching through this video again, when n is equal to k, which is our isentropic exponent Cp over Cv, that's equivalent to an isentropic process. So if we can simplify the boundary work for a situation where the pressure times volume raised to the n is constant, then I can plug in any situation where I know n, the n value into our boundary work, and come up with the amount of work associated. By the way, I will also point out this is pressure times the quantity volume to the n, not pressure times volume quantity to the n. That's in a very important distinction. It is pressure times quantity volume to the n. Okay. So I will jump back to our definition of boundary work, the integral of pressure with respect to volume, and I will plug in our relationship for a polytropic process. That's a situation where the pressure times the volume raised to the n value is constant. So I could say pressure is equal to constant over volume to the n value. I'm saying P can be written as the constant divided by volume to the n. And I really only remember the power rule from Calc 1, so I try to do everything with the power rule that I possibly can. So I'm just going to write this as constant times volume to the negative n. I mean remember that multiplying by one half is the same as dividing by two. I don't know if that helped, that reciprocal, multiplying by the reciprocal of a quantity is the same as dividing by that quantity. So then I have the integral of constant times volume to the negative n, d volume, integrated from volume one to volume two. And constant is constant, so constant comes out. And I have constant multiplied by the integral v1, excuse me, the integral volume to the negative n, d volume. Now what is the integral of volume to the negative n power with respect to volume? It's cool, I'll give you a second. It's kind of hard to wrap your brain around. The first time you're considering a situation like this, it's easiest to consider if you just step back to the integral of x to the a with respect to x is going to be one over a plus one times x to the a plus one dx. If a was two then you have one over three x to the third. Okay, so my integral is going to be constant multiplied by one over a is negative n, so I have negative n plus one times volume to the negative n plus one and I'm evaluating that from x1 to x2. And then I would have constant times one over negative n plus one times v2 to the negative n plus one. Isn't that fun by the way?  Remember that, it'll be helpful later. Negative n plus one, just a fun thing to say, times v1 to negative n plus one. That's plus plus. That would be our programming language, form of our knowledge of work. So constant times one over negative n plus one times v2 to the power of negative n plus one minus one over negative n plus one times v1 to the negative n plus one. Okay, now I'm going to bring out one over negative n plus one at which point I have constant over negative n plus one times v2 to the negative n plus one minus v1 to the negative n plus one. And then I'm basically out of space, so I will start a new page. And this was saying boundary work of a polytropic process is constant over negative n plus one times the quantity v2 to the negative n plus one minus v1 to the negative n plus one. Well, constant is kind of unhelpful here because we didn't actually relate that to anything else other than describing what a polytropic process is. And the description was pressure times volume to the n is constant. So let's get rid of that constant by plugging in pressure times volume to the n. That would be pressure times volume to the n divided by negative n plus one times v2 to the negative n plus one minus v1 to the negative n plus one. Okay, now which pressure and volume do we actually use here? Is it one? Is it two? The answer is doesn't matter so long as they're evaluated at the same point. So I could say p1 times v1 or I could say p2 times v2, but I could not say p1v2 or p2v1. And just to make my life a little bit easier, I can actually distribute that back inside the parentheses at which point I would have one over negative n plus one multiplied by pressure times volume to the n times v2 to the negative n plus one minus pressure times volume to the n times v1 to the negative n plus one. And remember, I can plug in either state point so long as I do it the same for both. So when I'm bringing it inside the parentheses and I'm multiplying it by v2, I'm going to plug in my v2, excuse me, I'm going to plug in my state two properties. So v2 times v2 to the n multiplied by v2 to the negative n plus one. And then I'm going to subtract p1 times v1 to the n times v1 to the negative n plus one. And remember, when I'm multiplying a quantity to an exponent times the same quantity to a different exponent, I can combine the exponents together as an addition or subtraction process, like x squared times x to the third is equal to x to the two plus three. So I could write this as one over negative n plus one times the quantity p2 times v2 to the power of n minus n plus one minus p1 times v1 to the power of n minus n plus one. And how does that simplify? You're right, n minus n is zero. One is one. So I have p2 times v2 to the first power minus p1 v1 to the first power. Therefore, the boundary work can be written as p2 v2 minus p1 v1 divided by negative n plus one. So I write it as negative n plus one because I think that that phrase rolls off the tongue real well. It makes it easy for me to recall that when I'm working through a problem and I need to pull out the boundary work of a polytropic process, as opposed to flipping back through my notes, I can just remember it's p2 v2 minus p1 v1 and then something, what is it? Oh yes, it's negative n plus one. Neat. It is not negative one plus n because that's not nearly as fun to say as negative n plus one is also not one minus n because then I don't remember if it's n minus one and one minus n. It is easiest to remember if you can just remember negative n plus one. If it becomes muscle memory, you don't even have to remember it. So I will write this down back under my simplifications for boundary work. I had a polytropic process and that problem and that polytropic process is one where the pressure times the volume to the n is constant and the simplification is boundary work is v2 v2 minus p1 v1 to the negative n divided by negative n plus one. Okay. And while we're here, I will also point out that in some cases, instead of plugging in total boundary work, it might be more convenient to plug in specific boundary work. And remember that specific boundary work is total boundary work divided by mass. And if I were to bring that inside of my equation, I could write that as pressure times dv where v is specific volume. So I could say the specific boundary work is equal to the integral of pressure with respect to specific volume from specific volume one to specific volume two. And then the simplifications would become for an isochoric process, the boundary work, the specific boundary work would still be zero.  For the isothermal process of an ideal gas, we would just have r times t times the natural log of v2 over v1 or p1 times specific volume multiplied by natural log of v2 over v1 or p2 v2 specific volume two, that is pressure two times specific volume two times the natural log of v2 over v1. And in the polytropic process case, it would be p2 times specific volume two minus p1 times specific volume one. And those are our common simplifications of boundary work. That doesn't mean that these are the only simplifications of boundary work, but these are the ones that we're going to encounter the most.


Welcome to lecture series on advanced geotechnical engineering offered by Indian Institute of Technology IIT Bombay. This is a lecture which discusses about the entire course series which we have seen in seven modules and we try to look into the different areas which are there in the geotechnical engineering and this course also has you know very well organized excellent material basically to create an impetus and also a knowledge towards the geotechnical engineering aspects. So this is the course on advanced geotechnical engineering and this course actually has seven modules and in total about there are you know including this lecture there will be about total 60 lectures. In module one we have discussed soil composition and soil structure and basically we have tried to cover this lectures in length from you know L1 to L11 where the formation of the soil types of soils and their characteristics were discussed, particle sizes and shapes and their impact on engineering properties, soil structure that is the fabric arrangement, soil fabric and clay mineralogy and soil air water interaction, consistency of a soil, soil compaction and concept of effective stress were discussed under the module one. And this in this module we also have discussed about number of work examples and also solved number of problems which are pertinent to this module. So in module two the title of the module is permeability and seepage, in this module the lectures were covered from L12 to L18 and the contents basically are you know a property of a soil permeability and a condition seepage were discussed in length and seepage force and effective stress during seepage were you know discussed and Laplace equations for one dimensional and two dimensional conditions and inside for three dimensional seepage was given and flow net methods conventional as well as the methods by using the demonstration examples from the GeoStudio 2012 using CPW program were also shown and then also we discussed about eneosotropic and non-homogeneous conditions and confined and unconfined seepage conditions and in this module along with the theory the number of worked examples have been solved basically to give insight into this particular important module where the permeability and seepage are concerned. In module three the compressibility and consolidation particularly these lectures are covered from L19 to L29 and where in the stresses in soil from surface loads and Terzaghi's one dimensional consolidation theory and application in different boundary conditions and especially the conventional Terzaghi's theory is instantaneous loading but in case of ramp loading how this can be done which has been discussed and determination of the coefficient of consolidation and also we discussed about the normal and over consolidated normally and over consolidated soils and compression curves and secondary consolidation and radial consolidation and then you know we introduced the Barron's theory and then thereafter the settlements of the compressible soil layers for one dimensional consolidation as well as considering the one dimensional as well as the radial consolidation was discussed and methods for accelerating consolidation settlements especially in this we discussed about preloading alone and preloading with sand drains and preloading with free fabricated vertical drains and we also discussed about some novel methods like vacuum consolidation alone and vacuum consolidation along with prefabricated vertical drains and these methods were basically to give insight into the methods for accelerating consolidation settlements particularly the soils which are actually soft in nature and when we require the excess pore water pressure to dissipated in a short duration of time and this you know method was this particular concepts are really will be helpful. Then module 4 it deals with the stress strain relationship and shear strength characteristics of soils and in this module the lectures are covered from L 30 to L 39 and basically the stress state was introduced and Mohr's circle analysis particularly pole and principal stress spaces were discussed in length, stress parts in PQ space and Mohr Coulomb failure criteria and its limitations and correlations with PQ space and stress strain behavior and isotropic compression and pressure dependency and confined compression and large stress compressions and definitions of failure and interlocking concept and its interpretations and drainage conditions especially with the triaxial behavior and connected with the stress parts for unconsolidated and unrained and unconfined compression test and consolidated and unrained and consolidated drain test were discussed and the stress parts in triaxial and octahedral plane were introduced and elastic modulus from the triaxial test how to interpret elastic modulus from triaxial test were discussed and then we also have solved some couple of work examples basically to give insight into this module which is on stress strain relationship and shear strength of soils. Further in module 5 the stability of slopes which is discussed in L 40 to L 46 that is lecture number 40 to 46 and in this the stability analysis of a slope and finding critical slip surfaces, sudden drawdown condition and effective stress and total stress analysis and seismic displacements in marginally stable slopes and a concept or you can say that introduction to reliability based design of the slopes was attempt was made and in-depth discussion on the methods for enhancing the stability of unstable slopes this was actually discussed basically the methods like slope stabilization by piles and the recent methods like biotechnical stabilization and some methods like slurization by soil lanes and stabilization of a slope by piles, vertical piles. So these stabilization methods were discussed and basically in this what are the different methods of slope stability analysis methods and how these methods can be used for determining the factor of safety of a given slope and what are the merits and debilits of different methods which are there in the for analyzing the slope and also a detailed discussion on the enhancing the stability of unstable slopes was covered. In module 6 a brief discussion on L 47 to L 49 that is three lectures which was made on buried structures basically here a load on pipes and Marston load theory for rigid and flexible pipes and trench and projection conditions were covered and minimum cover required and pipe flotation and also liquefaction issues were discussed. Interestingly a recent case study which actually happened in one of the power plant sites was actually discussed and how these situations this type of failure situations can be averted was demonstrated through a Geo studio to 2012 analysis as a case study example. In module 7 finally a detailed discussion on geotechnical physical modeling was discussed and wherein in principle the lectures run from L 50 to L 59 where all the aspects which are required for geotechnical physical modeling were discussed and where in physical modeling methods application of centrifuge modeling and its relevance to geotechnical engineering and centrifuge modeling of geotechnical structures with actual live examples of centrifuge based physical modeling which is actually activities which are being carried out at IIT Bombay are covered in length and then also an attempt also has been made to bring out the relevance of geotechnical based centrifuge based geotechnical modeling for understanding the behavior of geotechnical structures and for different examples like a slope stability problem and bearing capacity problem and also like retaining wall problem has been discussed and then the merits and demerits actually have been awarded. So in this particular course as we all see the course is actually very much relevant and has got lot of prominence not only in India but also in many places many parts of the world and as far as the India is concerned where we have got varied soil deposits from north to south and east to west in India particularly if you look into this we have alluvial deposits along the rivers and particularly where we have got verbals and then we have about 6300 kilometers of you know coastal belt and where in we have about you know the very soft soils the marine deposits which are actually having normally consolidated soils throughout the coastal belt they are there and measure to the ports and harbour structures or measure activities which are actually take place they are actually on this particular marine deposits and then towards the northern part of India where we have got the border deposits or a silt blown areas which are actually there in Delhi and Uttar Pradesh and other parts of India and similarly towards the north east we actually have got the soils which are of the order of you know some sort of desert soils and we also we have some laterites and lateritic soils and towards the you know Kerala or this side we have about the laterite soils again here in this part of the region and then we have we have got a you know huge chunk of area which is actually covered with black cotton soil deposits which actually has got very typical behaviour of having you know the swills the swell shrink behaviour and then we also have you know out of this if you look into this there are many areas which are actually classified as vulnerable to you know earthquakes. So the particularly the relevance of you know the soil mechanics or geotechnical engineering has got lot of prominence because you know some of the techniques which are actually adopted in one region may not be adopted may not be you know applicable in other parts of the country. So there are different challenges which are actually there like typical challenges in geotechnics basically if you look into it we have the conditions of the roads particularly on expansive soil deposits in Majapurayesh and Maharashtra can cause lot of distress or rutting and other failures and then with increasing in urbanization there is a possibility that the municipal salt waste generation actually takes place very rapidly and this actually has been projected that you know the generation of the municipal salt waste is on the higher side in urban areas and as on date with unaccounted records it says that you know 10000 tons per day is collected in place like Mumbai and similarly the storage of this waste if it is not proper there can be failures like this which actually can cause you know very you know a situation which is very difficult to manage and then we have got number of stretches of the long stretches of the railway tracks running on weak formations and particularly with an increase in the need for you know the increasing the speed of the trains there is a need for you know arriving at the proper track underlayment structures where in you know one of the some of the typical methods which are actually you know modern methods or novel methods which are required to be adopted so that the fouling of the ballast can be prevented and also the resistance which is required for the high speed train movement can be ensured by putting some sort of you know a strengthening measure and similarly we can also think of you know also considering the scarcity of the natural materials one need to evolve at materials which are actually can be substitutable like railway embankments which can be constructed with fly ash as a core material or a coal ash a coarse coal ash as a coal material or some reduction in the thickness of the aggregate layer if you are able to achieve then there is a possibility that the huge savings can be achieved. In addition to that particularly in elite terrain particularly where the trains run through these several cuttings and embankment sections there is a possibility that you know these during monsoons particularly because of the loss of the suction you know makes it actually to have reduced shear strength and this makes many slopes to fail and also have got if these slopes have got huge rock boulders and there is a possibility that this lead to the dislocation of rock boulders and which leads to you know failure as well as you know some of the cases have been reported wherein they end up you know in meeting with the targets which are actually nothing but the transportation vehicles and we also have some highway structures where actually because of the flash floods and because of the some instability problems so there can be unstable sections can be avoid. So this is an example some of the typical examples which actually show you know the requirement of some of the modules which are actually covered so here it can be seen that a landslide in a Hong Kong area where you can see that the area which is you know subjected to a high-range buildings and when it is subjected to groundwater table changes within the slope or if there is a burst of pipeline that can actually create an instantaneous you know ingress of seepage and can create an unstable instability and which can be hazardous like the way it is actually shown here. So this can actually lead to a distress which actually can create you know the transportation infrastructure can get affected or also the surrounding or building which are actually very close can be badly affected. Similarly the construction on soft soil particularly where we have got say a soft ground if that soft ground is not treated properly and even if it is the bund is constructed with a proper quality control but however this type of failures can actually can happen this is one of the case study which is actually reported in 2006 where you know a reinforced soil wall on a soft clay is subjected to failure because of the distress which is actually reported a base failure which has been reported where a 170 meters of section of wall subjected to failure. So these type of things can be aborted by a proper understanding about the compressibility and consolidation behavior of a soft soil and then after adopting an appropriate method and then then a superstructure that is actually wall can be constructed on that. This can have a better performance of a structure which can be constructed on such type of soils. And this is a typical you know geogrid reinforced soil wall failure at Seol Korea this actually happened in 2004 after you at all in 2004 and here what actually has happened is that this is called a reinforced soil wall section this is called reinforced soil zone and this is called the backfill zone. So here it is generally preferred that you know at least in the reinforced soil zone it is preferred that we need to have very you know highly permeable soil but in case of non availability then you know there is an if you are actually using soil with high percentage of fines in such situations what will actually happen there that when there is an ingress of water there will be an increase in positive pore water pressures and this increases actually the forces in the reinforcement layers and which was actually not designed for and can lead to failure. So this is one such example a segmental block failure wall failure is actually shown here. This is a case which is in 2001 where in the slope symmetry problems which are actually reported and this is one of the trains actually met with an accident where which actually lead to the severe rock fall as well as you know the damage due to slope instability problem and this is at the similar location at the same location we are close to Ratnagiri station where we have a typical railway embankment failure where in 2004 or 2005 because of the heavy rain which actually occurred and this led to the entire section of a slope of embankment of about 24 meter subjected to a failure and where in you can also see that the restoration methods which are actually have taken place subsequently have also been subjected to failure and this the track which is actually here which is shown was observed to settle in 2005 by about 1.7 meter subsequently by another 0.8 meter. So in total they actually have sunk by about 2.5 meters and this actually you know has led to several issues particularly with the instability problems for that cut and fill embankment which was actually constructed at that particular site. And this is a typical slope failures particularly in Igatpuri region where in the monsoon these are actually prevalent because of these situations which actually can or can be hazardous for the journeys to take place in this direction. So appropriate methods need to be adopted basically to avoid these dangers and in this particularly here in urban areas particularly when you have got the gabion walls and there can be possibility that this gabion walls can undergo deformation that means that this is the one wall actually moves away from the backfill you can see that how the gabion wall deforms and similarly here when we have got let us say a failure surface actually passes you know below the retaining wall then there is no need for you know this retaining wall because you know this retaining wall also be subjected to failure. So in such situations there is a need for maybe adopting a deep slope stabilization techniques particularly in this situations can be piled slopes is one piled or if the retaining wall is provided with the piles these piles can actually can increase the you know the slope the factor of safety against the slope stability failure. Similarly when this is a case study where failure due to excavation in the urban areas particularly when you are actually doing very close to the property lines these property lines this when the excavations made the amount of excavation actually can cause a distress to the existing structure foundations like the foundation can actually can be a shallow foundation or a deep foundation but can lead to eccentric or increasing stresses and these stresses cause you know a distress in the existing buildings and can lead to you know collapse of the buildings because of the proper care or proper you know protection measures are not taken this is one such case where the failure actually happened because of the excavation in the you know area which is actually close to you know having a five storey building. And this is a failure of the dam in Spain where in a breaching failure was reported this is after Eichold 1995. So this is this type of things can actually lead to a catastrophic dangers of submersion of the flood waters so these things need to be addressed because you know this type of case studies were also reported in New Orleans in 2006 when the you know when Mississippi River war topped the levee and it got subjected to entire New Orleans city was actually submerged in the water and this actually caused a lot of destruction. And this is in Singapore particularly when a particular this is a deep excavation which actually has taken place and the idea of interest is that this building needs to be protected and is required to be protected because any excavation any change in the groundwater table can lead to settlements in this building. And so here in this is a soil nailing type you know shore protection system was actually adopted basically and then the surrounding area is actually is granted basically to you know increase the stability and to prevent any you know loss of support so that this existing building will not actually experience any distress. So then this also basically this a proper shoring system also allows you know to adopt and construct a construction in that area whereas has been air marked for development. Similarly this is a type of shore protection system which is being adopted in India and many places very. So in this the piles are actually placed closely and we can see that these are the you know beams which are actually connected to anchors so three level anchors were placed these anchors actually prevent the wall from undergoing rotation. So these anchors will ensure the stability to the you know this retention system and then this is actually area which is actually open for development and this is a famous you know 35 meter deep Nikoli highway collapse in Singapore so this is actually shown this type of situations can actually can happen when we actually have got you know the failure of some struts and leading to some retention system or shoring system which actually has been in place. And this is a typical road which is actually shown but nowadays with the requirement of need for development of underground railway stations or underground networks there is a need for you know creating void spaces below the you know populated areas. So this is if you take a section below this is actually a underground substation which actually being developed by a technique which is allows to create void spaces so these spaces are used basically to you know maneuver the you know the trains or underground systems and these are also nowadays are being used for putting number of underground utilities and communication cables and other accessories. And this is a typical example of cracking of landfill capping system and this is particularly when the waste which is actually covered and when it is subjected when the waste beneath the landfill is subjected to some movement because of the ongoing by decomposition what actually happened is that the cover system including the liner inside the lining system inside the cover system is subjected to distress and is subjected to both you know desiccation cracks due to drying and wetting which actually takes place and as well as you know bending cracks which actually can lead to you know the loss of integrity and can cause you know gas migration from the sealed landfill into the surrounding environment. So this is a typical example in France particularly in area by at a drone landfill and this is after Gauk et al 2010 and this is you know what actually happens is that this is a landfill site in France where you can see that this pipeline is straight at the time of installation but however after certain period of time you can see that this pipeline undergone non-informally settlement that means that this landfill what you see is the cover system which actually has got a cover soil which is about 1.2 meters height or so and then we have got a gas drainage layer and then we also have got you know compacted clay liner system and then there is you know this is the gas drainage layer this is water drainage layer. So this water can actually drain out so that rain water will not enter into the landfill and then this particular clay barrier can undergo tension because the clay can take only very you know maybe not more than 1 to 1 percent tensile strain and once it actually exceeds this tensile strain the bending exceeds this tensile strain the material undergoes tensile crack failure and which leads to the loss of integrity and also leads to the gas migration which actually can take place through the cracks which actually occur because of this deformation. This is the scenario this if you take the cross section the cross section may look like this thing and another you know typical problem which is possible is that the pollutant migration like particularly if you are having a pollutant which actually takes you know let us say a certain amount of time to reach from one destination to other destination but in order to design you know barrier systems particularly vertical barrier systems one need to you know adopt proper physical modelling methods so that you know these systems can be estimated these can be assessed and ascertained basically and the methods can be designed with a performance so that you know this actually lead to a proper functioning of the designed barrier system. So here two examples of one is that LNA PL migration the other one is you know the so called you know gas migration which is actually shown for my gas tank. So this is another example this is the blown up view of the you know this is shown LNA PL release and subsequent so when the ground water table flow it can lead to the contamination and then it can you know take away this you know it can actually promote the migration of LNA PL which actually released inadvertently. So the another issues which are actually there in Japan and many other countries is the earthquakes which actually can occur particularly if you are actually having sandy deposits up to certain amount of fines there is a possibility that you know a momentaries loss of strength can lead to you know a very rapid settlements this is a particular you know photograph where this has been actually taken after the earthquake where it can be seen that this ground floor now looks higher than the original floor level because what actually has been happened that this shop undergone settlement and then settled. So you can see that this is the sunken portion of the building this is the wave side walk which is you know damaged due to the earthquake and particularly here these two roads used to be at same level but because of the distress created due to earthquake this actually has got experienced a failure and similarly when you are actually having a building which is actually designed with on proper you know foundation system then they are actually observed to be tallest building stands as if nothing happened but the systems without any proper system can be subjected to you know a distress which is actually shown schematically in this particular slide. And another the problem is that bursting of the underground pipeline particularly if the pipeline is old or if the pipeline joint failure occurs and this is actually is very repeatedly happening for the past three four years and this can actually lead to you know the destruction which actually shown here and this is a damage which actually has caused to this area because of the bursting of the underground pipeline because here what happens is that these pipelines are operated with certain operation pressures but with increasing a surge in the pressure what will happen is that there will be a burst which actually can take place because the in the surged pressure cannot be you know taken by the damaged portion of the pipe or a weak joint. Similarly this is another example which is you know a similar trend of failure you can see the caving of the road due to the bursting of the underground pipeline. The another typical failure which actually shown is that because of the flooding which actually takes place because doing the reverse and these failure of a bridge pier is actually shown here you can see that how the pier is actually is about to be you know displaced. So you can see that the massive effect which is actually shown by the flowing water on the pier which is actually there which can actually lead to very high amount of scour. So this type of failures can actually occur because these with the loss of confinement can lead to the very capacity failure and can actually have you know the decks can actually settle like this and then can lead to failure. So this is the typical scour problems which are actually shown in number of places and these are very typical in nature and this is in 2013 actually which has happened and the instability problems of the along the hills particularly which actually due to the flash floods and can lead to lot of instabilities and dangers which actually can happen because of this cloud burst and other issues which are actually happening in India and other parts of the world. So this is an example where how the destruction actually has taken away the portions of the buildings and led to the you know severe you know casualties which actually result from the failures. So this is another look of the destruction which actually has taken place so you can see that the round boulders which is actually indicates that the flow of water which is the history of the flow of water can be seen from this here and these are this is the river which is actually flowing through the flowing along these banks and this is a typical landslide which actually causes the road to cut off and the particular number of villages which actually can lead to cut off because of this massive landslides which actually can occur either due to earthquake or due to rainfall or due to some construction activities which are actually taking place in these areas. And this is that you know power plant you know conduit failure wherein you can see that this is before removing the soil a failed pipeline is shown here and this is you know a bean shaped pipeline is actually shown here and this is you know this is another pipeline which is intact but you can see that this pipeline is subject to failure this is because merely because the flowing water actually exerts very high pressure and that led to the pipe buckling which actually has you know induce this failure. And this is a fire safety water tank in one of the construction sites so basically these are these this is actually the used area which is actually designed with a concrete lining it can be seen then you know but because of the some you know instability issues we can see that in the ingress of rain water the how much the amount of the pressure which actually exerted and led to the failure particularly here in this areas and the close look of this you can see that this you know lining actually experienced a severe failure and this is a large fire water storage tank so in this basically what actually happened is that how the uplift of the water can actually create a distress can be seen here the water tank was actually designed for a water table at certain level but when the water table raises because of the ingress of the rain water then there is possibility that what actually happens is that the rain water exerts a very positive pore water pressure on the base of the tank and which actually has led to the bending of this slab you can see that the deformed shape of the slab and this is a barrier you know baffle wall which actually has been subjected to cracking because the bending is actually is maximum at this particular point. See this is another instability problem in landfills particularly when waste undergoes the instant movements within the landfill and these lining systems which are actually placed can lead to failures and which is in a clear example of instability problems in municipal soil waste landfills and these are the typical you know schematic figures of the local instability failures particularly when there is you know bulging of the liner due to lack of support then liner actually moves like this and this can actually lead to failure here and sometimes what will happen is that if you have got a lining system but if it is loss of protection due to this is particularly possible when you are actually having geosynthetic clay liners and when they are subjected to some swill the swell and the shrink cycles and in between they can lose the protected area so that can actually lead to some sort of a you know that portion at the zone behaves like as it is unprotected. So this is a typical you know aerial view of the waste slide which actually was reported by E. Datal in 2000 and the lateral displacements are measured to be up to 275 meters and vertical displacements up to 61 meters and 1.2 million meter cube of the waste was actually observed to move so the lateral displacements up to 300 meters were actually measured and vertical displacements were up to 61 meters were observed and this is another view of you know reported by Stark et al 2000 and where you can see that the distressed area which is of a landfill is actually shown here. So this is a typical you know schematic representation of the failure of ash pond dam as been discussed that these ash pond dams are actually designed you know this is a method which is actually called as upstream method the what will happen is that the first bond which is actually constructed with the you know the soil and then the second bond and subsequent third bond and fourth bond they are actually required to be raised mostly generally with a bond of 5 meters height up to 20 meters or 25 meters height it is the general practice to construct but because of the non availability of the soil or the need for the use of local available material like coal ash or play ash there is a need for constructing this portion of the first stage or second stage or third stage bond with coal ash which has a coal ash as a core material and then surroundings are actually made with you know a clay blended material and which actually has got good erosion resistance so but you know when the water this is a big hydraulic structure when the water is exerts a pressure there can be possibility that this type of instability failures can result because of the seepage problems and these type of problems are also you know can occur when you are actually having even tailings dams or coal ash pond dams. The this particular this particular you know slide which actually shows the problems which actually can come with high speed trains and this is from you know Tokyo Institute of Technology wherein in Japan they have investigated about the effect of movement of high speed trains on the and the bridge pier foundations and particularly when the high speed train traverses on the bridge and the bridge which is actually resting on the you know say sandy soil and these bridge piers are subjected to you know localized liquefaction and then these vibrations are actually sometimes if the piers are closed then there can be interference can actually take place. So in order to study these problems particularly like you know the you know which type of how these you know damages can be prevented and to allow the traversing of high speed trains then there is a need for you know the so called adoption of isolation systems. So in order to design the systems with performance and all then geotechnical based physical model model model studies particularly especially the centrifuge based physical model study can be used. So this is in recently which actually happened along Mumbai Pune expressway in June 2015 wherein because of the instability of the rock slopes there can be a problem which is actually can cause because of the instability occurs due to the detachment of the rock pieces and led to the number of casualties also and these so for to avoid these things you know the proper system need to be in place. So this is actually being discussed to just bring the awareness about the magnitude and order of the problems which are actually there in the advanced geotechnical engineering arena. Similarly with an increase in urban population with generation of the urban waste there is a need for you know proper disposal of the waste for example this is a scenario in some megacities but if these you know waste is actually confined properly and this can lead to generation of good gas which actually can be used for producing you know the at least to electricity to support the landfill activities. So these to be handled properly and apart from whatever the methods which are actually adopted to reduce the waste but there is you know ultimately you know there is land fields are the ultimate disposal methods which are actually for the for disposing the waste. So these are the typical examples how they can actually lead to the order of contaminants which actually can occur and you can this can be seen that this type of you know areas can actually can have the serious effect on the adjoining properties and the generation of the gases can lead to the environmental hazards and contamination of the water bodies beyond the high toxic levels. So these need to be done with you know this comes under the environmental geotechnical area and connecting to the very recent developments you know nowadays which is required to have not only you know you have a foundation but also you know the foundation which actually has to also takes supports the cooling and heating systems within the buildings. So these are actually the part of you know the green buildings or proper green buildings which are actually coming up.  So thermal loads means it can be so the this coupled loading condition basically highlights the need to have a clear understanding about the temperature effects on the mechanical behavior of soil as well as the pile soil interaction. So what will happen when you are actually having a different temperatures on the interfaces and what actually happens on the in the pile soil interface and similarly you know what is the effect of the temperature on the mechanical behavior of the soils need to be understood. So these energy piles concept is actually proving to be see this you can see that this is in the winter and this is in the summer. So wherein it actually use in winter it is used to heating the building and in summer it is used to cooling the building. So this is you know a new concept which is actually been reported by Abiyol Naga et al. in 2015. So this advanced geotechnical engineering area which is actually has got multifaceted interest particularly from you know environmental engineering point of view from the transportation engineering point of view or from the structural engineering point of view to actually have you know construct this high-raised buildings one need to understand about the compressibility consolidation and stress strain behavior of a soil and from the performance point of view in order to understand the behavior all these aspects which are actually sometimes when the proper materials are not available when need for the optimization of the designs when we wanted to improve the performance of the design and then you know then we actually need to to the appropriate physical molding methods and these methods which actually can lead to a betterment in the behavior. So but not all geotechnical failures end up in embracement however most do this is a famous example of leaning tower Pisa in Italy which is you know 400 to 500 year old and which is subjected to a sort of distress because of the consolidation or compression behavior of a clay. So before giving the references you know at the outset the like to thank for patient hearing and I will also like to thank the center for distance education program and NPTEL phase 2 staff for their excellent support and motivation provided for completing this course from time to time. So for giving feedback on this course please contact myself which is actually written here Dr. Ving BVS Vishwanatham, professor department of civil engineering Indian Institute Technology Bombay India and the telephone number and email ID which is actually given here and this is the iconic symbol of Gyanam Parmam the aim of IIT Bombay. So now the some of the references which are actually used in this particular course are given here and these references are not in order but number of references are actually used so this majority of the references are listed here and if any of the references are listed they are actually listed only from inadvertently where could not be added. But here you know Atkinson 2007 mechanics of soils and foundations and thus 2008 advanced soil mechanics Craig RF 2004 Craig soil mechanics and the some of the references which are actually given here they are actually holes and coax interaction to geotechnical engineering which was actually put McCarthy essential essential of soil mechanics and foundations and basic geotechnics and parry RHE this is basically for Mohr circles trespass and geotechnics were actually deferred for you know shear strength characteristics of soil and the wood David Muir wood actually book is actually was you basically deferred for some examples and discussions which are actually made on geotechnical physical modeling and centrifuge based physical modeling. So the geotechnical modeling aspects were actually covered from this particular you know book and the basic soil mechanics book Lamby and Whitman 1969 soil mechanics book with John Willie which is actually used and these are some of the cross references which are actually shown here and then these are some of the references which are actually listed in the literature or which are referred or indicated here and these are the some references Terzaghi and Lamby and Whitman and you know then this the theoretical soil mechanics by Terzaghi 1943 this was referred for some of the in the derivations and then Taylor 1948 fundamentals of soil mechanics this was actually referred and theoretical foundation engineering by Dawes 1987 was actually referred and then again Harza particularly for in the seepage analysis uplift and seepage under the dams in sand this was actually referred and then Eme Har ground water and seepage this was actually referred for discussing about the seepage relevant aspects in the particular module then these are the some references which are actually listed in this particular lectures. So this is you know in slope stability computations according to John Bosz method and this is for felinus method and then you know we also have covered you know the different this is a geo studio 2012 and the excellent software package for calculating the slope stability and CW and also for stress strain we have sigma W for loading conditions this was used and also quick W was also used for simulating some problems on earthquake aspects and then these are the some references chi and you guy 2003 response of flexible pines under laterally linear movement of this sliding layer in landslides and this while discussing pile stabilized slopes were actually referred and landslides analysis and control this again under slope stability aspects and stabilization methods were actually discussed Abrams one this is for this is Abrams one at all 2002 was referred for slope stability and the stabilization methods which is after John Willie and sons and then some of the books which are actually referred are papers which are referred are listed here and this is again the Kramer which is on geotechnical earthquake engineering was actually referred for discussing about the you know the seismic aspects of the slopes and then in the geotechnical physical modeling Jelix and 1969 was actually referred for geotechnical models using hydraulic gradient similarity method and then Barton 1965 this is here consolidation of clay with nonlinear viscosity and this is actually referred in from geotechnic and then there are number of references which are actually listed here which are actually shown here for and then the ground geotechnical engineering ground handbook that is geotechnical engineering handbook that is Grunborn bold mechanic tassion book was actually referred for some serient examples which are actually documented by Professor Smallsick part 3 and part 5 were referred and in case of buried conduits handy loads and underground conduit soil engineering and handy and the Spangler geotechnical engineering soil foundation principle practice which actually referred particularly for handy was referred for the working examples and then theory which is actually relevant to buried conduits or buried structures and then some of the lectures these are actually Spangler and handy soil engineering this book was referred and this is another references and this is on the consolidation settlement due to ramp loading this was actually referred after Shukugan at all 2014 and these are the some of the references which are actually listed which are shown here this is in soft ground improvement. So for you know more details that and feedback on this course the details can be obtained here at this address which is actually shown here this marks the end of advanced geotechnical engineering course and this course also supported by you know the work examples and some exercises which are actually done already in the slides are also going to be provided basically to show more you know interest in the subject and also to also gain you know practice and experience in solving some typical problems and these problems are actually mostly practical oriented so that and this can lead to lot of insight into the subject on advanced geotechnical engineering. Thank you very much for patient listening.


This talk will be in English, but you can also ask in German, our speaker is there flexible. So, that's the organizational one. All right. Now, we go to the talk. This talk will place in English, but you can also hear a translation if you use media CCC, then you can put the language in your browser in. The next talk is why we are addicted to lithium and how to kick the habit. Our speaker is Frank Wunderlich Pfeiffer, and he gained our about our speaker. He gained his first experience in journalism in go lamps science department in 2015. And, yeah, there, he make his first journalism experience. He studied industrial engineering. And he is an old participant of this Congress. His first stage experience he made on 32 C3 on the frighten frighten stage and on 34 C3. He also has a talk about accumulators and today he goes more special in with lithium and lithium ion battery and the history and from the history to the state of the art. So, be curious and I give over to Frank. Hello. Yeah, I had a similar talk, actually not similar. Two years ago, when we could still meet in person, I was on the stage and I had to talk about batteries. Since then, I've learned a lot more, especially about lithium ion batteries and also alternatives to lithium ion batteries, but that will be the topic of the second part of the talk. This is why we are addicted to lithium and how to kick the habit. That's the next one that will be tomorrow evening. Today, let's talk about electric cars and why I mean, you can see a couple of electric cars right here and why we need lithium to build them. At least so far and you can see, I mean, you've seen this one. This is a Babcock Electric Roadster. Babcock is more famous for building steam engines and more recently nuclear power plants, but they also build electric cars a bit over 100 years ago. And this is one of them. And as you can see, it wasn't very modern, at least not in our terms. Back then, it was among the best electric vehicles you could get. And around 1900, there was a bit of a craze of cars when they were completely new and everybody who had a lot of money wanted to have a car. And electric cars were very popular with a lot of people. In fact, about half of all cars were electric. And at least around 1900, this one was 10 years later. At that time, it was a luxury item, very clearly. And as I said, half cars were electric. Of the rest, about one quarter was a steam engine powered and another quarter was by internal combustion engines. And this changed. Electric cars were, of course, quite comfortable, at least as long as you could have somebody else maintain them. You could just sit in there and start driving slowly. 25 kilometers per hour that this one reached were quite fast for electric cars of the era. Usually, they were quite slow. Electric cars were not a fast thing at all. The range of such a car with lead-acid batteries was limited. 160 kilometers, I actually doubt if that was correct. There is a letter that was sent to the company and the company said, yes, we verify that was the case. And we are very sure that nobody recharged the car along the way. But there were no independent tests of any kind. So nobody quite knows. In any case, at the speed of 25 kilometers per hour, it was an ordeal just to get from A to B. It was very similar to the future. And at the same time, of course, other cars like the Ford Model T around 1910 were much more popular. And in later years, more than 100 times as many Ford Model T were built than the most popular electric cars. And at that time, electric cars were pretty much out. Using an electric car at the time was very difficult, much more difficult than it would be today, because there was no such thing as modern electronics. So you could have your electric car and charge it overnight, but you would wake up the next day. And if you were unlucky and you overcharged the battery, the battery would be gone. It would be destroyed. So charging the battery really required somebody to watch over the car at all times. And, well, that didn't make it very comfortable experience the way we would have it these days. It also took a long time and the energy capacity of the battery wasn't as good as it is today. Also, lifetime was very limited. These days, let's say at the end of the 20th century, you could expect about 500 charge cycles from a lead-acid battery. Back then, it was less. Nobody quite says how many, but it was fewer than that. There were other technologies available. Yeah. At the end of the 20th century, you had cars like the EV1. The EV1 also used lead-acid batteries, and you see range was about 90 kilometers. Even though at the time they said it was 126, or later they used nickel metal hydride batteries, about 228 kilometers, as they said. But the standards testing regime changed in later years, and it was by modern standards. It's about 90 to 170 kilometers. EV1 was a very expensive car. Nobody quite says how expensive exactly it was, but it seems there have been much more than $100,000 per car for the simple reason that not a lot of them were built, but 500 were built with lead-acid batteries and another 500 with the nickel metal hydride batteries. When you build something in such small numbers, it will always be extremely expensive. These days, things changed. Just compare these numbers. You have a bit more than 100 kilometers realistically, and now you have 400 or 500 kilometers by the same standards. This is the model of 2022, actually. This is Tesla Model 3 standard range plus in the newest model. I think you cannot quite buy this one yet, but new models will be delivered with that kind of range. Something changed very drastically, and that was, of course, lithium and lithium ion batteries becoming affordable, at least much less expensive than they used to be. That's not to say that the Tesla is a cheap car. It's not at all. It's like 45,000 US dollars or euros, whatever you want, and it's still not cheap. We still have a ways to go to get affordable cars. Of course, they're cheaper cars than Tesla's. But yeah, even getting here is a tremendous amount of progress, and a lot of things had to be done. One of the origins that I didn't even know that this was among the origins, but two years ago, John Goodenough got the Nobel Prize for his discovery of his help in building lithium ion batteries, and he said that this was an important step. It was inventing the sodium sulfur battery. Sodium sulfur was an important technology at the time, even though it didn't really translate into building electric cars with new battery technology. It was the first time that new battery used, didn't use hydrogen ions to go back and forth, but instead the chemistry was based in this case on sodium. The original patent said alkali sulfur battery because they hoped they could use lithium, because lithium has higher voltage and it's much lighter. And because it's much lighter, you can get much higher energy density. But it turns out that if you want to use this exact setup for lithium, you'll run into trouble because this is a high temperature battery. This runs with sodium at about 300 to 350 degrees Celsius. It's very hot because you want to have liquid sodium and liquid sulfur, and in between you have a solid ceramic through which sodium ions can go. The electrons take the other way, they go around the battery, and that's how you get the energy out of the battery. And that was invented in 1966 and people were inspired by this. They were inspired that you could use these ions, you could use alkali ions like lithium or sodium to build batteries. And yeah, just a little bit on lithium and sodium. If you look at it, it's about three times as heavy as lithium. It's bigger, it has one angstrom diameter, and the voltage direct to chemical potential is minus 2.7 volts. For lithium, essentially everything's better. It's lighter and it has more potential, so you get about 0.3 volts more in the battery. And that makes a lithium pretty much a perfect material. Except for one thing, there is not a lot of lithium on earth. I mean, there is a lot if you just count it in terms of tons, but if you look at lithium, lithium ores have about 0.1% concentration of lithium. And where as sodium you can get like 40% or something like that. The next step was to get it at room temperature and an important invention here was by Stanley Whittingham. And Stanley Whittingham was actually working on electric superconductors. And he was using tantalum sulphide, and he found out that he could change the properties of tantalum sulphide by intercalating. I mean, as you can see, there are several layers here, and you could just put some other atoms in between to change the properties of the material to get a different superconductor and maybe a better superconductor. At some point he had the idea, hey, we could use this to build a battery because the ions in these layers also chemically react with the atoms in the layer. And yeah, that was the first step. It was not a perfect material at all. The batteries that he built were in terms of energy density and not much better than lead-acid batteries, but at least they worked kind of for about five cycles. So they were not too good. But there was a guy who was good enough to build batteries. And that was John Benister, good enough. He has a brilliant name. And he was not a hero. He was just a guy who worked and he worked a lot. He was a meteorologist in World War II. In the 1950s, he was a chemist, he had become a chemist. And he was supposed to invent a ceramic that is magnetic and could store information for the computers that were just coming up in the 50s. And he invented the ferrite course that you might have heard of and at least the material for the ferrite course. And then for the next 10 years, he was doing research in the lab on properties of ceramics, especially electrical and magnetic properties of ceramics. And that helped him later on, though not at the time. He was just doing fundamental research.  His university wasn't funding him anymore. And so he was forced to go into industry. And he said he was forced to do it, but it was not a bad idea. And he had the idea that instead of titanium disulfide, which was Whittingham was using, he could use something else, namely cobalt oxide. He was doing a lot of work with oxides and cobalt oxide was one of them. And you can see that titanium sulfide, because of the sulfur, is quite heavy, actually. And titanium is not a perfect material to react with lithium. And so what you get is a voltage of about 1.8 volts for the battery. And he said, okay, let's use cobalt. And he knew how to get the right structures out of material. He knew the correct reaction conditions and everything because he had worked for 10 years on that sort of stuff. And so he could create a cobalt oxide that was built up in layers and you could put the lithium into the layers where they could react with the cobalt. And that way he could build lithium ion battery. That was much better. It had more voltage. I think 3.8 is bit too low. It's 3.9. And the material has low mass and that way you could get a much higher energy density from it. You also needed a much smaller anode because the amount of energy you get out of one lithium atom depends on the voltage. And when you have lower voltage, when you have half the voltage, that means you need twice as many lithium atoms to get the same amount of energy. And yeah, so you need anodes. The problem with anodes is, and Whittingham didn't have a good anode. That's why his batteries only lasted for five cycles. That changed with Rachid Yatzami. I hope that name is correct. He is from Morocco and I don't speak the Berber language. I'm sorry. He thought, hey, we could use graphite. And in graphite you can put lithium ions in between layers. Because, I mean, that was the top, that was the view from the top. And you can see graphite is built up of layers just like cobalt oxide. And in between these layers, you get the lithium ions. And I'm sorry, I didn't have enough time to animate it like here and just put them in between the layers. But you can imagine how that works. Every lithium ion needs six carbon atoms to be stored. And that is quite heavy. The carbon weighs about 10 times as much as the lithium. So that is kind of limiting, but it's still very good. And you can do it thousands of times without destroying the graphite. The important step here was actually to find an electrolyte where the ions could move in. So the ions could move in it, but the electrolyte wouldn't get between the layers and destroy the graphite. And something similar was also needed for all the other layered materials. And eventually that was found and it worked out. And yeah, these days things have changed. Cobalt, lithium cobalt oxide is no longer the main material for a long time it was and it was very important. The problem is the cobalt is a very rare material and you have all heard about how it is mined. And so people want to get away from it. But primary motivation was not getting away from cobalt mines in Congo. The primary motivation was to get better batteries. And the batteries that they had was you could exchange the cobalt for nickel. And NMC materials is nickel manganese cobalt. And the idea is to get as much nickel inside the battery as you can. Without getting the nickel, I mean if you have nickel, if you have only nickel the problem is that the nickel has about the same diameter as the lithium atoms and it gets into the layer where the lithium is supposed to be. And you don't want that. And so you need manganese and cobalt to stabilize the entire structure. Eventually that worked out. It was a bit of a challenge to make that work. But it worked out and about 20 years ago people started to figure out how to make such materials. And NMC 111 was the first. The numbers just say how much nickel manganese and cobalt is. So 111 means it's equal parts. 811 means it's eight parts nickel, one part manganese, one part cobalt. And you see it's just making everything better. The problem with cobalt is that you cannot get all the lithium out. And with NMC 811 there's essentially per gram of the material there's the same amount of lithium but you can get much more of the lithium out and that's why you have a higher energy density. It really seems to make everything better. You get more energy from a cheaper material and it's more compact. It's just almost everything is better except it's not as resistant to heat. When you heat it up it tends to release the oxygen. I mean it's an oxide so there's oxygen in there and it releases oxygen and unfortunately it's inside of an environment with an electrolyte that is a hydrocarbon and hydrocarbons burn. And when you release oxygen into hydrocarbons it starts to burn and they start to heat up the battery. And now you have a hot battery in confined space and you have it in an electric car the entire car can start to burn and sometimes that has happened. And so you need to put a lot of effort into making sure that there's always enough coolant and that if one battery heats up it doesn't heat up other batteries that will start heating up themselves and so on. That is a major problem. Regardless, what we have seen in the last 10 years is that we can build batteries much cheaper. One of the main reasons was building much bigger factories. It's the same as with the early electric vehicles or the EV1 where we only built like a few hundreds of them. And the small number of batteries or the small number of cars means that each car or each battery was very expensive. If you go on YouTube and you look for videos from battery factories in around 2010 or so or 2011 you will see a lot of hand manual labor being done. I mean, every battery in those factories got touched by people and manipulated multiple times. It's very slow, it's very expensive and that's why prices were extraordinarily high. You paid over $1,000 for a kilowatt hour and now it's about $130 per kilowatt hour in the battery pack. But you can get below that, you can get below $100 if you use different materials because things have changed. The factories have become much more efficient, much bigger, much more efficient, production is much cheaper and the cheaper production means that now these days materials start playing a role. It used to be the case for a very long time that the price of lithium had no bearing on the cost of a battery or the cost of cobalt. It didn't matter. I mean, when you pay $1,000 just to make the battery who cares if your cobalt costs $10 more or less? Nobody cares. When your battery costs about $100 or so, you care a lot whether something inside the battery suddenly costs $10 more or less or $20 or $30. And that has changed. And these days, as you can see at the end of the graph, at the end of the graph I put lithium iron phosphate batteries for comparison and they were much cheaper. You can get at least 10 kilowatt hours for $1,000 in a battery pack. On sale level it's even cheaper. And that is because there is no nickel in there. There's no manganese in there. There is no cobalt in there. The mining companies hate it. They absolutely hate it. But the battery companies, of course, they like it a lot because it's much cheaper and you can offer a battery that can drive a car for a much more reasonable price. We can see this here on the graph actually because LFP is much more resistant to heat. You can build a much lighter. You don't need as much weight and structures to keep the batteries cool and to keep them safe. And that way, even though the battery cells with NMC811 have much higher energy density, the battery pack can be almost the same. The energy density of the battery pack can be almost the same simply because you can save so much weight. Chinese companies like BYD and CATL have built the blade batteries or cell to pack technologies. And those have resulted in a revolution. This year is the first year that LFP batteries is more than 50% of the total production. And it was really funny. Earlier this year, I heard an analyst from Bloomberg talk about LFP and he said, it's a mirage, this will just disappear. And yeah, in industry, there are a lot of people who essentially deny the existence of alternatives to rare materials, especially those who invest in those rare materials and stand to benefit a lot from high prices, especially from high prices and mining. We will see that change. And the same is true for lithium as well. You can avoid using lithium in batteries. And I've talked about this two years ago, that this is possible. Two years ago, I didn't know just how far the technology had progressed. I have read a lot about sodium ion batteries since then, and this will be a topic of the talk tomorrow. But for now, we can have a look at the markets and we will see that in a matter of 12 months from November 2020 to November 2021, the price of lithium has risen fivefold. It went from the lowest price that we have ever seen for lithium, or at least for a very long time, to the highest price that we definitely have ever seen. I mean, lithium has never been more expensive than today. And this is not going to stop because right now all manufacturers of cars, especially cars, start building batteries or want to buy batteries. Some of them started building their own battery factories, especially Tesla, but also others. And they didn't look where they would get their lithium from and they didn't invest in lithium mining or anything. And the big problem is you cannot just say, you cannot snap your fingers and get lithium out of the ground. It takes a long time to build the mining equipment and build up the mines so you can start mining because, I mean, you're taking dirt from the ground and then you start to invent, for each mine, you have to essentially start inventing your own process how to get clean lithium out of the dirt you've gotten out of there because that dirt you're digging out is, or stones or whatever, is mostly not lithium and you have to really get all the impurities out. And this is a very difficult process and depending on where it is, it takes five to ten years to get it right. And something similar, I mean, that's why right now we're really locked into whatever investments have been made five years ago also. And nobody quite predicted how much more demand there would be for the lithium-ion batteries. And yeah, if you want to make many more batteries than the investment allows five years ago, then you have to go look for something else, something that is not there to you. Something similar happened with nickel, but changing from NMC to lithium-ion batteries to LFP to lithium-ion phosphate really prevented that from happening. I mean, nickel is more expensive but just by 26% or so. So there will be no fast battery growth without further substitution because you cannot build lithium-ion batteries without lithium. And yeah. Yeah. Thank you. If you want to know where the 16-color pictures came from originally, where they were converted from, I can absolutely recommend Hawkins Electric Ride. You can find it on archive.org. It was published in 1914, so this should be a public domain everywhere. And I can absolutely recommend reading this how electric cars work back then. Any question, please? And if you don't want to ask in English, that's fine. Just ask in German. If you need an answer in German, please just say so. Okay. So thank you very much for this interesting talk. And first of all, if you're curious, tomorrow there is part two of this talk. And there you can see the part how we can get rid of that problem of our addiction to lithium. I'm surely there. I'm very interested. And now we have questions. First question question is, how big is the impact of lithium prices in the context of the general electronic shortage? Okay. The lithium price used to be on the order of about four to five US dollars per kilowatt hour. That was last year. This year it's more like $20 or something like that. And when you look at the cheaper end of the batteries, which is on the cell level, that is when you have a battery, you first have to have the actual battery cell, and then you have to take your battery cell and build big battery packs so you can put it into your car. Those are more expensive, but on the cell level, the individual cells, the cheapest cost something like 60 or 70 US dollars per kilowatt hour is something on that order. And when you have to add like 15 or 20 US dollars to this kind of price, that's quite a lot. It's not just lithium that got more expensive, also some other components of the battery, but this is certainly most prominent. And most of the price increases hasn't really gotten through yet. The price that is referred to there is really the spot market. So if you just want to go and buy a thousand tons of lithium or whatever or lithium carbonate, that's one thing, but most of the lithium is bought in fixed contracts and the new contracts are not yet negotiated. So these contracts will be made like in the next few weeks, next few weeks or months, and they will demand much higher prices than they used to. And that's when the actual price will come through and everybody expecting something like 20%, or something like that more than it used to be. And this is very strange because in the last 20 years, batteries have essentially almost always gotten cheaper every single year. And this is not the case right now. This is the first time that battery prices are on trajectory to start getting more expensive again. Next question is, what can we as the end user do to make it a little better except for the regular things like recycling? Recycling right now actually doesn't matter to much.  They last a really long time. I mean, thousands of cycles. You can actually see that the batteries will last longer than the cost themselves. So with electric cars recycling is actually, for many years to come, recycling will not be very important to alleviate any lithium or raw material shortage. This will take a lot more time until those batteries are actually finished. Right now it's done by SUVs because SUVs need much bigger batteries because they are not aerodynamics. I mean, it's a giant brick that you have to move through the air and it requires a lot of energy to get the air away. So if you buy smaller, more aerodynamic cars, they will automatically need much less energy to move forward. So that helps. In general, smaller batteries, the less battery, the less lithium. That's always the same. And I mean, it's not like we will have less lithium in the next couple of years. That's not a problem. We will always get more and more lithium in the coming years. It's just the demand, the amount of lithium that is needed by the factories and by the companies. That is rising much faster than the amount of lithium that the mining companies can provide. So there's a gap that is growing. The only thing you can do is to push for alternatives to lithium because the mining companies physically cannot provide enough lithium for the next coming years. We have two questions left. One from Northern Portugal. I'm currently in Northern Portugal, where one of potential European mining areas are located. I sense a strong opposite with the locals. How realistic is the hypothesis that there is no need to extract lithium here? In general, it's a problem to say. I mean, there is a not in my backyard problem here. Because you can always say, yeah, we need lithium, but not from here. And one of the reasons I did this talk in two parts was to say that lithium ion factories are actually important. In some applications, you absolutely need the maximum amount of energy density, and lithium is the thing that provides that. So we kind of do need lithium. That is not a question from where exactly is indeed a good question. Whether it's from Portugal or not, I cannot really say that, because I haven't actually looked at the exact circumstances of the mining area in Portugal. But you should definitely have a look at making impact as small as possible in terms of what is population density, what are local resources, what's the environment like and so on. And you really have to compare that. But you have to get it from somewhere. And you cannot just go around the world and say, but not from here everywhere. And as I said, I'm not saying Portugal is definitely, you definitely need to go mining in Portugal. I absolutely, that's not what I mean. Just have a look at this exact situation there. And if you want to argue against it, then you should provide an argument that there is a good reason not to mine here, but maybe elsewhere. In the short run, we absolutely need it. And we need sodium in addition to that. Okay, we have some new question. And this is one of the two. Do you know of any alternatives to the 18,650 batteries that can handle two A current troughs? If I knew the capacity of, if I knew the typical capacity of an 1865 battery, then I could answer that question more easily. But I don't have it on top of my head. So if you had given me a C-rate, then maybe it really depends. If you need high power, like just if the amount of energy in the battery is not quite so important. So if you could do with, let's say, half the amount of energy inside the cell, then of course there is, you just need high power for a short time. Then of course there's an alternative, the combination of high power and high energy. That's a bit more difficult. Yeah, we're running short on time unfortunately. I think there's time for one more question. Otherwise, I think there's an overflow room somewhere. Maybe you can go ask the question there. Yeah, one question. We have a short one. What, Christ, does point mining from seawater will become an opinion option? Right now, right now no price because nobody has really developed a process that is economically feasible and also scalable. As soon as that happens, you have to look at the price they offer and then you can do the math. I'm sorry, but I can only report on what has already been done and anything else is speculation and I don't know enough about the field to do speculation based on any good data.  Short question, short answer. Very, very thank you. I hope you have as much fun as I had and I'm very curious of your part two and if your question couldn't ask today, come in tomorrow, look at the part two. One more thing, very quickly. I know that the font is not very readable. I use Pico8 to do this presentation because I just liked it. I like the aesthetics of it, but I will use a more regular presentation tomorrow because I've been told that it's not very readable, so if you find it not too readable, then come back tomorrow will be easier. Then again, thank you and see you tomorrow. See you.


o personal, or I'll just drop you guys the link to the break schedule for Forrest, there you go. All right, guys, thanks again for hanging out tonight. Hope you have a great rest of your night, and I will see you guys in about 10 hours.


What's up everyone takedown here welcome back to another video as you guys know I am an eBay reseller and today I'm gonna be showing you and taking a closer look at My eBay room. Sorry for the mess, but let's get right into this So here we are here is the eBay room And we're just gonna start over here with this TV stand. So a lot of my products are An inventory is scattered around so some of them is up here along with I guess tape that I forgot Down here. I have my huge 175 foot roll of bubble wrap that I use I get it pretty cheap along with my tapes scissors, and if I have to leave a little note In any of my packages This here is handy for Canadian resellers. This is the slot of doom this as long as it fits in here the oversized letter mail I can ship a video game for three dollars and nineteen cents anywhere in Canada Without tracking with tracking if it's an expensive game, it's around fourteen dollars. I Do have other stuff in these totes here in the first one It is mostly plushies that I bought a while ago a bockman a lot I haven't really been selling many of them, but I don't have them all listed right now underneath that There is some books and other stuff But this tote is mostly plushies Over here. We have a little bit of everything. We have Some hockey cards in the boxes over on the right. I have some of my shipping materials So I have some leftover bubble wrap and flyers to put as packing material Markers my labels and a little bit of everything including some products I do have my books in here that I got at thrift stores and a few things on the bottom as well along with a lot of tape and over here is the hundred pack of Poly bubble mailers that I use for my for my video games I think I was around thirty dollars and then just in the corner here is just a bunch of boxes that I have for whenever I sell some of my consoles Over here in here. I have three of my consoles my ps3's and The Xbox up here is when I got it from a thrift store Doesn't really work hard drives missing Some other things that I can't test right now. There was no controller with it So this was about twenty five dollars. So at the end of the day, it might be a twenty five dollar loss But there's profit in here a couple great consoles in here Over here is where I have all of my video games stored. I Do have some more in the other room But most of them are ps3 from the ps3 video game lots that I purchased But there is some Xbox and sealed games as well. I just sold a 3ds Pokemon game That was the last one from a lot that I did have And then up here. I do have an Xbox 360e This one here the only issue with it. I paid twenty five dollars for it The only issue is it came from a smokers house So inside it smells like smoke. So what I'm gonna do is try to get the smoke out. It's been sitting for about a month It's still kind of smells like smoke If I get the cigarette smoke out, I'm hoping to get around 150 to 200 for it But at the end of the day, it's twenty five dollars So if I can't get it back to working condition, then I'm just gonna have to just toss it and get rid of it This is the most items that I have in here is just what you see in the other room I do have a PlayStation 3 that's unlisted and a couple other things that are unlisted But for the most part, this is all of my inventory right now So hope you guys enjoyed this quick little eBay room tour again. It's nothing great I'm still doing this kind of part-time right now since I'm not working at the moments I am trying to do this full-time and I do have a lot of consoles that will sell for great profits There's a lot of profit in my inventory that is gonna be pretty decent profits when it does sell It's just a matter of making sure everything is listed and all the shipping and everything is right That way I have no mistakes and no possible returns if I have everything done correctly Thankfully, I've been selling a lot more since November 2020, but recently I've been pushing a lot more as well anywhere between Five to maybe ten sales per week on average and mostly that's individual video games Which I do list individually some of them are on auction and range between five dollars profit to fifteen dollars profit Some are around thirty dollars profit depending on the video games and the video game lot that I did purchase it from so Pretty decent profit I've been making but I just wanted to show you my eBay room. Yes It does look messy, but I know where everything is all the inventory. I do have listed on eBay I know exactly where it is and all my shipping materials. I know where my poly mailers are I know where my markers my address labels. I know where everything is and that in my opinion is what matters the most so I did tell you previously and I think my YouTube setup video that I was gonna show you guys my eBay room. I finally have done that It's nothing amazing. I've seen other people where they have garage with shelves and everything is labeled and there's Containers where it says ABC and on their eBay listings. They have it appropriate so they know exactly where to find everything I'm not at that level yet. I know I do have a lot of inventory Not thousands. I have maybe a hundred inventory Hundred different listings, but I'm growing still and I'm still making some decent profit So hope you guys enjoyed this video. I'm gonna leave this here Please take care if you guys want to look into some of my other eBay videos I am gonna be doing them a little bit more frequently now that I'm getting back into it and Sharing a lot of my stuff with you guys as well. So I'll see you guys in the next one. Please take care. Peace


It's extremely difficult to deal with anybody in our life who is making suicidal threats and something's been going on between Keemstar and Boogie2988 and we need to talk about it and it's a very serious subject and a little bit of a trigger warning obviously we're going to be talking about some sensitive stuff so if you need to take off, I'll see you next time. What's up everybody? This is Chris from the Rewired Soul where we talk about the problem, but focus on the solution. If you're new to my channel, my channel is all about mental health. Sometimes what I do is take what's going on in the YouTube community, try to see what we can learn from it because a lot of this stuff is happening in our own lives. So if you're into that stuff make sure you subscribe and ring that notification bell and if you didn't know all this month I've been writing a crap ton of mental health blogs over on the RewiredSoul.com, my website so if you want to go check that out and then after I'm done after I wrap this up I'm actually going to put it all together in a free ebook that I'll send out to everybody. I'm going to record an audio book as well but I got to pay an editor and all that stuff so that one will cost probably like five or ten bucks but anyways I'll keep you posted but for right now go check out the mental health blog if there's different things you want to learn about improving your mental health.