 Now, the question is if you want to study the long term interaction what should be done because this loading is going to be short term instantaneous most of the time. So, if you are interested in long term interaction you have to talk about different energy fields and these energy fields would be thermal energy field, electrical energy field, magnetic energy field and radiation energy field. Is this part clear? No, you do not agree express yourself, ok then you hold on for some time. So, let us start with the mechanical energy field. So, as we said that mechanical energy consists of two things that is the position potential energy and kinetic energy which is the motion. So, any potential energy will be stored in a physical system is this ok and this can be released or converted in other forms say kinetic energy. A simple thing which you are doing right now is when you load the soil mass if it is saturated water comes out and particles compress. So, potential energy has got converted into two components. So, if you say P e on the left hand side is equal to kinetic energy plus P e 2 where P e is of the different grains and their reorientation and their spacing between the two fields. And kinetic energy is the amount of water which comes out in the form of some velocity component and the movement of the particles types of potential energy. So, each one is associated with the particular kind of force. Elastic force is nothing but elastic potential energy. How would you compute energy associated with a phenomena when you plot load deformation graph? Can you compute the energy or the work done on the system or by the system? You integrate the graph on the x axis is it not. So, work done will be nothing but force multiplied by displacement d x. So, f d x integration of this will give you the energy which is stored in the system. It is nothing but elastic force as long as you are working in the elastic region. Gravitational force which is nothing but the gravitational energy the location of the point or the position of the point with respect to each other. Coulomb force is nothing but electrical potential energy. The energy stored between the two charges and of course the nuclear force which is nothing but the nuclear potential energy. So, present is geomechanics and the people what they are trying to do is they are trying to tap these concepts of energy in redefining the concepts associated with all mechanisms which take place in soil mass. I have given you examples of two because right now only two things come to my mind that is the compaction and consolidation theories which can be rectified very easily. If you do these tests in a very controlled environment forget about the sound and light energies other things can be controlled you can measure the temperatures and velocities and what not. So, basically if you try to focus on what are the components of the potential energy. The first one is compaction process which is governed by the potential energy. What happens densification? So, initial sample which was of certain volume gets reduced the sample size gets reduced. Consolidation is this correct? Rearrangement of the grains rearrangement of some new structure of the soil mass. Distortion of the grains I have talked about either because of bending or crushing or because of rolling. So, this is bending crushing. Needing is a sort of a compaction where again the potential energy goes and sets into the grains and grains get reoriented. Shearing is also a sort of a potential energy of this link with the phenomena which is dynamic phenomena. When you are shearing two materials. So, there is a movement here, but then the rearrangement of the grains because of shearing process is nothing, but because of the PE getting stored into the system. How about the kinetic energy? Movement of water through porous media either through consolidation or because of seepage. Excessive pore pressure generation vibrations. So, you vibrate the system it is nothing, but a process which is related to kinetic energy. So, as you can notice that present day scenario is people are trying to put things together. Look look at model is there right now, but definitely these are the foundation stones for developing new models based on which the new classical models will be proposed in the days to come. So, blasting operation how do you define this process? It is a chemical energy which is stored in the blast alright and it gets converted into a mechanical energy. And this mechanical energy results in densification of the soil and movement of shear and compression waves in the medium. Go one step ahead. The shear waves and compression waves they are creating a different state of the material and densifying them. So, this is the concept which we use in temple of sandy layers or modification of sampling sandy layers by using vibrate flotation or by heavy compaction. So, shock waves have to pass through the porous media. So, that becomes densified. Is this part clear? So, there is enough examples which convinces us that yes these components should be studied in details. Now, let us talk about the mechanical energy field. Basically these are all short term processes. When we say short term, short term with respect to the life of the structure which is going to be is it not? And they remove the influence of the environment particularly decay alteration of the material in the due course of time. No mechanical loading can simulate this. In centrifuge what we are doing? In centrifuge you are utilizing the mechanical energy in the form of accelerated gravity. So, this is also a form of mechanical loading on the system and that is the reason you cannot simulate any biochemical process which may occur otherwise in nature in this centrifuge. There is a limitation is it not? Now, load deformation, velocity, weight, mass, wave, sound all these phenomena they are associated with mechanical energy field. But this point is very important. When we model our system with the help of using mechanical energy field concepts, we are not talking about the influence in the long run. Where do we use these concepts of load deformation velocity, weight, mass, wave, sound? Foundation design, load deformation characteristic, bearing capacity, bearing pressures, flow through porous media velocity comes into the picture through a control mass or volume. Acid drains, the influence of acid drains on the foundation structures creation of whites and so on. Toxic hazardous waste, nuclear waste storage and containment. Again you are talking about the migration of the contaminants from contaminated site to uncontaminated sites, landslides. It is a good example of how potential energy and kinetic energy can interchange itself several times. So, landslide takes place because of excessive potential energy when the soil mass of the rock mass falls down, it attains kinetic energy. Again it defragments all those defragmented materials they will again start moving, rolling down, sliding down and again they will achieve some stable position and so on. And of course, earthquakes where the waves and sounds and the mass and the velocity comes into the picture. So, this is what the scenario right now. We are able to tackle all these problems associated in geomechanical engineering profession with the help of simple mechanical engineering, mechanical energy field theory is it not? They are exposed to loading processes and we are more interested in finding out the deformation. The second question is if you want to model these things, what are the laws which are associated with this? So, you use Darcy's law, Hooke's law, Newton's law and law of motion. Particularly those of you who might be working in landslides, they will be using a lot Newton's law of motion and laws of motion basically. Continent transport seepage through chorus media and all Darcy's law. And load deformation characteristics we talk about Hooke's law. So, the basic law of mechanics are these four which we are utilizing in characterizing the chorus media or the geomaterials based on mechanical energy concept. The second important energy field which is gaining attention of everybody's particularly researchers is the thermal energy field. And fortunately this energy field includes the effect of environment. Any interaction process will cause heat to generate. A good example is you add soil and water together. There must be some heat of hydration of soil, is it not? Thermal cracking and so on. So, hydration is the word which is associated with this type of process. We call it as heat of hydration. The amount of heat which is liberated because of addition of water to a soil mass or a geomaterial. We talk about heat of wetting. Have you heard of this heat of wetting? Heat of contact and heat of sublimation, thermo osmosis, anyway these are applications. Actually heat of wetting and heat of contact are the terms which I am trying to coin and I am trying to develop some models based on these two terms. Any guess what heat of wetting would be? That is that is hydration that is right. So, there is some difference between hydration and heat of wetting and heat of contact. See truly speaking this should have been put in a reverse order. The first material comes in contact with something, whatever amount of heat gets generated. Later on the wetting process starts which is a surfacial phenomena and ultimately everything enters and penetrates into the matrix of the material where the hydration starts. So, most of the time you will notice though we call it as hydration process. If you want to define the interaction of geomaterial with environment, the first thing is the material comes in contact with something and what is that happening at that moment should be captured. And the second thing is what amount of energy is required to wet the system completely and of course then comes your hydration process. So, it is a very good concept on which one of my PLG scholars will work which is known as that is geomaterial contaminant interaction. So, the first question which comes to my mind is how do you define this interaction and I get motivated while coining these terms you know by our colleagues in construction materials those always define heat of hydration of cement. So, if you want to find out the activity of a material please note these words and correct me if you do not agree. The way we define activity in geomechanics is not a very correct way because if you want to define the activity of a mineral the best way would be to give it enough chance to interact with water or contaminant and find out how much amount of energy is getting liberated out of it. So, that will be the perfect interaction. So, that means if you just want to you know phase at the point of interaction what is happening to the system these terms are of great use that is heat of wetting heat of contact. We will talk about heat of sublimation in the subsequent slides thermo osmosis is a phenomenon where we in which you apply some heating osmotic pressures increase water oozes out and the system stabilizes. Some of the practical real life problems would be freeze throw process if you want to model freezing and fine of the geomaterials wetting drying cycles. I think this is the topic which I have floated also for my entire students and I do not know if I am correct I think I have floated this topic wetting and drying cycle. The whole idea of studying this type of cycles is that what really happens to the system in case they come in contact with water and then the environmental conditions become such that that they have to expel water from them. So, this is sort of a annealing process which a metal goes through when the casting is done. So, this will show you the vulnerability of the material towards environmental degradation and of course fires and mines in the underground environment is a famous example of how these studies are becoming so important particularly methane catches fire when you do mining and thermal and desiccation cracks which are formed because of excessive heating of the soil mass. So, the question is what are the laws which we are going to use for doing these type of studies all right. So, v equal to k into i is nothing but a mechanical law Darcy's law where you are using two mechanical energies equating them with each other. Now, here when we talk about thermal energy fuel the governing laws would be gas law p v equal to n r t Fourier's law of heating and cooling and laws of thermodynamics where you must have studied this Carnot cycles Carnot's engines. So, I think these concepts can be utilized in finding out the thermal equilibrium between the soils and the water and the soil and the contaminants and so on. I hope you will agree that this is required to be studied by people in the long run is it not. What are the basic characteristics of thermal energy field? So, this is very interesting I am sure you might have experienced also there will be some additional force which get developed because of you know thermal energy field exposition to the particles or the soil mass. So, additional force are produced when water is added to dry or partially such as soils clear. You must have seen when you boil milk there is a skim formation and that skim is a very dynamic process. So, that the entire membrane keeps on showing lot of tension developing into the system. The same thing is happening in the form of surface tension on the soils also when you do shrinkage limit as cracking and all. So, this basically it indicates that because of the thermal flux the soil mass becomes very dynamic system and that dynamic system has to be studied to quantify what are the forces particularly in terms of thermal stresses which are getting generated into the soil mass. So, heat transfer due to thermal field which may affect soil water air behavior because the common sense is there will be a dilation or volumetric expansion of all the three phases of the soil mass because of thermal field exposition. I will be talking about these bases when I will touch upon the thermal properties and thermal characterization of the geomaterials in subsequent lectures. So, state of matter which is existing the thermal energy field will be changing due to the temperatures which are implied on this. The first phase is that look would we get transmitted into or transformed into the gaseous stage because of heating. So, it is nothing but the heat of vaporization. So, if you can find out the heat of vaporization of a material when it interacts with water or when it interacts with some contaminants I can quantify this interaction you agree with this. So, that means heat of vaporization will be a good quantification of interaction between geomaterials and environment. The second is liquid to solid transformation what is this known as heat of fusion. So, people who are in atomic industry they are using this concept quite a lot they amalgamate the entire waste under in-situ conditions it is a fusion process which is going on all right. And third one is solid to gases and solid to gases known as heat of sublimation. So, there could be a situation where the entire waste can be sublime into a gaseous form clear and these gases can be used for some other specific industrial applications. So, basically this already depend upon the type of energy input or the release which is coming out of system. So, when you say energy input and release it becomes a reversible process. If I put the heat into the system it melts if I take out the heat from the system it freezes clear. So, that means when I say liquid to gaseous and gas to liquid system it is just whether you are taking the energy from the system or you are inputting the energy into the system compressed air if you compress it much more what happened it liquefies ok. So, liquefaction basically gives you low temperatures. So, you can do air conditioning by this process. We will quickly cover electrical energy field which includes the influence of the environment as such most of the minerals which you have in the soil they are magnetic minerals and hence they will create electric field. So, when you talk about polarization electromotive force electrical conductivity this type of energy field become quite important. So, particularly those who are studying creep viscosity stress hardening and softening aging effect of sands contaminant migration you might have seen we are using this concept site remediation particularly electro kinetics and electro osmotic process where you can use electrical energy field to decontaminate the soil mass by applying different type of electrodes and you can create a situation where all the contaminants may get collected into some zones. What are the laws you will be using for these type of modeling the Coulomb's law Joules law Ohm's law and Ampere's law. So, with the help of these laws you can deal with electrical energy fields and its implication in geotechnical engineering then comes your magnetic energy field. Of course, this is the reducing order of the intensity of the effect. So, the most important effect is mechanical engineering followed by the thermo energy field followed by electrical energy field followed by magnetic energy field where again it may include the influence of environment particularly if your minerals are magnetic in nature. So, we talk about electromagnetic effects ferromagnetic effects induction electromagnetic waves which pass through the soil mass based on these concepts we are using time domain refractometry and frequency domain refractometry probes. And the basic idea of using these probes is that you want to characterize the soil mass for determining its volumetric moisture content. What are the laws which you will be using for modeling these type of situations? Faraday's law Lenge's law Biosybert law Gauss law alright. And what are the applications of electromagnetic field in various disciplines? We have X-rays which are nothing but electromagnetic waves of different high radiations. You use them in radio astronomy, radiography, medicine, telecommunication. Laser therapy is very useful which is a example of photo medicine. And application of laser beams is basically in guided bombs, barcode readers and laser therapy. Well radiation energy field does not have much of influence and though it also includes the influence of environment basically it talks about decay, radioactivity and nuclear reaction. This field is less exposed and explored till now and the governing law should come from the nuclear physics and atomic physics. So, ultimately having studied all this what is that we are trying to do? This is what actually we are trying to end up. I hope you will appreciate that we talked about the environment which is natural and manmade where we have mechanical energy field, electrical, thermal, magnetic and radiation. Ultimately what we want to do is we want to study how these energy fields can be used in the best possible way to understand the response of geomaterials. So, suppose you consider mechanical energy and electrical energy. So, there is nothing but a coupling phenomena which is known as electro viscous effects. So, those of you who are working in claim immunology they use electro viscous effects to find out the double layer diffuse layer concepts and so on. If you put these two together electrical energy field and thermal energy field it becomes electro thermoelectric effects. So, you can use one cause and one effect to see how thermal energy and electrical energy are getting influenced with each other. Electrical energy, magnetic energy field is nothing but a electromagnetic process which are being used quite a lot in geotechnical engineering and geology these days. And magnetic energy field and radiation energy field will form electromagnetic radiations in which people are quite interested these days particularly in designing the atomic shelters during the war. This is where I will stop today. I have given you a lot of ideas about where the geomechanics should head to in the days to come and what is the role of people like us in developing this subject in a more realistic manner.