So good morning Maker Faire. Thank you for coming early and kicking it off with Beginner's Guide to Quantum Computing. I'm Talia Grishan. I'm a research scientist at IBM at the New York office. And I'm actually a beginner myself. I just started learning about this six months ago. So I'm here to tell you that anyone can get started learning about quantum computing. And hopefully after learning a little bit about it this morning, you'll be motivated to learn a little bit more. So I want to start with two facts. Fact number one, classical computers have enabled amazing things. The internet, they're part of how I got here. I was able to fly across the country on a plane. The electronic giraffe outside, blaring music. Classical computers have enabled just amazing things. But one of the things we don't often talk about is all the things they can't do. We talk about all the stuff they can do. There's so many things they can't. So I want to start with two examples of things classical computers are really bad at. And maybe they can solve small versions of these types of problems.  So the first example is optimization. Optimization is I want to find the best solution to a problem among many possible solutions. So here's a picture of a table. This is the table at my wedding. It's one of many tables. But you can see 10 people around a table. You have 10 people over for dinner. How many different ways are there to configure 10 people around a table? The answer is 10 factorial. The number 10 seems so small. But 10 factorial is 3.6 million. There's 3.6 million ways to arrange 10 people for dinner. Next time you guys have dinner with 10 friends, share that fun fact with them. So when we go and do this, we consider some of the options. We make approximations, because it's the only way we're really going to end up seating people at all. But the truth of the matter is, every time I add one person to my dinner table, the number of possible configurations grows exponentially. So we can solve small versions of this problem on classical machines, but we don't solve big problems, big versions of this problem very well at all. Second example is chemistry. This is a picture of an nitrogenase enzyme. Anyone who's ever eaten food should care about this enzyme. It's an important catalyst for the creation of ammonia, which is an important component of food fertilizer, pharmaceuticals, and many other things. So this is the enzyme. I've called out three molecules, iron sulfide clusters in this enzyme of different sizes. The one on the left is four iron atoms and four sulfur atoms. Believe it or not, this is the biggest of those iron sulfide clusters we can simulate on the biggest supercomputer that we have. It's so small. Why is that the biggest molecule of these three that we can actually simulate on a classical machine? And the reason is because to actually simulate what's going on in that molecule, I have to account for every electron-electron repulsion and every attraction of the electron to the nuclei. And that number grows exponentially, the bigger the molecule. Every single electron exerts an electrostatic force on every single other electron. So when I add another one, I got to recalculate all the electron energies. So these two bigger clusters, they look so small. We can't simulate them. So there's actually many problems that have this characteristic. And what they have in common is this idea of exponential scaling. So there's a classic fable about the power of an exponential. And the fable goes, the creator of the game of chess brought the chessboard to the emperor and the emperor said, I love this game. What can I give you as a reward? And the craftsman said, okay, there's 64 squares on the chessboard. On day one, give me one grain of rice. And every day after that, double the number of grains of rice I get. So on the first day, the emperor gives him one grain of rice. The next day two, the next day four, the next day eight.  But after a month, he had the rice production of a small country. And after the full 64 squares, it was Mount Everest of rice. So it grows really fast. The number 64 doesn't sound that big, but two to the 64 is an enormous number. So why do we think quantum computing is actually gonna allow us to solve some of these problems? We can't solve classically, right? So it boils down to two fundamentally quantum effects. One of the effects is superposition. So classical information is basically a string of zeros and ones. Everything that classical computing has enabled is boiled down to a sequence of zeros and ones. So quantum computing or quantum information has this property that the states can exist in a superposition of zero and one. So not just zero, not just one, but a superposition of zero and one. And you can also have complex superpositions of zero and one. So you start to be able to explore much richer set of states. So if one qubit can be in a superposition of two states, then two qubits can be in a superposition of four states. And three qubits can be in a superposition of eight states. So the possibility space you can explore is much more interesting and complex in quantum information. So the diagram on the right is showing you a superposition of five qubits, right? So you can be in a superposition of 32 states. So superposition is the first thing. The second thing is entanglement. This idea of entanglement is, okay, I've got two qubits and I'm entangling them together. So measuring the first qubit can tell me something about what will happen when I measure the second qubit. So entanglement is the second property that gives quantum information a really unique difference. So together, this allows us to totally change how we run algorithms, right? So take the optimization case. If I'm gonna consider 3.6 million possible ways of configuring 10 people at a table, classically I have to consider each one individually and then I have to compare them all, right? Here's how quantum computing is gonna solve that problem. You take your qubits, you go into a superposition of all the possible states, all the possible configurations, and then when you encode the problem into your quantum computer, you're applying a phase on each of the states. The phase is that kind of axis towards the center of that sphere you saw in the previous chart. You encode a phase on each of the states and when waves are in phase, the amplitudes add and when waves are out of phase, they cancel, right? So when you have noise canceling headphones, what you're doing is you're creating noise that's exactly out of phase with the noise you're trying to cancel, right? So in quantum computing, you're gonna go into a superposition of all these states. When you encode the problem onto the machine, you're applying a phase on each of the states and then you're using interference and you amplify some answers and you cancel other answers, eventually you arrive at the solution. So it's just totally different, right? You just gotta completely rethink how we're gonna solve these problems and that's kind of how quantum's gonna do it. So it's obvious why the number of qubits matter, right? If I have one qubit, I can be in two states and the more qubits I can have, I can be in a superposition of two to the n states. But another important factor is this error rate, right? I have to be able to control what's going on in the qubits. If I have really high errors and all of my operations don't work out as I expect them to, then that's not gonna really work. So we're promoting a new metric called quantum volume where we're saying, okay, if you increase the number of qubits, you can get to higher computational power but not if you have really high error rates. So we have to both move towards lower error rates and higher qubit count, okay? So how do you actually build a quantum computer, right? This is how it should work theoretically. How do you actually go and do this in real life? So first of all, you have to have qubits that work in such a way that you can harness quantum mechanics. So we build basically artificial atoms. Atoms behave quantum mechanically. We build an artificial atom and we make it out of a superconducting Josephson junction coupled to a microwave resonator. So this is what it actually looks like on the chip. You have these squares that are your qubits and these squiggly lines are your microwave resonators and inside of the qubit is a superconducting Josephson junction. And we gotta cool this thing down to 0.015 Kelvin where zero is absolute zero, right? Room temperature is 300. This is significantly colder than outer space. And we talk to the qubits with microwaves. So this is what it actually looks like. This is how we talk to the qubits. We have inside of a dilution refrigerator which you'll see on the next chart. We have all of these microwave cables that allow you to actually go and probe the qubits with microwaves, okay? And this is what it looks like in the actual lab. So these giant white cylinders, these are our dilution refrigerators. And here you can see my friend Nick working on one of the insides of the quantum computer. So great that we can actually do this but did you know you can play with one for free today?  We've hooked up a five qubit quantum computer in the lab through those microwave cables up out of the fridge through the internet available to you at this website for free.  When you do, you're gonna find three different user guides. One is for total beginners. The beginner's guide is no math, just concepts. We're gonna show you visualizations of how the qubits work. We're gonna walk you through early examples of what are the gates you can use? How do they work? How do you think about them? And then you go into the user guide. The user guide is gonna show you some of the linear algebra you need to know. It's gonna show you how algorithms work. We're gonna give you a suggestion of five different algorithms you can run. We're gonna show you what sequence of operations you need to actually implement that algorithm. And then when you're really interested, you're gonna go into the developer guide. This is gonna take you to our API online. It's a sequence of Jupyter notebooks that are written in Python. And you can actually send batch jobs to the quantum computer. Great, just go and learn, right? We're putting it out there for you to learn. This is what it's gonna look like when you click in to the composer tab. On the previous chart, there's three tabs. There's the composer, the user guides, and the community. I'm gonna talk about each of those. This is what it looks like when you click composer. You're gonna get to choose. Do you wanna simulate it? You can choose to simulate where you actually start with two qubits instead of five because it's easier to get started learning with two. Or you can simulate up to 20 qubits. We have a simulator up to 20 qubits. But let's click in to the real device. So clicking in, this is the interface you're gonna see. This is a picture of the actual chip that we have in the lab. You can see those five black squares are our five qubits. And the squiggly lines again are those resonators that we talked to the qubits with those resonators. And here we're giving you some information you may wanna know about the qubits. What's the coherence time? Coherence time is how long does my quantum information last before it gets out of coherence? So for us, we have 50 to 100 microseconds of coherence time. And that matters because it determines how many different operations can I do before I lose my quantum information. Okay, so now let's create superposition. We talked about superposition, let's create it. You drag and drop the different gates that you can perform. There are different logic operations that will be shown on the right. Just drag and drop it onto the graphical user interface. Here I've dragged the H gate into the Hadamard gate onto the score, the line representing the first qubit. And I've done a measurement. And actually these are results I got this morning having run a thousand experiments on the actual quantum computer this morning. And you get roughly 50, 50, zero and one, right? You're in a superposition of zero and one. When you measure it, it randomly chooses. Half the time it chooses zero, half the time it chooses one. If I'm, again, if I'm in a superposition of, if I've got two qubits in superposition then I have four different possible outcomes. Zero, zero, zero, one, one, zero, one, one. So if I measure it a thousand times I get a distribution of each of those possible outcomes. And I can create entanglement. This is how you create entanglement. You put your H gate and then you apply an entanglement gate. This is a C knot. What it says, if I measure the qubit to be zero, don't do anything. If I measure the qubit to be one, flip the second qubit to one. So this is called a bell state and this is an entangled pair of qubits. So you guys can actually go in and create entanglement on a real device in our lab in New York through the internet, which I think is pretty cool. Okay, so now once you get through the beginner's guide and you're really keen, go into the full user guide. This is showing you some of the algorithms that we are enabling you to learn about through the full user guide. If you click into Grover's algorithm you can get a whole derivation of what's going on in that algorithm and we show you this is how you should think about that quantum interference, that amplitude amplification, right? And this is the sequence of gates you need to implement Grover's algorithm on the real device and you can go in and you can actually implement that algorithm on a real quantum computer. So all of this is made possible by a bunch of really committed and passionate makers at IBM. This is a drone's eye view of some of the members of the team outside on the lawn in New York. There's a lot of people that put in a lot of hours to make this available to all of you for free. Okay, and so what are people actually doing with it? We have over 45,000 users worldwide. This is a snapshot of some of them. The white dots represent some of the top universities with the most number of users in the quantum computer. A lot of universities are using it to teach. We have a teacher at EPFL who uses it as part of his quantum information curriculum. We have a teacher at UT Austin. Got teachers all over the world using it. And then we have people just doing really cool and interesting fun things with it. There's a woman, Christine Moran. She's that dot at the South Pole. In between measurements on the South Pole telescope, she's just playing around with a quantum computer, which is really cool.  We telecast a workshop from our Zurich lab to South Africa. So we had three high schools in South Africa just having a quantum information workshop, which is really cool. And this is what those people actually look like. We had Christine in the bottom right at the South Pole. This is the students at the workshop in South Africa. Every summer, starting last summer, so I guess it's only the second year in a row, the University of Waterloo runs a quantum information workshop for their undergraduates. There's a woman, Emily, who, you know, she has a YouTube video that this is I found her on YouTube. She's talking about what it felt like to actually run the algorithms on a real quantum, piece of quantum hardware for the first time. She'd been learning about it in a classroom. She actually got to run it on a real quantum device, which, you know, she talks about being kind of an awesome experience for her. So people are actually using this thing for research. There's been 17, I think at this point, 17 research papers that have been published where someone validates their algorithm on an actual quantum device in a lab. People have made games. There's a guy who created a game called Quantum Battleships, you know? And you actually run the game on the actual processor. So, you know, he's got a blog about it. He walks you through how to actually program the game, how he programmed the game, you know? I just think that's really cool. And people are having fun, right? So the third tab that I mentioned was the community tab. So, you know, in the community, people are asking questions and people in our research team are answering them, right? So what is a CNOT gate? How do I think about that from a mathematical point of view? What is, how come when I have this sequence of gates that doesn't match between experiment and theory? And a lot of the time, you know, because not every gate has perfect accuracy. If you apply too many in a row, then the answer starts to look more randomized because the errors add up.  So that, you know, some of the posts are like, what's your best quantum pun? So, you know, they suggest a couple of drinks like gin entanglement, which I love.  You know, we've all played rock, paper, scissors. There was a whole long discussion on one of the community threads. How do you actually implement rock, paper, scissors on a quantum computer? And actually, you know, I'm in the Slack channel where members of our team, you know, answer the questions. And there was like a whole discussion, an actual, like, theoretical discussion about, well, what is the best way to implement rock, paper, scissors? So, you know, it's just fun. You know, people are having a good time. And as of last week, we put a 16-cubit device online for beta users. So this is, you know, this is the most advanced public quantum computer available anywhere and it's free.  And, you know, we also had an announcement where we doubled our quantum volume. So not only did we announce 16 qubits, we have another device with double the quantum volume. And there's a picture of Katie in New York in Times Square next to one of our quantum computers. So, I encourage all of you to visit our booth. We have a booth in Building 2. You can come and learn. We have at least two different demos that explain to you how does a qubit work.  And we'll show you a demo of the experience, right? You can go in and you've got that five qubit interface. We've got it up at the booth. You can drag and drop gates. You can create entanglement in a real device online. And we've actually hooked up also some LEDs so that you can actually visualize the results of your experiments.   You know, we've opened up this quantum computer, done it for a few reasons. One of the reasons is we'd love to know what you wanna do with it. What are the things you guys wanna do with it, right? We encourage all of you to go off and make something and share what's your ideas with us. And we'd love to hear about it. So, thank you all for your attention.


a start, a continuation and intermission. We all view this day from a different perspective. A few years ago, we embarked on a journey of finding a place for ourselves, a career path with which we would be satisfied. As we approach this campus, we were greeted by bleak walls within which, lectures awaited, PowerPoint presentations were looming, assignments seemed to be the order of the day while grades stared sturdily in the face. Some were apprehensive, some were excited, while others who viewed it as just another step approached it with indifference. We were all forced, some more than others, to make adjustments. For some, the pressure to fit in with the multicolored additions to the uniforms and high heels and stockings were sometimes overwhelming. It was difficult to be the student once again and not the teacher, and adapting to those time schedules which demanded every second of our lives was a great challenge. This was a different time, a different place, which demanded everything from all of us. No longer will we be surrounded by colleagues of just our age group, but in our midst, were persons who could be our parents and some who could be our children. In fact, some did become mothers, fathers, husbands, wives, and notched at those of us who still remain children. Regardless of where we came from or who we were, we shared our hobbies, our personal lives. Sometimes we twiddled our thumbs and counted stars in the hope that someday, like today, we would become a star. It was Martin Luther King, Jr. who first had a dream. At the beginning of this journey, I too had a dream. I had a dream to see this day and beyond. As the road stretched ahead, the journey seemed impossible. The end, distant. Nevertheless, our lecturers smilingly propelled us forward with PowerPoint presentations, projects, assignments, and a list of activities which seemed never-ending. Some of us, unprepared for the potholes filled with challenges that looked in the corners where we least expected, fell flat on our faces. For some, the journey was too overwhelming, so they said farewell before they could say a proper hello. However, those of us seated here today saw the green lights of encouragement, skillfully dodged the reckless drivers called discouragement and refused to be bulldozed by those long vehicles with assignments, tutorials, projects, and exams. We put on shields of determination and armed ourselves with the will to succeed. However, as we became comfortable in our chairs and adapted to the unbearable sounds of the weed eater every Monday morning, we exploited our flexible hours, which some of us regarded as freedom. The classrooms were no longer filled to capacity as persons ditched classes daily to complete yesterday's assignments or to rush to town to splurge in the wings of love sale, or just to avoid another PowerPoint presentation. While the workload did not prove difficult, 168 hours multiplied by four at times seemed insufficient to complete the work. So we prayed on our understanding lecturers who sometimes gave us extensions and the patient secretaries and office staff who became our lifelines. These kind individuals who were less strangers at first would wait for us to staple and bind all of our assignments. We all enjoyed those long lines at the Reprographic Center, otherwise known to us as the Reporph. Every student visited that center on a daily basis to print, reprint, bind, or complain about the prices. Despite our grumbling, Dwight and Tony, who just served, laughed and teased us because they knew that someday, like today, we would look back and somehow miss them. I bet now they are enjoying the new plight of students, that included. We shook hands and journeyed with a combination of characters. And for these few years, Soapha Lewis Community College began to feel like the television network USA Characters welcomed. We hosted the jokers who stepped in from time to time. The book hoggers whom we wish should fall off the edge of the cliff. The library worms we hoped would disappear under the earth. The limers we pretended not to notice. But more importantly, we welcomed you, the talkers, the writers, the singers, the painters, and those of unknown talents. And the bonds, all the bonds that we form at this place. It was said that some people come into our lives for a reason, some for a season, and others for a lifetime. And we proved that right here, as some of us became friends forever. So as the songwriter Vitamin C aptly puts it, as we go on, we remember all the times we shared together.  Take a look at the persons who shared in your laughter, or who wiped your tears when things were just not going right. Take a look at the persons who encouraged you to miss that one o'clock class to continue some uncensored or unrelated school discussion. Then laugh at you when you were caught in the act. We journeyed on. We journeyed on after the effects of Thomas, Hurricane Thomas. That hurricane instilled a sense of respect combined with fear of the rain. We were also edgy and frightened when the rains came. We sought early dismissal from five o'clock classes to head home in the south.  Despite its destruction, this storm strengthened the bonds among students as individuals were always on guard for those who lived or passed through areas including Chumase and Bexor because of the river. Wasen Slep Martin 1958 was the one who said that success is not measured by how much you accomplish, but the opposition you have overcome and the courage you have maintained to the struggle against all odds. Each one of us is a representation of the challenges we have overcome to earn our place at this momentous occasion. For those of us who are unfamiliar with leftovers but acquired an appetite for that day, Kushe, this is your day. For those of us who appreciated the value of a dollar because we spent $20 or more daily only on bus fare, this is your day. For those of us without the luxuries of textbooks, computers, who stole wireless just to complete that assignment on time, this is your day also. For all of us who saw the break of dawn without sleep for nights on end because we were dotting our eyes and crossing our teeth, only to be slapped if an exam two hours later, we made it. The words of Henry Wadsworth 1982 summed the experience nicely. The heights by great men reached and kept were not attained by sudden flight, but while the companions slept, they were toiling upward through the night. It is with honor and great pride I say to you, it was all worth it. So our creator whom we owe everything to for his sifts as mercies, guidance and strength, we say thank you. Thank you for walking us through this journey and carrying us when the road was too much. So the staff of the Soapha Louise Community College, we say a heartfelt thank you. We appreciate the contribution you made to our journey here. So the lecturers, we are forever indebted to you for your time, patience, understanding, along with all those teachable moments we consider gibberish at the time. To our families who supported us throughout this journey, we say thank you. Thank you for tolerating our books, chats, cutouts, our bags on the floor, on the table, on the bed. Thank you for just sitting with us when we did assignments and just needed the company. We appreciate your love, support and tolerance. To my fellow graduates, as we continue our journey beyond the walls of the Soapha Louise Community College, let us take with us the lessons learned, the values instilled and the friendships cultivated. Charles Dickens said, the pain of parting is nothing to the joy of meeting again. Among us are scientists, farmers, doctors, ministers, nurses, teachers, no matter the career path, let us endeavor to positively impact the lives entrusted in our care and the world by extension. In closing, I would like every one of you to raise your right hand. Raise them, raise them. Place it on the person sitting to your right. I can now safely say that my speech has touched everyone here today. Our journey has not ended. We just completed another leg. And as for my dream, it is still in the making. Congratulations everyone, this is your time. You have worked hard, reap the rewards. I thank you.


Yeah, so thank you very much. Very good afternoon to all of you. This is Nenu Somraj. I am an Indian Forest Service Officer. I'm a bureaucrat working in one of the state of India, Maharashtra. And I present, I'm looking after the mangroves and marine biodiversity in the Mumbai city and Maharashtra state. So here, I would like to bring the topic on, it's a case study. In fact, it's a case study on mangrove conservation happening around Mumbai Metropolis. And before going into detail, so for, you know, activities, I would like to introduce you Mumbai city to all of you. So some of you might have heard about it. So this is the capital city of Indian state of Maharashtra. And it's a global financial and a commercial hub. So the city is very, very crowded and it's very, very popular. So you can see that it's most, sixth the most populous metropolitan region in the world, having a population of more than 23 million. They are living on over an area of 6,500 kilometers. So we understand that it's very, very crowded. Yeah, sometimes I can see that over crowded city.  So previously, Mumbai was known as Bombay. And when previously it was a group of seven islands. So when the British came in our country, and in the 18th century, they understood the commercial potential of the sport city. And they reclaimed all this land in between the seven islands and reshaped and don't have the present form. And so here on the right side, you can see by diversity map of Mumbai city, Mumbai metropolitan region. So which was prepared by Mumbai metropolitan region development authority in the year 2011. So, so here, I'm concerned about the mangroves here on the map, you can see our red color areas. So this is the mangroves is very, very close to the western cost of India towards the cost aside, we can see so many big creeks and small creeklets. So because it's a reclaimed city, the city is in the sparse with bias many creeks and creeks and home to rich mangroves and associated by the city. So, as I mentioned, how do you do is they were growing population this, you know, city face the huge migration from the nearby villages and, you know, the mangroves, the mangroves in the city really faced so many things. So lots of mangrove forest have been diverted for development projects and for industries and for even agricultural projects and even even migrant population cut down a part of mangrove forest in the developed day slums and, you know, human settlement. So so unfortunately because of all this surrounding illegal activities the city witnessed more than 60% of loss of mangrove cover in the past. And here, we will know that why mangroves is important and why it's very, very, very essential to be conserved for the sustainability of a city like Mumbai, because, you know, being a coastal city, this Mumbai is located on the west coast of India subcontinent. And this is very much, and the city is facing all the threat of climate change, like sea level rise and, you know, erratic weather events like the tropical cyclones etc. And mangroves act as a bioshield in providing this kind of thing and helping the city, hence it's very, very imperative to conserve these mangroves in the city. And similarly, this mangroves act as a hub of biodiversity as a home to many migratory water birds and other marine organisms in water birds and economically important fishes and shrimps. And incidentally, I can tell you very much that this mangrove forest really supporting very much in the sustainable fishery industries and helping the local income generation for the local people's communities. And also, considering all this fact, and since the Mumbai witnessed the disproportionate reduction in the mangrove cover, all the government agencies, judiciary and the community organizations, civil society organizations joined together. In the year 2005, judiciary, the High Court of Mumbai came up with the progumentary order, which sees that, you know, all development activities, all conversions of mangrove forests and buffers on 50 meter buffers, they completely banned. So I consider this as a watershed here in the conservation or in the history of conservation of mangroves in Maharashtra state and particularly in Mumbai. So, in order to protect these mangrove forests in the city and the state, so the state government created a special dedicated unit. So this is known as mangrove cell, and personally I'm working in the mangrove cell, I'm working as a deputy conservator of forest and the joint director of mangrove foundation. So, our first task was to identify these mangroves in the government land and the public land. So, we identified such mangrove forest in the government ownership and brought those land in a legal protection framework in India, it is known as reserve forest. So it is the highest order of protection as per Indian Forest Act 1927. This was our first step. So, but then after the identification and the mapping of these land, we understood that lots of encroachment happened even within the boundary of the reserve forest and our next task was to remove all the illegal encroachment on the mangrove forest and that's a continual process but thankfully we could remove, you know, almost 95% of encroachment in Mumbai city and it's a more than 8000 illegal settlement. So, considering the industrial importance and the commercial importance and the population, it's really difficult task in, you know, demolishing all this structures and protecting this land. So, we have to do some policing also in this place. So, we adopted concept of green policing in Mumbai and so deployed security forces, the enormous Maharashtra security force, they have been deployed in sensitive locations which are very much prone to all diversions and destruction and these police are doing all these tasks in 24 by 7 bases and protecting these lands from further encroachment. And another topic was to restore the, you know, degraded mangrove forest and for that purpose we initiated huge massive mangrove plantation programs and more than 735 hectares of area in this metropolitan region has been restored back and we have separated mangrove nurseries in different places and even so far more than 30 lakhs of seedlings have been utilized in our plantation program. So, you can see the photographs of mangrove nurseries and the mangrove plantation here we adopt a special technique known as fish bone channeling for the restoration of the mangroves in the blank and degraded forest area. These fish bone channels really help in allowing the salt water into the land, into the interior part and helping the mangrove seedlings to try. And the main issue is making this mangrove forest more cleaner and more healthier to support more biodiversity. For that purpose a clean mangrove campaign was initiated in a different part of Mumbai Metropolitan Police to remove all the solid waste and plastic waste from the mangroves and make it more hygienic and to support all this, you know, water boards and other organisms and also for more than 8000 tons of solid waste and the plastic waste have been removed from this forest. This is a continuous process and for that purpose we are in partnership with the various organizations like non-governmental organizations and civil societies to conduct this kind of programs and it's a part of our outreach programs also since as college students and school students are also joining in the clean mangrove campaigns and it really helps in creating awareness about keeping this mangrove area more clean. Can I just interrupt briefly? This is an extremely interesting and very important case but we are out of time. Could you slowly or I mean rather quickly wrap up. Perfect and I'll invite any questions to the chat but yeah we're over time now. I am so sorry to do that because I was really enjoying your presentation. Yes, thank you very much. So this is my last slide only. I can just tell about the biodiversity of Mumbai so we have a creek in the city of Mumbai which is a part of the Central Asian Highway for migratory birds and to protect these lands so we brought this land under a marine protected area so it's known as Tannic Big Flamingo Sanctuary which is home to many birds like the Flamingos, Greater Flamingos, and the lesser Flamingos more than one lakh birds do migrate to this place. So this was another work on conserving the biodiversity and the result was really awesome that now we have more than one 10 square kilometre of mangroves in Mumbai city and this all happens due to the stringent protection and the conservation and the restorations. Thank you.


So, welcome to the second lecture of cryogenic engineering and the NPTEL program. In lecture 1, I gave you a brief outline of the syllabus that I am going to cover in this subject on cryogenic engineering. At the same time, I gave you a brief review of different applications of cryogenics in various field. We talked about space, mechanical engineering, medicine, superconducting devices etcetera. Having done that, what is most important is how to get lower and lower temperatures, what are different cryogens, what are their properties and this is what we are going to see in this lecture. So, the outline of my today's lecture is, again I will briefly just revise the definition of what is cryogenics. Then I will talk about the chronology of cryogenic technology. The cryogenic technology spans for around 125 years. Since the first research or first innovation happened in this area and it is very important to study how the development or evolution in cryogenic technology happened over last 125 to 30 years. After that, I will cover in brief the definitions and different temperature scales that are normally used in cryogenic engineering. Then one of the most important diagram is what is called as temperature entropy diagram for any fluid wherein you can really get all the properties of different cryogens and if you have a critical look at this diagram, lot of things are getting clear from this diagram regarding those cryogens and the temperatures associated with those cryogens. So, it is a very important diagram and normally all the mechanical engineers would deal with T S diagram. So, therefore, I would like to introduce you to this diagram and understand what exactly T S diagram is. And finally, today I will touch a few cryogens, what are the properties of those cryogenic fluids and in the next lecture also, I would continue with this cryogenic fluids. What is cryogenics? Cryo is very cold as cold as I see, although cryogenics means very, very low temperature but the name is coming from as cold as ice. Then genics is to produce. So, basically cryogenics is nothing but science and art of producing very cold that is what I find earlier and still today the definition carries. As I said, the chronology in the cryogenic engineering is very important and we will see how different events unfolded over the years worldwide. So, really speaking, the first development happened in 1877 where as you understand, oxygen is the most important gas for all of us, the question of life basically. So, as you can understand, the first development was towards liquefaction of oxygen, therefore storage of oxygen and oxygen gas and chylotate and pictate in 1877, almost 133 years before, we had first liquefaction of oxygen and oxygen liquefies at around 90 Kelvin. And both of them actually presented a paper on liquefaction of oxygen in a conference in Paris. However, both of them worked independently. In fact, pictate device, they are available, both the devices are available on NET if you want to get more and more information or in books also. Pictate basically came from Switzerland from the University of Geneva, was a physicist. Chylotate was a mining engineer and in 1877, pictate liquefied oxygen and what he used is a basically cascade kind of a refrigeration system where sulphur dioxide and CO2 or liquefied CO2 was used to liquefy oxygen. Oxygen was pressurized to very high pressure of around 320 bar and it was liquefied at around minus 140 degree centigrade. Well, in pictate here in this case, having pre-cooled the gas to particular temperature, ultimately he expanded the gas using a simple Joule-Thompson expansion or capillary tube. Similarly, chylotate also did the pre-cooling of oxygen gas, however he did it at 200 bar and he used ethylene for pre-cooling up to minus 100 degree centigrade around and then again expanded the gas using Joule-Thompson expansion device. So, basically they followed a kind of similar technique, however they were pre-cooling refrigerants very different, but the funniest part was both of them did the independent study and presented in the same year at the same conference. Now, in those days in 1877, however they did not know how to store liquid oxygen, they got a mist, they got some fog, they got some condensate, but they did not know how to store that. So, that time that knowledge was not there, it came later on. The next development happened just two years after that where Lindey founded Lindey Ice Machinen AG. This is a private company which Lindey founded and Lindey is a big name in cryogenics. In fact, this company which came into existence in 1879, it became Lindey AG in 1965 and most of the companies are under this umbrella of Lindey now. It is a very big name in cryogenics, it is in India also and here for the first time the modern domestic refrigerator was kind of shown by Lindey. The next development happened in 1892. As I said, in those years in 1877, the facility of storing liquid cryogen was not there and Devar, a device is named after this scientist called Devar. He developed a vacuum insulated vessel for cryogenic fluid storage. So, here for the first time he understood the importance of a double walled flask with vacuum in between and he showed in principle how one can store liquid nitrogen, liquid oxygen for a long time which otherwise used to get evaporated immediately and this is a very very important development for cryogenic engineers and the vessel in which we store liquid cryogen is also called as nitrogen Devar or helium Devar named after this particular scientist. The next important development happened by a very big scientist called Kemmerling Onnes from Leiden laboratory in Netherlands in 1895. Kemmerling Onnes is a very big name again and he was a physicist, he was a professor at Leiden University in Netherlands and here he founded cryogenic laboratory at this place and he invited lot of people all over the world to work at this laboratory. Next in 1902, Clouday for the first time he found a next company called Air Liquid in France where commercial air liquefies were made available. So, first we had Linde and then we had Clouday as two commercial companies came into existence in Europe, this company came into existence in France and they had commercial air liquefies available worldwide. So, this was beginning of real commercial cryogenic engineering. Onnes, Kemmerling Onnes after founding this Leiden laboratory cryogenics laboratory at Leiden in 1908 he liquefied helium. See all this development if you could see was towards lowering and lowering of temperatures. Here we had 90 Kelvin, I forgot to mention here in 1898 Devar for the first time liquefied nitrogen that means he could get 77 Kelvin here. If you come down below in 1908 Onnes liquefied helium that means he could reach the temperature of 4.2 Kelvin, this is the most important thing that happened. Now, there is a very typical connection to India in this particular case that the helium gas which Onnes utilized for liquefaction it had some Indian connection. He had used monazite sand from India and when he heated this monazite sand he got helium gas. So, he used this particular gas to liquefy and then he got liquid helium in 1908. So, you can imagine in the year 2008 we completed 100 years for helium liquefaction and we all celebrated that as a centenary year of liquid helium. In India we had a big conference in Indonesia of science which celebrated the centenary year of liquid helium. Having liquefied helium the next action is to utilize this liquid helium so that one could find different properties of metals and in 1911 Camerling Onnes discovered superconductivity phenomenon. As you understand as you go on lowering the temperature of a metal the metal become more and more conductive the resistance become almost equal to 0 and it shows in principle the phenomena called superconductivity. So, once you get lower and lower temperature Camerling Onnes in the year 1911 showed that mercury becomes superconducting at 4.2 Kelvin and this was a very big phenomena which was discovered then and for this phenomena he got Nobel Prize in the year 1930. Onnes got around 60 cc of helium in this experiment at this point I just wanted to mention this point over here. Then next important developments happened with engineering as a more in application area in 1926 Goddard test fired the first cryogenically proper rocket. So, he could use the cryogenic fluid for the propulsion of big test rockets big rockets and here he had used gasoline and liquid oxygen. So, he uses gasoline as a fuel and use liquid oxygen as an oxidizer propel the rocket as you know the cryogenic engine what today we use uses liquid hydrogen as a fuel and liquid oxygen as an oxidizer but at this point in time use gasoline as the fuel. In the year 1934 Capitza again a very big name in cryogenic engineering in he used for the first time a turbo expansion engine and he could get liquid using the turbo expansion engine without the pre cooling and this happened to be major development to be used in liquid fires later in commercial applications. In the year 1952 one of the very big institutes came into existence called National Institute of Standards and Technology or NIST formally known as National Bureau of Standards NBS it is at Colorado in USA and here first cryogenic engineering laboratory got established where real innovation in US started. In fact most of the conferences what we see today as CEC that is cryogenic engineering conference or cryocooler conference this originated from with the initiatives taken by NIST lot of innovations happened at this place in NIST. Going ahead from here in 1966 what we got was a development of dilution refrigerator. Having achieved 4.2 Kelvin liquid helium temperature scientists started working towards going lower and lower in temperature as I said most of the development happened towards lowering of the temperatures to reach first 4.2 Kelvin and then to go below 4.2 Kelvin. So dilution refrigerator was a device which uses helium 4 and the other isotope of helium that is helium 3 in combination together we will study about this also later on and one could reach down lower in temperature below 1 Kelvin and this was the concept which is a very important concept going below 1 Kelvin. A dilution refrigerator came into existence and lot of research below 1 Kelvin one could really go for the device was available then and the properties of material could be studied below 1 Kelvin. Superconductivity research was very much high in those days what you know actually is you got a low TC material for which the low temperatures required for superconductivity. High TC superconductors are normally using liquid nitrogen for cooling arrangement that means mostly these superconductors work above liquid nitrogen temperatures. And here first time one could go up to 23 Kelvin where superconductivity could be established in material. This is a very important concept because it is very costly to reach 4.2 Kelvin in order to utilize helium at 4.2 Kelvin but the attempts were always there to use liquid nitrogen at 77 Kelvin. So scientists always crave to invent new and new materials which will show superconductivity at higher and higher temperature. So this was the first time in 1975 that they could show superconductivity at a high temperature of around 23 Kelvin. And then in 1994 cryocooler development took a big turn where Professor Matsubara from Nihon University Japan developed a 4K cryocooler working on the pulse tube technology and called pulse tube cryocooler. Here the pulse tube cryocooler or Gifford-McMon cryocooler or Sterling cryocoolers were already there and they are as you know is close cycle cryocoolers. So attempts were always going on, the research was always going on in order to avoid use of liquid nitrogen or liquid helium which require continuous replenishment because they get evaporated over a period of time. So the research was always going on in order to generate these lower temperatures in a close cycle manner so that different cryo genes like liquid helium, liquid nitrogen or liquid oxygen etcetera will not be required to be used. And here for the first time could show pulse tube cryocooler reaching 4K temperature in a close cycle manner. Now you can imagine I got a device which can produce 4K temperature in a continuous manner in a close cycle fashion where the gas is getting compressed and expanded and producing temperature of 4 Kelvin continuously and I do not have to really worry about any cryo gene replenishment at all and that was a major breakthrough and then lot of research initiated in the area of this pulse tube cryocooler to reach lower and lower temperature and now one can reach even 1.5 Kelvin or 1.2 Kelvin using again helium 3 or helium 4 as a gas and one can really reach lower and lower temperature below 4 Kelvin also. This was a major breakthrough as you could see from this that lot of events happen from almost 7 through to almost year 2000 and after that where things change from oxygen liquefaction and it came down to helium liquefaction and the temperature went below that of liquid helium. This is a major developments happen over the years and now from here once the chronology is complete I will introduce again what is cryogenics. As I told in the earlier lecture cryogenics is a science and technology associated with generation of low temperature below 1.23 Kelvin and I told you earlier in my last lecture that I will talk more about why this 1.23 Kelvin what is the logic behind this let us see this. So this 1.23 Kelvin is a dividing line between cryogenics and refrigeration. You can see all this under the title of cryogenics I have got different gases who have got their boiling points below 1.23 Kelvin and on the right side of this dividing line I got a process called refrigeration where all these gases all the refrigerants have their boiling points above 1.23 Kelvin. So here I call cryogenics below 1.23 Kelvin sometimes this could be 1.20 Kelvin some people define below 92 Kelvin also. So one can have various definition of cryogenic range or cryogenic temperature. So below 1.23 Kelvin what I call is cryogenics and above 1.23 Kelvin below the room temperature what I call is refrigeration. So this line as I said could be as broad as from 90 to 125 Kelvin depending on the definition given by various researchers. Now what was the logic of having this division at 1.23 Kelvin as you can see all these gases where earlier called as permanent gases. It was thought that these gases could never be liquefied they tried to liquefy those gases at room temperature by pressurizing these gases. One can get all these gases on the right side they can get converted to liquid if you pressurize these gases. However, if you talk about these gases even if you pressurize them at room temperature to a very high pressure when I say high pressure it could be of the order of 300 to 400 bar it could be very high pressure but in this case these gases will not get liquefied. So you have to use some different techniques to go below the room temperature and then liquefy these gases. These were classified as permanent gases thinking that these gases can never be liquefied and therefore this dividing line came into existence of around 120 Kelvin and on the left side of it what we call as a cryogenic engineering on the right side of this what we call as a refrigeration. Again I said that the exact value of this could be varying depending on the reference and the person or the scientist to whom you are talking about. Now in cryogenics we talk about different scales we have got different scales available for temperature measurements. We have got a Kelvin scale, we have got a Celsius scale, we have got Rankine scale and we have got a Fahrenheit scale. So in principle I can give temperature in Kelvin or in degree Celsius or in degree Rankine or in degree Fahrenheit. If you could see here when I talk about Celsius I got 0 degree centigrade and I got minus 273 degree centigrade which equivalent to the 0 Kelvin here. At the same time in Fahrenheit scale I got minus 459.67 as 0 Kelvin that means a temperature when I talking about below 123 Kelvin I have to every time refer to minus something degree Celsius or minus something degree Fahrenheit which normally is avoidable. If I want to say 77 Kelvin, 77 Kelvin is very simple for me to say all to remember instead of saying minus 196 degree centigrade if I want to avoid that thing I would always prefer to talk in Kelvin or I would always prefer to talk in Rankine because Rankine scale also is always positive scale 0 and positive scale Kelvin also is a 0 and 0 and positive scale. The most preferred scales therefore in cryogenics are Kelvin and Rankine. So if you see various books you can always see that the temperatures are normally given in Kelvin or in Rankine and not normally in Celsius and in Fahrenheit. However, one can always have any temperature scales it is not must that one should use always Kelvin or Rankine it is completely left to the convenience of a person and what he appreciates the temperature scale as. So if I were to use Kelvin and Rankine or Celsius and Fahrenheit scale if I talk about increment that means if I say I incremented the temperature by one Kelvin it will amount to 1 degree centigrade here or it will amount to 1.8 degree Rankine or it will amount to 1.8 degree Fahrenheit. So you can understand from here that if I increase the temperature from 50 Kelvin to 52 Kelvin it will mean that I also increase the temperature in Celsius by 2 degree centigrade. However, it means in Rankine that I increase the 2 Kelvin that means 3.6 degree Rankine and there is a increase of 3.6 degree Fahrenheit in the Fahrenheit scale. Normally I will refer only in Kelvin in my further discussion in cryogenics I will always refer temperatures in Kelvin range. So the Kelvin temperature range is normally whatever degree centigrade plus 273 degree centigrade. What is important to note here is it is only Kelvin it is not degree Kelvin while all other temperature scales are degree centigrade, degree Rankine and degree Fahrenheit but while referring to Kelvin I will say 20 Kelvin and not 20 degree Kelvin this is a mistake lot of people do and therefore I would like to point out that it is only Kelvin and not degree Kelvin. In cryogenics normally in India I will always refer room temperature normally as 300 Kelvin assuming that it is 27 degree centigrade room temperature I will call 300 Kelvin as my room temperature this will be this will be studied more in the problems or while discussion I will always call the room temperature is 1 atmosphere and 300 Kelvin. Just to give an idea about different temperatures the different cryogenes which are broadly used are liquid nitrogen, liquid hydrogen and liquid helium and their boiling points are 77.36 Kelvin, 20.39 Kelvin and 4.2 Kelvin. Just to give a cost comparison of this cryogenes the liquid nitrogen generally produce across let us say in India cost only 25 rupees per litre if you buy let us say in lump of let us say 100 litres while if I go and buy liquid helium in the market it will cost more than 1000 rupees per litre if again bought in 100 or 500 litres at one time. This comparison gives you an idea what are the costs associated with liquid nitrogen which becomes liquid at 77 Kelvin and cost associated with liquid helium which will liquefies at 4.2 Kelvin. Do not forget that helium is a rare gas it is not generally available and nitrogen is available all over. So, we got a air which is mixture of 79 percent nitrogen and 20 percent oxygen and therefore nitrogen available everywhere and therefore the cost of nitrogen is not so much as compared to the cost of liquid helium. Now, the fluids or the cryogenic fluids normally are referred as cryogens which are the fluid with normal boiling point less than 123 Kelvin which we have seen earlier. Now, there are different cryogenes we have got a methane which has got the boiling point of 111 Kelvin and a triple point that means if you go on still reducing the temperature over the particular liquid it will become solid at 90.69 Kelvin similarly, oxygen boiling point of 90.19 and it has a triple point that means it will get solidified at 54 Kelvin, argon at 87 Kelvin and 83 Kelvin note that there is only 4 Kelvin difference between the liquefaction or the boiling point and the solidification point. Air which is a mixture of so many gases has a boiling point of 78.6 note that the 78.6 is very close to 77.36 which is a boiling point of nitrogen and it is triple point is 59.75 Kelvin. Similarly, nitrogen 77.36 with a triple point or a solidification point at 63.15 and hydrogen has a boiling point as 20.39 Kelvin with a triple point of 13.96 Kelvin. It may be noted all these triple points are below atmospheric pressures alright so it will not get solidified at room temperature but if you go on removing the pressure or decrease in the pressure over these gases over these liquids then it will reach this solidification point. While you can see here the boiling point of helium 4 is 4.2 Kelvin and its isotope of helium 3 is 3.19 Kelvin and they will never get solidified or there is no triple point not that they will not get solidified but there is no triple point for this particular liquids or gases. Now one of the most important thing is the temperature entropy diagram of a cryogen. In mechanical engineering as I introduce initially most of the cryogens properties are given in TS diagram or a temperature entropy diagram. In future whenever we solve some problem related to liquefaction or refrigeration what I do first is draw the cycle in a TS diagram. So here on this TS diagram I understand for a given cryogen what will happen if I compress this cryogen, what will happen if I expand this cryogen, what will happen if I want to liquefy this cryogen and all this can be understood on a TS diagram or a temperature entropy diagram. So here on a y axis normally temperatures are given in Kelvin and on the x axis what you see is entropy. Now what you can see here is a kind of a dome and inside this dome what you have normally is a 2 phase fluid that means you will have liquid plus vapor inside this dome. This right side is saturated vapor line on the left side what you see here is a saturated liquid line. This line which is in red in color is a constant pressure line you can call it isobaric line and the point which I am showing over here is a room temperature point which is the temperature is 300 Kelvin and the pressure is 1 atmosphere and the point is A. It is very important for every cryogen TS diagram to first see where we are what is our room temperature and 1 atmosphere pressure. So pressure 1 atmosphere and 300 Kelvin temperature so if I go horizontally on this side I will hit 300 Kelvin over here. So you can see point A and point B and point E here I am basically reducing the temperature at 1 atmosphere pressure of a gas and then reaching point B and then reaching point E which is a saturated vapor line. So you can see vapor on this side and if I further come down to this point E and then reduce the temperature further I will not get reduction in temperature but what I will get here is change of phase and this change of phase is going to convert this gas from vapor state to liquid state and what you get in between is a liquid plus vapor. So here what I got inside this is a two phase mixture and at this point F what I get is a 100 percent liquid at point 8 E what I got is a 100 percent vapor and in between depending on where I am mixture of liquid plus vapor. So if I were to liquefy any gases I have to first arrange to reach in this region and then separate liquid from here this is the most important thing. So what is happening between E and F is a change of phase and this length of line from E to F is actually indicative of the amount of latent heat that would be there for the gas at one bar pressure. You can imagine I can draw various curves for various pressures that means this is a line for 1 atmosphere I will have a line for 5 atmosphere I will have a line for 10 atmosphere like this and all the horizontal lines here will represent the latent heat associated with those pressures and if I go further reducing the temperature what I will get is a sub cooled liquid and the temperature will stop dropping down will go on dropping down further. So what you call this point of E and F the line join E and F if I continue on temperature axis what is it is nothing but the normal boiling point. If I talk about liquid helium or if I talk about helium gas this point will be 4.2 Kelvin if I talk about nitrogen this point will be 77.36 Kelvin alright. What is this point? This is a critical point a critical point has got liquid and vapor there is no phase differentiation between these two you can see that if I go on increase in the pressure my latent heat start reducing the latent heat is becoming less and less as I increase the pressure and at this particular point there is no latent heat that is one cannot differentiate between liquid and the vapor at this particular point and it is called as critical point. The temperatures and pressures associated with this are called critical temperature and critical pressure it is a very significant to understand what the critical temperatures of any gas what does it mean? It means that above the critical temperature what I have got here is a gas below the critical temperature what I can have is a two phase liquid plus vapor I can get only when my temperature is below the critical temperature. And similarly with pressure lines if I am coming down over here if I am above the critical pressure I will never come in the two phase dome I will bypass this two phase zone and I will drop on this side while if my pressure is below the critical pressure then I will definitely reach inside the dome and therefore if I tell you any state of a gas in terms of temperature and pressure I can immediately know what are corresponding critical pressures and temperature of this gas and therefore I will know whether it is in gaseous stage or it can be in two phase region also. So, if I want to liquefy the gas if I want to liquefy the gas the pressure what I should have is going to be less than critical pressure so that I can be in this dome and this is a very important thing that one should have temperature of a gas less than critical temperature less than critical pressure then only one can fall in a two phase dome then only one can get liquid plus vapor or liquid can be separated from this liquid for plus vapor then. Now, I will show actual properties of some of the cryogens and then we will see the T s diagram of some of the cryogens. So, here you can see that I got liquid helium I got liquid hydrogen nitrogen liquid air and liquid oxygen and some properties for comparison. So, if I compare their normal boiling point which you know now it is 4.2 20 Kelvin let us say 77 Kelvin 78 Kelvin and 90 Kelvin these are the boiling points in increasing order from liquid helium to liquid oxygen the critical pressures are also in the order of their boiling points. So, you can say 0.2 to 9 MPa which means 2.29 bar or 1.3 MPa 3.39 MPa 3.92 MPa and 5.08 MPa. So, very close following the normal boiling points the critical pressures are also increasing with their boiling points. If you see density the density of liquid helium is 124.8 for practical purpose we say 125 kg per meter cube then liquid hydrogen density is 70 kg per meter cube and if you see nitrogen it is very high 800 807 kg per meter cube liquid air is 874 and liquid oxygen is 1141. So, densities are very high as you go on this side. Latent heat is a very important parameter in order to see how much cooling effect one gets with the change of phase. So, if I get liquid helium at 4.2 Kelvin the latent heat is very small 20.9 that means it will get immediately evaporated while it is not true with liquid hydrogen which has got a very high latent heat. Similarly, for liquid nitrogen it is around 200 kilo joule per kg 205 for liquid air and 213 for liquid oxygen. So, you can see relative values of the latent heat for this cryogens. Now, here I am showing a TS diagram for helium you can see how actually it looks and on this chart we have shown different curves which give pressure temperatures entropy density enthalpy lines etcetera. So, here I have just pointed to you a one bar isobaric line and here if you come down I am not sure whether you can see, but what you have is a 4.2 Kelvin and this is one atmosphere and 4.2 Kelvin which is nothing, but the boiling point of helium. So, here you can see that if I come down this way I will reach 4.2 Kelvin at this point and this is the dome here inside which I am having liquid plus vapor a two phase mixture of helium. While above this point which is a critical point here at this point it is a critical point and the critical point is 2.29 atmosphere that is a critical pressure and the critical temperature is 5.2 Kelvin. That means if the temperature of the gas is above 5.2 Kelvin I am somewhere above this line if I draw a horizontal line here the gas is above 5.2 Kelvin. Similarly, if my pressure is above 2.29 atmosphere then I can never be inside the dome that is the meaning of critical points pressure and temperature for helium gas. So, here what you can also see are these lines which is nothing, but isenthalpic line or the enthalpy line. So, if I draw any state for example, this state I will know enthalpy at that point I will know temperature at that point I will know density at that point I will know entropy at that point and therefore, all the thermodynamic activities which I do for example, compression and expansion I can plot all those actions on a TS diagram of a particular cryogen. These are the constant pressure line 1 and the 2 and the 3 and at critical point what you see 2.29 and this line is of 3 atmosphere. So, this point close to this point the line of 2.29 atmosphere would go. So, any action if I got a isothermal compression that means, I will go this way I am going to compress the gas from 1 atmosphere to higher pressure while temperature is maintained constant. Similarly, if I got a isentropic expansion then I will go vertically down where the entropy remains constant alright. So, when one can have a isenthalpic expansion isentropic expansion isothermal compression all these action can be shown over here. As you can see these are isenthalpic line and if I got a isenthalpic expansion from higher pressure to low pressure I would travel across these lines and this is what it helps to build a cryogenic system of different compressions and expansion in order to get liquefaction of gases or refrigeration. This is the most important part and we will deal with such diagrams hence in the next lecture when we deal with liquefaction and refrigeration of different gases. Similarly, I am showing you one more diagram for nitrogen where you can see a isobaric line from this place at 1 bar and corresponding to that what you have got is a 1 atmospheric pressure which is this line and what you see is a 77.36 Kelvin temperature corresponding length in this dome this is a dome and this length is nothing but representing the latent heat part associated with this gas at 1 atmosphere pressure. Again you can see isenthalpic line and density line entropy line etcetera. This point which is the apex point of this dome denotes the critical point and the critical parameters here are 39.9 atmosphere and 126 Kelvin. 126 Kelvin is a critical temperature for nitrogen and 33.9 atmosphere is the critical pressure for nitrogen here in this case. So, as I said the TS diagram forms very important reading for this cryogens and it is very important to understand and follow these diagrams critically. So, having seen the TS diagram or the temperature entropy diagram for various cryogens and its importance now I will talk about cryogenic fluids and their properties some characteristics and some distinct uses. The most important cryogens normally for very low temperatures used are hydrogen and helium and they come in a very special class and therefore, I will deal with them in the next two lectures for liquid hydrogen as well as for liquid helium at 20 Kelvin and at 4.2 Kelvin and these gases are dealt in next lecture. Let us talk about other cryogens like liquid methane. Liquid methane has a boiling point of 111.7 Kelvin it can be used as a rocket fuel and it is also being used as in the form of compressed natural gas or CNG. You know CNG is basically nothing but most of them is methane. One of the other usages of methane is in a mixed refrigerant cryocooler or in a cascade system one can use methane as one of the refrigerants in a cascade. So, you can have different temperatures or you can have different circuits where methane could be one of the refrigerants which can give you temperature between 110 to 120 Kelvin and then you can use different refrigerants with respective temperatures associated with them. So, these are liquid methane which is normally not very much used as such in cryogenic activities which normally is you know below 80 Kelvin as such, but it definitely forms one of the important constituents in cryogens. The next is liquid neon. Neon is a clear colorless liquid with a boiling point at 27.1 Kelvin. As you know it is a inert gas it is a very costly gas it is again a rare gas. Neon is commonly used in neon advertising you know this. Liquid neon is commercially used as cryogenic refrigerant. Sometimes neon is also used in the refrigerator as a pure gas, but again the cost considerations are plenty. It is a compact inert and comparative less expensive as compared to helium. If you compare the cost of neon as to helium it is relatively less expensive. The next important is liquid nitrogen which is very very widely used. It boils at 77.36 and freezes at 63.2 Kelvin. It resembles water in appearance and density of 807 kg per meter cube. This is very important. If I were to compare the density of nitrogen with water, water is 1000 kg per meter cube approximately. Well you can see it is around 807 kg per meter cube which is very comparable with water. And if you see liquid nitrogen it will be difficult for you to differentiate between liquid nitrogen and liquid and water, but you can differentiate it because of the fumes coming from liquid nitrogen. Because liquid nitrogen will be in a state of boil off the fumes will always be there. The vaporization will always be happening while it will not be true with water. And therefore, this is the only difference possibly one could come across unless you touch unless you put your finger in liquid nitrogen. But if you physically see liquid nitrogen it will resemble like water. Now nitrogen has got two stable isotopes N14 and N15. This atomic mass normally what we deliver is normally N14. Nitrogen 14 and the ratio of N14 to N15 is 10,000 to 38. You will have in universe around 10,000 N14 in comparison to that what you will find is only 38 nitrogen 15 isotopes. The heat of vaporization is 199.3 kilojoules. Again this is a latent heat we are talking about. So, if I were to get cooling effect at 77 Kelvin, what I will get from 1 kg of liquid nitrogen is 199.3 kilojoules. While if I compare the same with water it is an order of magnitude more for water which is 2257 2257 kilojoule per kg for water. And it is produced by distillation of liquid here. How do I get liquid nitrogen? So, biggest source of nitrogen is as you know air. Air we can assume to be composed of nitrogen and oxygen. And from air if I liquefy air then I can separate liquid nitrogen and liquid oxygen. From there I get nitrogen as a gas, oxygen as a gas. So, one has to do then fractional distillation of liquid air in order to get liquid nitrogen. Nitrogen is primarily used to provide an inert atmosphere in chemical and metallurgical industries. It is a non-reactive kind of a gas and therefore it is widely used because it is available in plenty and cheap. And therefore it is primarily used to provide an inert atmosphere in various chemical and metallurgical industries. It is also used to as a liquid to provide refrigeration. So, lot of activities related to food preservation or a blood preservation or medicine preservation one would use liquid nitrogen because it is cost effectiveness and availability and non-reactivity. It is safe to use liquid nitrogen in those places which gives you 77 Kelvin temperature and also gives you cooling effect. So, liquid nitrogen is widely used because of its availability and the cost for food preservation blood and for cells preservation. So, medicine as well as food industry liquid nitrogen have got tremendous usage in this industries. And importantly for high temperature superconductivity here one would love to use liquid nitrogen. One would hate to use liquid helium because liquid helium is very very costly. So, unless subjected unless required I would like always to use liquid nitrogen to get high TC or high temperature superconductivity. As I said earlier the research is going on in order to increase the temperature of various materials so that they can become superconducting at higher and higher temperatures. At moment I have got certain materials with requisite property and they showed superconductivity at liquid helium temperatures only. While if I were to use some materials at very high temperature of around liquid nitrogen temperature then I have to sacrifice some important properties that is the big problem right now. So, however I would always prefer to use liquid nitrogen as a temperature to gain superconductivity. So, research is always going on in order that I should get some materials with required properties to show superconductivity at liquid nitrogen temperatures. Lot of work is being going on in this area. Then comes LOX which is called as liquid oxygen. Liquid oxygen normally looks a blue in color due to long chains of O4. Different oxygen gets chain together and because of which you get a blue thing in their appearance. It has a boiling point of 90.18 Kelvin and a freezing point of 54.4 Kelvin. This again will be clear if one has a look at the TS diagram. All these properties are absolutely visible if one has a look at a TS diagram of this cryogens. It has got a density of 1141 kg per meter cube. Again if you compare with water the density of liquid oxygen is more than that of water. O2 is slightly magnetic and it exists in three stable isotopes O16, O17 and O18 in the ratios of 10,000 to 4 to 20. This is an information but what is most important? It is magnetic. Oxygen is magnetic and this property is utilized to separate something or to remove the magnetic materials from some area. So, this is a very typical characteristic of liquid oxygen or oxygen gas. Because of the unique properties of oxygen there is no substitute for oxygen in any of its usage. It is widely used in industries and for medical purpose. As I showed the whole of cryogenic engineering the first event was liquefaction of oxygen that means to reach 90 Kelvin and why did it happen? It happened because of its usage in industry as well as in medicine. One requires oxygen for leaving and therefore all the attempts were on in order to store oxygen in plenty and that can be done only in the liquid form. So, the research towards production of liquid oxygen was always on and this is what initiated in fact the whole of cryogenic engineering and as I just mentioned today collected and picked it liquefied oxygen in 1877 from where we have got the existence of LOX. It is largely used in iron and steel manufacturing industry. In fact wherever you have got a steel making plant liquid oxygen plant would be there. If the plant is if the steel manufacturing is in bigger quantity they can always afford a liquid oxygen plant on the campus instead of bringing liquid oxygen from other another site. So, this is a very important property of a steel manufacturing industry. As you know it is one of the oxidizer propellant for space craft rocket application. So, liquid oxygen is a very important oxidizer for in the rocket propulsion. As you know in cryogenic engine again liquid hydrogen is a fuel and liquid oxygen is an oxidizer. Liquid argon, liquid argon is also colorless inert and non-toxic gas. Again as you know these are all inert gases and therefore they are rare gases and therefore their costs are bit high as compared to other cryogens. Boil is at 87.3 Kelvin and freezes at 83.8 Kelvin. As I mentioned earlier one should see the only difference of 5 Kelvin between the boiling point and the freezing point. It is a density of 1394 as compared to water of 3000. So, we can see that it is a very dense liquid. It exists in three stabilisotopes 35, 38 and 40. The property of inertness of argon is used to purge molds in casting industry. Argon is very widely used in casting industry and also it is very widely used in steel industry. It is used in argon oxygen decarborization process in stainless steel industry and one of the important usage of argon is in welding. So, it offers inert atmosphere of our welding stainless steel, aluminum and titanium etc. This is what makes argon is a very important gas. The steel industry or the welding business runs on argon. As you know argon welding is very very popular for stainless steel. Argon has tremendous usage in industry both in manufacturing or steel industry or in casting industry. Liquid air. As you know liquid air is a mixture of various components, various gases 78 percent nitrogen, 21 percent oxygen, 1 percent argons and others means CO2, moisture etc. But therefore normally we can call it 79 percent nitrogen and 21 percent oxygen if we forget about these others. It has a boiling point of 78.9 Kelvin and a density of 874 kg per meter cube. Liquid air is was earlier used as a pre coolant for low temperature application and nowadays mostly liquid nitrogen is used as a pre coolant rather than liquid air. Previously liquid air was more prevalent to be used as pre coolant. Liquid air is primarily used in production of pure nitrogen, oxygen and rare gases. Now, this is a very important thing. Air liquefaction is a very big area, is a very big cryogenic industry and lot of air liquefies are still made. Because ultimately all these gases nitrogen, oxygen, helium, argon all these gases are coming from air and how do I get those gases? I get these gases only from air. So, what I have to do first is to liquefy air and separate out these gases of nitrogen, oxygen, argon, helium, carbon dioxide etc. by carrying fractional distillation of air. But for that what you need to have is a air liquefaction. So, what you need to have is a air liquefier and this is a very big industry and therefore liquid air is a very, very primary use cryogen I should say for producing other gases or producing other pure gases like nitrogen, oxygen and all other rare gases which basically you can find only in air. So, this is a one of the very important cryogen and also liquid nitrogen which are primarily used everywhere in cryogenic engineering. So, here I finish my second lecture and what I am going to offer you is a self assessment exercise after this slide. I hope you all would kindly and honestly go through this assessment exercise and assess yourself. It is basically check point for yourself. Whatever I have covered I just try to ask you some simple questions and you try to give the answers to those questions. The self assessment test has got some small little questions where is the blank given in every there are around eight questions. You please try to give answers and we feel that if you have understood what we have presented till now it should not be a problem for you to answer this simple question. It is a self assessment for yourselves right. The answers are also given at the end of this. This last slide gives the answers for this. So, it is a kind of check for your assessment. Thank you very much.


Before we get into the video guys, if you guys want to be in with a chance of winning this resurrectionist emblem, leave a like and tell me in that comments section what you're most looking forward to from Destiny 2. Can we reach 4000 likes? That'd be absolutely epic if we could. What's going on guys? Today I've been to another Destiny Top 5 plays and today we have Top 5 Lockies moments.  But let's get straight into it and in at number 5 we have a clip sent in by Adolphe's mom. I think that says, well this is how you finish a game. Oh my god. Oh my god. Oh my god. Oh my god. Please tell me I got that recorded. In at number 4 we have a clip sent in by Squishy Ninja. Now I have seen these hundreds of times in the past but they never ever get old. Damn. Did you see that? That was on a cross map. 3 we have a clip sent in by C's Clouds. Now this is what you call perfect copper flying. Or incredible. In at number 2 we have a clip sent in by the Reverend Tree 5. One bully, four kills. You can't really ask for much more. Three opponents down. This is amazing. In at number 1 we have a clip sent in by Elegant9618. Now this is beyond looking. Watch the whole thing but keep an eye out for what happens at the very, very end. Which clears their path to that lighthouse. I'm not sure if they have a run. Come here, come here. Watch if they have a run. Watch if they have a run. Watch the run. I'm covering you. Watch if they have a run. Yes, they have a run. Oh no, nothing more. Nothing more. I have a super run. Wait, let's wait a bit. Let's go. Let's go to the area. Yes, let's wait for the area. My guidance is very important here. That's what I was going to say. Yes, let's go to the area. Just where they are. How are we suffering? They're shooting at me. Damn it. Only 10 seconds left. Let's go, let's go, let's go. No, no, I still have a little left. No. It doesn't matter. If you can't kill them, capture the area. Guard, guard. Good, good. Ready, ready. The guy has a radiant.  Ready. The enemy was appearing again. Oh, what happened, what happened? The enemy? No, no, no. Well, well, whoever is there, whoever is there, whoever is there. No. They won, we won. We won. We won. We won, boys. We won. We won. We won. We won. We won.


For today's Monday makeup lesson, I'm going to show you how to create this purple smokey eye. It's a really easy look to recreate and you really only need about one brush and some purple shadows. Now to create this look, I'm using the Urban Decay Ultra Violet palette. This is part of the Naked Collection. I love this palette because they also have neutral shades as well as these beautiful purples. We're going to ignore the neutral shades for now and just stick to the purple shades but definitely let me know if you'd like me to create more looks using this palette. Before we get started with this look, if you're new here, make sure to hit the subscribe button below. It's totally free and we always start off by using an eyeshadow primer with every look but in particular when you are using purples, I find an eyeshadow primer really helps. It creates a blank canvas for us to work on and helps to make sure that those purple shades pop. We're actually going to start off with a very light kind of lavender shade and we're going to be applying this with a flat brush but you can use a blending brush. Totally up to you. You want to start by applying this above the lid so even kind of the crease area and higher but making sure to leave a small gap under the brush and I just like to stamp this along and then bring the shadow down but if you are using a blending brush, you just want to use it over and back in a sweeping motion. And then going to take this medium pinky purple shade which I think is one of my favorites from the palette. Again sticking with that same brush, I'm going to then apply this a little lower than the previous lavender shade. So still in the same area but just a little bit lower. What the lavender shade does is create a beautiful blend for this medium purpley kind of pinky shade. Again you can use a blending brush for this if you prefer. And then going to bring this down onto the lid and you want to very slowly build this up over time. Don't try to go in with too much shadow just let them build up slowly. And then taking the medium purple shade which is beside that and just applying this a little lower in the crease area and also onto the lid. Once again creating a fade from the purple to the pink to the lavender. And then I decided to use this kind of darker purple with a lot of shimmer. It went on really beautifully with my fingertips and sort of melted onto the lid. So I would suggest using your fingertips or a flat brush. And then applied a little bit more of that purple shade and just apply this underneath the eyes using the same brush. Now I used a black liner on my upper and lower waterline but that is totally optional. You could just leave it blank or use a nude or even using a purple just to bring the look together. I finished off with lots of mascara and some lashes and that is the finished look. I really hope that you guys enjoyed this one. If you did, definitely let me know by giving the video a thumbs up or a comment. You can also come over to Instagram, Facebook and Twitter. It's at Shnady Katie but you really don't have to do that. I just have to kind of say it here on YouTube land. Definitely check out some of the other videos on the screen though and I will check back with you guys next Monday. Until then stay safe and I will see you guys in the video really soon.


Thank you guys. Thank you for a movie here and I'm so happy to see a lot of people at the panel And thank you for our guests. I'll just introduce their name and then we'll have a lightning Discussion with each of them four or five minute each. We want to make sure we time in them with signals So okay, I'll keep it short because then the fun part is the panel. We have a nice discussion We have an interesting background from operation business development And also the software development so a nice panel and also what I'm very pleased that you know This planet is around the world from New Zealand to UK to Italy So we have basically all the continent a kind of kind of all the continent. I'm just missing Asia next time. All right Thank you I'll do it before the do I'll introduce the name and then eventually you come over and you have your own presentation Flavio Fazzano Bank in Tessa, Italy Roger Donaldson Bank on New Zealand Steve O'Day Clicedale Bank and I mean from Nordia Bank and Hernan Zitz Felipe from something there's some tech. Thank you First of all, let me just I'm very very honored actually to do a quick update to all of you I think is something to do probably a week ago if not to The clicker is here. Perfect There you go. So I just want to mention something a new newly formed the organization Finos is Probably the first time ever that we have an open community foundation that only is only dedicated to financial services and Open source so many banks are now finally joining to Contribute into the open source. What is all about Finos is a great idea is United the open source community and the financial service community to start together to collaborate on creating Solution for our financial services as you know, historically bank had been consuming open source for quite a while probably a couple decades Probably the biggest open source project that they consume its Linux, right? And also the variation of Linus being the redette Enterprise Linux supported version But more over there are many other body of code that are being present at your banks I'm sure you guys using Tomcat. You're using a dupe and many other open source So this is Finos is finally the joint venture between FinTech and FinServe I like very much that you know that the the new Entrance to the financial service units are meeting the banks into a community to really Organize themselves and share code and solutions So if you see a lot of very interesting members from the financial service community very top tier banking But also financial service and technology services joining the community a lot of a Project being launched and more to come and here is actually an invite to you to join the To join the community, right? It's an open source community, but it's led by Requirements and by use cases driven by the top banks very interesting opportunity and redette has been asked to join and thank you to to Finos executive director, which is here if you guys want to know more Gabiele and Peter The executive directors are here if you want to know more they can explain more about the community What is in this you why I brought it up because we just launched two weeks ago together and the open shift is the foundation of the Finos open development platform so we are very proud that the community is using the technology that you guys are expert in and Many banks have been already contributing to share their code with Deutsche Bank for example that offered to major projects here and I'm gonna go and jump into the banks


In this video series, we will use Pixie to estimate the cost of our Kubernetes services. We will be calculating CPU, memory, and network costs for our services. In the last video, we'll compute the amortized costs per request for each service. Pixie is an open-source observability tool for Kubernetes applications. Pixie uses EBPF to automatically collect a lot of data out of the box, such as infrastructure and network metrics, application profiles, and full-body requests. Pixie is a scriptable interface, so you can modify existing scripts or write custom scripts to do the analysis that you're interested in. In this video, we will be writing a custom script to get visibility into the cost of our services. In this first video, we will focus on CPU cost. CPU costs can be calculated by multiplying the amount of time the CPU has been utilized, times the number of CPU units, times the price per CPU hour. So I've got Pixie's live UI open, and from this HTTP service map, you can see all the microsurfaces that are talking to each other. I'm going to open the scratchpad script. I have the custom CPU cost script pasted into the editor. Let's run this custom script using the run button, and here we can see two tables that this script is outputting. The first table shows CPU costs broken down by service, and you can sort that. This first row, which doesn't have any service listed, is CPU costs associated with pods that don't have a service. The bottom table sums the CPU service costs into a total cost. So let's open this script using this script editor button, and take a closer look. So this script loads the last one hour of Pixie's process stats table into a data frame. The process stats table includes CPU usage for all of the Kubernetes processes in your cluster. CPU time is measured by a counter for each UPID. So to figure out how much CPU time each service spent in the last hour, we take the min and max of each counter to get the CPU usage over our time window. Then we sum the CPU time for all UPIDs per service. This CPU time is in nanoseconds, so we convert it to CPU hours, and then we multiply that by the CPU cost per hour. Note that the hourly CPU cost will vary depending on your provider. We've chosen an estimated value, but you can try the script out with your own value. We then multiply the hourly CPU cost by the number of hours in a year in order to estimate the yearly cost of that pod. All of these scripts are public, so you can try them out by following the link in the video description. If you want to play around with this script, it should be easy to modify it to slice cost by name, space, or pod. In the next video, we'll do a similar analysis for memory usage, so be sure to check that out.