Welcome, welcome, welcome, good evening everyone for our official welcome to our December story-telling showcase here at McKinnon's Institute. My name is Alyssa Stone, I'm the Senior Director of Programs and Community Engagement here at McKinnon's Institute, and I'm so excited to welcome all of you fabulous faces for this pollinating show. Who here has been to McKinnon's Institute before? Awesome. Who is here for the very first time? Oh, you've been to many visits to our historic building here at McKinnon's Institute. For those who are less familiar with us, McKinnon's Institute was founded in 1854, so we are a very old nonprofit here in San Francisco.  If you haven't checked out the library on the 10th and 3rd floors, please do so. It's beautiful. A world-renowned chess program here in the oldest chess club in the United States, and an event center like we're doing this evening. We have anywhere from 5 to 15 events per week here at McKinnon's Institute. Everything from story-telling showcases, author talks, books, rooms, writing classes, chess classes and tournaments, and all manner of things that you might be interested in. Please come and check out what we have to offer here by visiting mhinelibrary.org. We also offer a free Wednesday tour, every Wednesday at noon, and we have an evening tour coming up on Friday, January 25th at 5 p.m., so if it's been a while or you haven't had a chance to explore our incredible building, please come back for one of our tours. It's a wonderful way of learning about our history and our services and seeing all the different interest-based notes and crannies here at McKinnon's Institute. I'd also love to invite you back for some of our upcoming programs in January. This is somewhat our finale of our month of our year of 2023 and what a way to end it, but I'd love for you to turn your mind towards January events. Our Cinella series in January, Cinella Lit, is all about chess in the movie. So every Friday in January, come and watch a movie here or join us for an online discussion where we'll be showing our first film on January 5th, Cinella Lit. So it's a really exciting theme in January. We also have a brand-new program starting on January 9th, our digital connections program. So if you are someone who would like to explore more digital tech-savvy skills, our digital connections program is like for you. And we have our first author talk of the year on January 11th, where we have our second annual New Year Wellness and Renewal program. So we have a lot of fabulous things coming up at McKinnon's Institute. I hope you'll be back. And I'd love to introduce our incredible host for the evening, Corey Rosen, who is a producer and story-selling teacher based in San Francisco. He hosts the Moth Story Slams and Grand Slams and has a feature on the Moth Radio Hour, Alan's Radios, the Sarah & Vinnie Show, and K-pop The Fitch Files podcast. Corey is a performer at Fats Improv, one of the world's foremost centers for improvisational theater, and is the author of The Door Story, Well Told. Creative strategies to develop and perform stories that one-hour audience. He always files us here at McKinnon's Institute. I hope if you're not yet a super fan of Corey Rosen after tonight and hopefully should be, please give a warm welcome to Corey Rosen. I'm proud to be doing this news since many months now. Make that happen? Okay, so I think we should do this in September. So here's the concept. Oh, in May? Who's in May? Our first one was in May. Well, we haven't been doing it all summer. We took a little break though. We took a break. So we did one in May. And then I had to ask if I would come back and do basically once a month. So this is a monthly series of storytelling. And so what we do is every month I invite different cohorts of people and it's kind of become, for me personally, a glimpse into all of the aspects of what I like to call my lives, not just my life, but like different parts of my life. In the first month of the show, we had a lot of people that were involved in the mock, which I have a host of. In October, we did nothing because COVID was my life that month. So we did nothing. In November, I have some friends who run a show in New Portland called Backpack PDX, which is basically a random storytelling show involving us spinning wheels. Anybody here for that show? Yeah. Where the storytellers didn't know what story they were going to be telling. So it was storytellers basically being spontaneous in the moment and telling stories. So we had that whistic. Of course, when I was telling a story in that one, we had Casey Clemm who was DJing in that one. We did not like that there was a DJ for that one. It was very loud. So we are having no DJs in that one. Now it's December and because of October, we're bringing back the October storytellers. So let's hear from the storytellers tonight. We've been waiting for two months to tell them stories. So the people that are going to be telling stories tonight represent for me a range of people from my, as I mentioned, my lives. Me personally, I've worked in my career in various places, both in the theater, storytelling, and film production. So what I have done tonight is I've invited people from many of those aspects of my lives, both my theater life, performance world, and my film world, specifically in animation and visual effects, with the props tonight of behind the scenes. So all of the stories in some way will be connected to a behind the scenes scene. And they may or may not, because I remember this was originally the October, they may or may not be behind the scenes horror stories. They may not be, but they may be. Or they may not be. That's what they or may not part of that is that they may not. Or they may. So you understand the rules of that. So don't be disappointed or offended. Calibrate your appointment meter based on that. So that's what's going to happen. We're each going to be somewhere in the range of five to ten minutes in the storytelling, and the whole show will be over an hour, right? It's not bad for a Wednesday night, right? But here's what I want to do. I'm kind of calling it audible. Sometimes I like to do this. People seem like nice people. And some of you have commented people that you know, some of you have not come with people that you know. Sometimes I like to start the show by having the audience tell stories to each other. Are you paying for that? If you're not, you don't have to. But here's what we're going to do. For exactly one minute, each of you in the audience, I'm going to invite you to turn to somebody near you and I encourage you to not talk to someone that you know. It could be somebody that you know or somebody that you don't know. But I'm going to say if you came with someone and you want to tiptoe out of your comfort zone, turn to the other way and encourage them to do that. You don't have to. You can talk to your friend or you can talk to your cell phone. You can even calibrate your experience however you want. But here's what I'm going to ask you to do. And it's going to be a very interesting exercise I think for some of you is that the challenge is to tell a version of your life story in one minute.  So think about a version of your life story. Maybe your love life story. Maybe your geographic life story. Maybe your academic career. Maybe it's your pet life story. The pets that you, something that's just like narrow the scope to a topic until that life story in one minute to somebody near you.  So figure out if there's somebody that you know, it's still a good challenge for somebody that you know. And when I say start, you're going to tell a real life story in one minute. Does anybody need a partner? Raise your hand if you need a partner. Ready? I'm going to start the timer. I'm glad we came up with it. Anybody need a partner? Raise your hand if you want a partner. We have one person for you to be my partner. Come on over here. Okay, ready to begin? And begin now. That first one is going to take about a second. Okay, ready to start? The other person has a minute. Tell a version of your life story in one minute. And begin now. Are you ready to start? There's everybody. So I'm going to tell a personal behind-the-scenes story of my environment. I'm going to start to get to our first storyteller now. I'm going to invite to the stage one of my dearest friends of New Yorkers who I'm just thrilled to know and to welcome to the stage. She professionally works at Pixar Animation Studios and her name is Lila Cheswell. Please welcome her. Is this the first birthday party? It's my birthday's in four days and I've lost a quarry of birthday parties to them and it was the best day of the year at Island. So when I started there back in 1996, I was pretty much just having an college right there and all I wanted to do was write from that was it. That was my goal. I was like, I want to write from there.  And I had a little apartment in San Francisco. It was like $300 a month rent to share a little apartment underneath someone's house out of the avenue. So it was really awesome. So I took a job at this place, Island. I'd never heard of it. I didn't know what it did. I didn't know what anyone did there. But one of my friends from Infraud, she said, oh, I work there. You don't want to work there. I said to my mom, I know you have a connection there. Thank you very much. But my friend said I didn't want to work there. And my mom said, what have you got better to do? I took the job. So I took the job as a administrative assistant to the technical assistance. I had no idea what they did, but I said, okay, what's my job? So this woman, Wendy Hendrickson, remember, she says to me, okay, this is what our job is. You're taking over for me. All you have to do is walk around and just post things on the walls and talk to people. And there's a mat underneath the desk. You can sleep there. Crazy. So I said, I'm not doing this. So I walked around and I said, okay, well, the technical assistance are very easy to see. So I started talking to them and my two graduates and computer science, their Stanford PhDs, all these people, I want you to know, you're amazing. He was my teacher-husband. He's amazing. I was in awe. So I said, I want to do what they're doing. So they started training me. She needs to go and sell it like this. This is incredible what you do. I can do this.  What are you crazy? You're crazy. You can't do that. You're an English major. You don't, this isn't, you don't, I might decrat this somewhere. I just sort of started following along. What are these guys doing? Learn from them. Learn from them. I mean, I was learning what I found out from the best of the best, right. So this is guy, you know, Kurt. So he gets me on a show as an assistant technical director. I'm like, okay, this is great. I'm loving this. I'm doing whatever they tell me to do. He says, write a script to compress texture. I'm like, okay. I'm like, I did this, right? I learned scripting. I learned all this stuff. Compressing textures. Okay. So I go to my machine. I write a script. I'm good at learning. You can teach that very teachable. Okay. So I write this script.  I'm going to go for a bowl of lunch. But lunch is nice. Lunch. You gotta be close. Have lunch at Iowa. It's like, nature's a beer. It's an amazing thing. You should do a spring frog. Okay. That's his story to tell. Okay. So we had a lot of fun in previous lunches. I come back and I know this. My machine is just sort of hanging and some people were just going on. And somebody said, ooh, it's like your machine is swapping. Okay. My machine is swapping. I knew that wasn't a good thing. Okay. Suddenly we're getting error messages. A lot of error messages. My machine goes down. Okay. So I remove my machine. I have to go to Kurt.  This is cool. And I say, listen, Kurt, I had my machine swapping. I wrote this script to write, to compress textures that was going. It was talking along. And now it's my machine work. And I think it goes, what did you keep along by? That's a great idea. I will totally keep along by the next time that I do this. I remember. So he totally, no problem. I feel out of it. My machine comes back up. I feel out of it. I'm like, okay, restore backups. Because there are hundreds and hundreds of gigs of corrupt textures at this total out of Friday afternoon. So no vendors are going through. Everything is broken. The entire facility. That's how I feel. Star Wars episode one. There is no Jar Jar Vegas right now. Okay. So what happens? This is the moment we realize. And I put in this request that the backup system or all the backups go longer. And they haven't been working for the past four months. They switched to a new system. So Kurt looks at me. Mr. Bass on all seriousness. It goes, well, yes, we're going to make new textures now. Doesn't give me any grief. We just go through. So in textures, no problem. We're doing all this work, everything. At the end of this, he says to me, ladle, we learn two things here, right? One, we're going to keep a log file. The backup system doesn't work right now. You know what I did in return for Kurt, Mr. NASA? I'm introduced into my childhood best friend, Sara. She's a dentist. And they are married with two children now. So go down, go down, my friend. It's right. It's like making up stories and in the moment. So one of the things that we were trying to do physically, because when we worked at Island together, we were very sedentary.  It was also the age where we discovered carpal tunnel syndrome. You're literally not moving. You're moving your wrists all day, and things are very painful. So we discovered there was a nearby gym to where we worked, which was across the Richmond Ridge. You're in San Rafael to Richmond, California. There's a big municipal mandatory called Plunge. Any fans? Yes. And so by then, I also did improv theater together. So one of the things that we would do is we would swim across the pool. We would do laps, and we would surface out of the pool. Lila would say, once. And then we would swim entirely across the pool every one month. And I would say, then upon, we would tell a more than a time story, the pace that it would take to go entirely across the pool. So every lap was a word. So you would be like wondering, so it wasn't like the spontaneity of improv, where you were like really in the moment. You had like those 30 seconds to then you would deliver the next word. And it was so satisfying whenever that word was, because you weren't getting a word every minute or so. So next time you're swimming with a friend, if you want to tell a very slow story, I highly recommend that you tell like maybe like a 25 word story. All right, are you ready for your next story? Tell us. We're going to mine from the world of ILM and movies who also have just own rich history in so many aspects from Clown College in Florida to a recent in the circus to working at Universal Studios Hollywood, creating makeup and masks and creating creatures themselves. Please welcome to the stage my good friend, Mark Siegel. So this isn't behind the scenes story, but and so it's kind of funny, I vote. But part of it, because it was originally scheduled around Halloween, is a bit of a horror story, in particular for one of the crew members. And it doesn't involve ghosts. Really not in my creature making career while I was still working in LA. I have been fortunate to be hired on the crew of the original Ghost Busters at the Boston Richard Edlins Company in Burrida, Del Ray. And my main assignment would be to work on the puppet for the Ghost Slammer. And when I was hired, Slammer was already in progress. Our creature supervisor, Steve Johnson, had already finalized the design when I showed up for work. On my first day, Steve was already sculpting the main head and body section of what would be the puppet suit. Another artist, Kevin Brennan, was sculpting Slammer's arms. And my first project would be to sculpt the inner parts of Slammer's mouth, the teeth and gums, and the tongue. So we took a casting of my arm in hand. And I did the tongue sculpture over that casting. And so the final rubber tongue would fit my arm perfectly, perfectly. And then I would be the puppeteer whenever the tongue had to work in the shot. Well, as it turned out, the tongue would only need puppeteering for one shot. But this was a really important one. It was the first time the character appeared close up on the screen in the scene where Dan Akra discovers Slammer in the hotel hallway, gobbling up food from plates on a room surface. And it was a pretty tricky shot to get. And I'm going to try to describe to you how we accomplished that shot, which is pretty ingenious and kind of fine. But first, before I try to do that, I want to give you a description of how the puppet was constructed and generally how it worked. And you probably know us by now visually. Slammer was overall a very low-tech puppet. It was one big piece of MMI section that was cast out of a very soft foam latex rocker. Mark Bryan Wilson was the lead puppeteer who bore the puppet suit and he was strapped in with the kind of harness made out of a light webbing. His arms were in the rubber Slammer arms that stuck out through the cobbles in the side of the body. And Mark would do all the big body and arm sort of here. The bottom of the puppet came down from above Mark's waist. Below that he had a long black skirt and we got on the black stage so all the on-camera puppeteers were flat. The top of the puppet came up above Mark's head. Now because it was all soft foam latex, we had a fiberglass understall inside that head so the head would hold its shape. And that understalled me attached Slammer's eyes and the rubber palate with the gum to the teeth that I had created. And we also attached a few controllers for facial expressions. Now Mark's head was tightly secured in a custom-spit fiberglass helmet that we could attach into that understall. So that Mark's head would support the top of the puppet. And Mark's face, this is the really important part, Mark's face was directly behind Slammer's big mouth and we got holes in the rubber at the back of the throat covered them with a thin scrim fabric, same color as the interior of the mouth so that the camera couldn't see in but Mark could see out through the mouth in order to work. Now the facial expressions were also pretty low-tech. This was a few years before we started using radio-controlled methods and it was simple bicycle cable controllers. And the cables extended from the head down through the bottom of the puppet out to the side connected to controllers with levers. And puppeteers would pull the levers through the different expressions. We could move Slammer's eyes back and forth. We could blink his eyelids, pop his eyes out a little bit, wiggle his nose, mirror his upper lips, and move his eyebrows. And for the shots when I didn't have the puppeteer at the top, I was lucky I got to choose my puppeteering features. And I chose the eyebrows because I saw the most potential for a big comical eyebrow. The mouth was also extremely low-tech. There was no structure or mechanism at all in the lower jaw. It was just soft foam latex. We didn't have the plastic gums and teeth mounted inside the mouth. And then just a little metal bar in the center of the lower lip with a rod that extended down through the bottom of the puppet. And the puppeteer underneath for Kate and could pull the rod so we could stretch that now really wide open or push it closed or twist it side to side to give a wide range expressions. And for most of the shots, or all the shots actually where the tongue didn't work, we had a casting of the tongue that was just cast inside the mouth and could just walk around. But that eating shot, the Slammer actually had to use the tongue of that, got a little more complicated. So this is the setup. On the shooting stage, we had one of the metal rolling stage equipment cards that served as a stand-in for the room service card. It was stacked with all kinds of plates. Some of them were made out of plaster so that they could break easily. And the plates were piled with all kinds of nasty food. We had like wilted lettuce and chunks of jello and lots of mashed potatoes and pasta, some half-eaten slices of pizza, theory rolls and other chunks of bread. And Slammer would have to reach out and pick up the plate and dump the food into his mouth from the jaw and have to work on the tongue. Move around. So because I had to operate the tongue with my arm, I had to be squeezed in when really tightening behind the pocket with my arm in the rubber tongue through the slit in the back of Slammer's head into the mouth. Remember, that's where Mark Bryan Wilson's head normally was. In order to make room for the tongue, our hand was bent the same way down below the mouth, so my arm and the tongue streamed sitting on the top of Mark's head. Also, because he was bent over, he couldn't be in his helmet as he'd already was. So Steve Johnson, our team leader, was squeezed in right behind me, intimately behind me, with his arms in, and his cheeks. I didn't support the head down, but he also used his fists to march the rubber cheeks around like to give some more movement to the jaw. But most important, because he was bent down, Mark could not look out through the back of the mouth as he normally could. Mark was working completely blind, and working blind, he had to somehow, finally, lift it way over his head, dump the food into his mouth, throw it all over the tongue while I'm working the tongue, and make the tongue slip. And that meant that Mark was actually dumping all of his food into the back of his own head. Despite all of this, bent over, blind, food all over him, Mark did a stellar performance. He even added nuanced movements, like slimmer, casually tossing an empty plate over his shoulder, or lifting up his hand to wipe his mouth between bites.  Everybody except Mark Grand Wilson, who was still stuck bent over in the puppet, which was not easy to get in and out with food all over him. After a few moments, we heard this muffled voice coming out of this rubber puppet, get me out of here. Which of course made us crack up even more. And even though he was very low tech, I think Slanger did a wonderful on-screen performance. He was very funny. And as some of us actually predicted while we were shooting the puppet, Slanger became a really popular character. He even got his own animated cartoon show, and reappeared in Ghostbusters 2. I just have to say that in my nearly 40 years as a creature maker, working on the original Ghostbusters was some of the most fun I've ever had, working on a TV. One more time for Mark Siegel! Congratulations for Range Eller. I love it every time I see you. And are you still ever at Walt Disney Family Museum? I go as often as I can. I volunteer there. Since COVID, they cut back a lot of the time. I volunteer for special events. Have you ever seen Mark? You're ever at the Walt Disney Family Museum, because he has full loads of Disney spaces. Thank you so much for sharing that with us, and we will move along to another. This is like a tour of my favorite people in the world. The next storyteller is one of the first people that I met when I moved to the Bay Area. I was a college student still at the time. I was an intern, and I became fast friends with him maybe two short years later, less. We were roommates for 10 years. So this is someone who I know a lot about and have a deep, deep history. He is honestly one of my truly best friends in the world, and he is himself incredibly gifted and talented designer. They'll make her a storyteller in every sense of the word, and I'm not going to tell too much. You're going to hear from him the words of George Hall. Give it up for George Hall! Just a moment around, but I don't think we ever have any. My story starts off, I'm 20 years old, early 20s, and I find myself, I get to my dream, and my first big opportunity is to become the Visual Effects Director, and I'm assigned to work on the movie Mission Impossible. I got this. This is amazing. I finally got to the big times, and I find myself invited to fly to London to a meeting with Tom Cruise, Brian De Palma, and the visual effects supervisor of my boss, John Null, who's famous himself for inventing this small program called Photoshop. So this is like the big shots, and I'm literally only there to draw some images to help these big guys figure out an action sequence. So in this script, there's, service can be like, and then a battle ensues, and I just leave it and they later figure out later. So in this script, there's an action sequence where Tom Cruise is our big guy, there's a train on top of a train with a bad guy, and there's a bad guy in a helicopter machine, and they know that they want this action sequence, the train, to go into the channel from home between England and France, and this helicopter to be chasing after Tom, and there's going to be this explosion and crash, and Tom just nearly escapes death with this helicopter to stop, but they can't figure out why a helicopter would ever go inside a tunnel. So we're at this meeting, you know, it's a gorgeous hotel, and is this exclusive, and you know, a couple hours go by and they're taking around ideas, and all of a sudden Tom goes, does anyone have ideas? And in my head, I feel like this excitement like surges through my things, like see my like success montage going through my head. I say this genius idea, everyone's like, who is this guy? They're like, maybe they need to talk to directors, and I'm going to cover a time magazine, and I'm like, all of a sudden, I'm thinking about this, I've thought of zero ideas, and then Tom goes, yeah, I've got it, and I'm like, oh, shit, I have the money. I got it, I got it. The train is racing to the tunnel, racing, racing, racing, and the helicopters are behind them, and at the last minute of the train, you know, the train goes in the tunnel, at the last minute of the helicopter, there's nowhere to go, it pulls up, I've seen the helicopter, it does this giant loop-to-loop, at the end of the loop, it has nowhere to go but into the tunnel, and I'm like, I'm so jacked up to say my great idea, I can say the first thing comes to mind, and that is, well, that doesn't make any sense, Tom. I see my boss looking at me with big eyes, I didn't see Brian Paul looking at me because he's playing it for a long time. There was a reason why no one said anything during that time, because he's the commander of the show, and I'm like, I think to myself, did I see that allow? Why have I been going with this? I'm like, well, you know, why would a loop out there at the end of the loop go inside to stay on the trajectory and go in the tunnel? I'm like, what is a loop-to-loop? I mean, isn't that just a loop? I mean, I'm lying to my boss and I'm like, he's getting in the eyes, I'm like, stop talking, because to Tom's credit goes, the kid's got a point, let's keep working on this. So what happens in the film is that Tom, you eventually come up with Tom, puts this table onto the train and forces it into the tunnel, and you know, there's not too many of them in the movie, you know, he's on the nose of the train and the helicopter crashes and the plane just barely comes into the tunnel. But I think that I think to myself sometimes that if it wasn't for me opening my big mouth, there would be a giant loop-to-loop. And that was Tom George's last helicopter movie. Jordan also, I can now brag, designed, if any of you is a fan of the new June movie, the Hornetopter helicopter. Yeah, George, if you got your leg up. It comes out in February. All right, thank you, George. And let's move on with your tour acts. Our next one is also about your, it's only favorite people.  We do this every month. It is always, always the last Wednesday of the month, except right now, which is not the last idea of the month. But our next show will be the last Wednesday in January, which is actually the last day of January the 31st. I've invited another group of my favorite people. The theme of that show will be pets. Pets. They will all be pet stories. And you can probably tell them that I'm running out of ideas. I want to encourage also everybody, if you have an idea for upcoming show to visit my website, which is just quarryrozen.com, where I'm social media story Rosen. Tell me what to do. Tell me about the great show you would be interested in seeing and coming back for, please. All right, so moving on with the show. Our next storyteller is a happy city among many incredible accomplishments in his life. It's one of the founders of Bats Improv. Bats Improv, which is the longest, most successful theater or improv theater company in San Francisco, not the West Coast. One of the co-founders of Bats Improv. And now still in it's, what are we, 30? No, no. Seven. Seventh year. 37. 37th year of doing the improv theater. Bats Improv is located in Fort Mason Center, where everybody can do live improvised shows. He's also a stage actor. He's also an incredible teacher and performer and runs a company called Fratelli Foclonia. Anybody who's a fan of their incredible work? I'm going to say less and just let him do the talking. So please welcome to the stage, William, a lot of unwelcome sometimes. Can make all of it. My father was a physical surgeon. He was obviously a physical surgeon, but before that he was an advertising man. He said that in his passport, he was advertising. He told me the story of that transition. He said, Bill, I work from an ad agency, and they gave me this thing to count to work on. I did marketing research. It was a big deal. That's the massive deal. I had to do marketing research for douche. Yeah. He said, you know, they didn't understand why they wanted what they think it is. So that program, that's the last project of the year. The client, they over. The boss, congratulations. Great work, Bob. Fantastic work. I've got to do a client for you and a product. Enema. In that moment, it was crystal clear like that, that there are better reasons to stay awake at night to remember what color to make enema, to make what we do look like. So he left that job, went back to school, became a physical surgeon. One summer, years later, or was there, he was the director of a summer camp in the Shenandoah Valley. If you've been to the Shenandoah Valley, this is for marketing review. It's just so rural. It's just so nestled in this valley. So he understood. I mean, it's just beautiful. New York, way out. Well, he then decided that he was going to take all the units, that 13 people, four of them in the property, for a canoe trip down the Cleveland River in West Virginia. Nine canoes, big man, couple of them, a kayak and an older guy. 16. My mom too. So we're unloading the canoes, getting into the water, draining a little bit. We're kids. We're going to camp out on the river. We're going to camp out. We're singing our songs, paddling. It's just beautiful. It's just Western Virginia. It's incredible. As nice as the Shenandoah Valley is, this is untouched. You're not seeing any houses. We're canoeing along. It's just beautiful. It's just gorgeous. We're like giddy. We're out here on our own. Of course, it's raining, but that's not going to be you. We set up camp that night, set up our tents in the new rain, and we'll keep there in the rain. Sleep in the rain in the morning, raining, so we would have us in the rain. So it's just so beautiful. We're just so excited to be there on our own. It's all right. It's all raisins and peanuts. Yeah, okay. Yeah, it rains that day, and we camp in the rain, set up camp in the rain. We sleep in the rain in the rain, in the rain, up in the rain in the morning. Everything, everything is wet. We're paddling long, and it's no longer like, look at this beautiful stuff, because I've been in this business going to stop me. So something snapped at me, and I looked at it next to my dad. I found it next to my dad, and I looked at it, and all the seriousness, like a 14-year-old boy came and mustered it. I looked at it, and I said, Dad, this isn't funny anymore. Come on, yeah. Never want to even miss a moment. It's a deep breath. It's the constant balance right there. He puts that in, and he says, in his beautiful quiet tone, he says, what would you like me to do? In that moment, he left me here. I was an adult. I was an older kid. He just opened the door, everything changed. Everything changed, and now the daddy couldn't fix it. Well, we were all pretty wet. We found, we were living for a place of care at night, because we didn't pass any house. They said it was rural. We played nowhere. I wanted to do rapids and stuff. Finally, we find, like, this hill, uphill, uphill, about eight feet. Then it sees this stone standing roof, four posts, a concrete slab, and a roof. So we came there. Again, argues with himself about whether or not to use the wood, because it's not ours, because it's this thing. And he decides, oh, yeah, we can use the wood. Yeah, fire at night. Tent, no purpose, putting those up. So we put out our sleeping bags. We're all on this concrete slab, at least of the rain. I wake up the first thing in the morning, like, see how wet. I open my eyes. I go, there's water. Hey, everybody, look, look, there's water. Look around. There's water all around. I look over where the river is, and I don't see a river. I don't see a bank. I just see the flowing water. The water's come out that hot. Oh, God. Oh, the guys, guys. Oh, brother. There's a learning thing. And my dad comes and he says, Art, Bill, you and Tim, I want you to go find the talent. The little talent, I think it's happening. Paul will camp, set the van, then come back and find us. Meet us where you are. We'll get out. Now, I'm an adult. I run into the woods with this old boy, and we're like, you know, we're going to find this big man. We're going to leave the backyards. I hope we get close to a town. Find the town, little town. Not really even a town. It's unimportant. It's nothing, but a couple of shops. We phone them, and we'll meet you there. Send them in. We go back and find the, find the dad and the kids, mom. We leave them through the woods back to the backyard, into the town, into the bridge. You see the man on the other side of the bridge. The bridge is covered in water, because the water is overflowed with banks, and it's rushing past. And we see trees and stuff, but I mean, it's like, it's like a thing. Again, there's this thing where he's, Lock-oners! He goes, I'll get it. No, you won't! He made it across. We get into the van, we go back to the camp, get in the fresh, warm, dry clothing. We have a nice meal. We can calm down, come back to who we are. It just doesn't experience it happen to us. It was a day later, the sunshine was out. It's like it never happened. Our bodies are full, but it's like, like something that happened to us. It's not real. Sunshine! Dad said, we've got to go back. Dad, why? The canoes. We've got to find those canoes. They weren't ours. All right, Dad. Get in the gas car and drive back there. Make our way through the backyards, up into the woods. As we get into the woods, my mom and my dad and I, the cloud passes over. We're walking. Temperature drops a little bit. Wind picks up.  And I remember the three of us stopping. I don't remember us talking very much. So I remember the three of us looking at each other, going, turn around and walk back in the car. We all talked about it a little bit later.  That happens not on stage, but behind the scenes. These big moments that change everything. But those moments can give us a crystal clear vision of how the world works. It changes in an instant. For that reason, I hope you all have these unwelcome, unplanned, horrible things happening. It's kind of on the theme that we've been talking about. You've heard a number of stories about people in the film industry, in the visual effects industry, and mine is similar to that vein. Something that I was always impressed with in the special effects and visual effects, tension and detail. Like having an incredible eye and training that eye to spot even the smallest imperfections in everything. When I started in this business, I was very young. I didn't know much about it. In fact, I had the fortune to start at the company that people talk about, that's what I imagine, right at this transition period where things were becoming a little less of the handmade, painted, crafted, puppeted creatures and starting to develop into the digital realm of computer graphics and animation. What that meant is that since we were still shooting everything on film, there was this analog to digital handoff that had to happen. All the film would scan into the computer and then hand it to the computer graphics department. Along the way, they discovered that the film was imperfect, that things were not right. As a company that valued itself on tension and detail, a department emerged from this that I, being a very junior at least person in this field, found myself in the good fortune to be hired as a dirt remover. A dirt remover. Yes, the lofty position of the digital version of Enchanter, that I would look at each frame of the film and scan it for little imperfections. Now this might be a scratch or a smudge or a dirt that had gotten on the negative, but when it got scanned, it would create a little white pop on the screen. In order to do this, we used a program that was like a photo version of Photoshop, and you would look at one frame at a time, and you would scan through it, an incredible zoomed in. You would scan through the film until you saw something that looked like it didn't belong there. And then you would beat it out and move along. Just like when you next save your table, it doesn't use a lot of your brain to do the same process. So I would listen to a lot of books on tape. I would listen to a lot of music. I was occupying my brain otherwise while I was in the other side of the scanning through this in the glorious film industry, cleaning film one frame at a time. And the first project that I was brought onto this process for was a remarkable one. It was the movie that kind of made me want to be in the entertainment industry in the first place. It was the special edition of Star Wars. So I got to work on Star Wars, a movie that came out when I was a child. Now I'm working as a professional being paid to clean Star Wars. One dot at a time. And one of the first shots that I got to do this on, a star field. I'm not kidding. A frame of film with nothing but white dots. To determine which white dots did not belong, which did, was a very important position. I framed my frame to eliminate all of the white dots. My next shot after I got through the star field sequence was, and it was a very important shot. It was a really shot of the movie where the star destroyer is kind of chasing him. It was very exciting. But the next shot that I got to work on was even more exciting than me because it was a shot that had been eliminated from the original movie was being added in. Added back into the special edition of Star Wars, which was a scene, a deleted scene between Han Solo and, yes, Jabba the Hutt. Jabba the Hutt, the famous, you know, bad guy of Halloween who was talked about but never seen until Return of the Jedi. And now we're actually going to see Jabba the Hutt in a piece of film that was filmed back in the 70s with a very probably angry actor who was in the biggest movie of all time and was cut from the film, right? He was this Irish actor who was wearing kind of like a big brown trunet, kind of like a toga, do you remember that song? Yeah. And so he was filmed and he had this whole scene that was eliminated from the movie. And then later when his character showed up, he was simply replaced by a giant slug, of course, under the hood of Jabba the Hutt. So my job was to clean that scene. And of course, we're going to replace this guy with the slug again, computer graphics. And so I'm going through it. I'm listening to my books on tape and I'm listening to the things and I come to like a little piece of white, done. I remove it and I keep going and I'm going through until I've removed all of the dirt. And then I go to this little view station. And we would play it back and I noticed in my shot I'm looking, I'm scanning it for little white dots. I see, no, I've done a pretty good job. But there's one thing that I did that I shouldn't have done, which is that there was a consistent white dot that I removed consistently from every single frame that wasn't actually dirt at all. It was Harrison Ford's ear. Every time I come to it, it was like this little spec of something. And I thought that it was dirt so I painted it out. I didn't know until like the whole thing back that I actually removed. Now I'm so dumb and so green on the job that I'm afraid at this point. If they find out that I did this, I'm screwed. I'm fired. I'm out of here. So I let it go. I went to dailies the next morning, what we call the theater, right? The B screening room.  And they're looking at my shots in silence. Looks good. That shot. And I said nothing. And so in the movie Star Wars, ladies and gentlemen, there is a scene where Han Solo has no ear and learn something very important about him. Despite the fact that I feel like in some small way I ruined Star Wars. I also realized that while important attention to detail is a very important attribute of any craft that we do, the bigger lesson is what detail? Because if anybody is looking at Harrison Ford's ear, you're clearly looking at the wrong thing. Thank you. So I will say no more than to introduce the one and only your finale for tonight, Reds Graham! Guess what? We're not going to use the mic right now. I am the stage actor, so that's why I'm going to stand here and stage projects too. Also, I move around a lot, that's what I do. My name is Reds Graham, and since I got my introduction, I'll briefly introduce what I do. I know great through Patrick Rotten, through just impotent forming and general impotent form, but it's been a lot of my career doing games and working in games. So I'm working in video games since 2005, so for an hour or so I'm not going to be eating here or something. This is a story from a game you made for this called The Sims 4. Mostly they have a programmer on that game, and when I first arrived, the production cycle was not ideal. Here's briefly how games work. You have a designer or a set of designers, and they make things. So the designer will say, okay, I am going to make the relationship system. You have relationships. We want fathers, mothers, people who are in love, platonic love versus romantic love, all of these things. So that's what I want. Now I'm going to be pulling some engineers and some artists, sound people and production and everyone. So involve these people in, and then we make the thing. That's not how it works at EDA on The Sims 4. The way that it works is that the designer will come up here and say, okay, I'm going to make this thing. I'm going to work really hard on it, and I'm going to talk to some of my other designer friends, and okay, now who do you guys think it is? Okay, I'm going to read you back some stuff. This is all on paper. Okay, now I think it's ready. So the next step is to go to the Council of Design Gods and say, here is my design. I'm going to say, we shall schedule you for three days hence. And the design gods are eating grapes and drinking wine or whatever the designer sees, and they look at it and they may say yes or no, but it's a very gladiator thing. Proved or not, it was not approved. They go back and they redo it. And this happens a few times. This entire process can take them days, weeks. So then what happens? Well, then what happens is it's approved, and they celebrate. All the designers gather around, and they all sing songs and pull out hoots and things like that. They show them the barrel of a mortar, and they launch all the way over where we are. The gameplay is here. It lands here, and we're sitting there stroking our ears and solving problems that nobody had. We look down and we see, it's designing here. Yeah, this isn't even going to remotely work. Okay, so we go and we red line it up to stop and we say, no, this is going to work. We have our own work. We launch all the way over here.  And this happens over and over and over. It could take a month or something like this to go down. It's a mess. It was terrible, right? It's not a fun thing to go through. And it didn't create so much a wall between us. It created a rift between us. That's the much better word. We were not only, probably going to talk to you, but we were going to work in the same building, but we were actually discouraged from it. No, no, no, no. Let's go through the design review concept. That's what it's there for. Senior design leadership wants to pull on high and say, this is what needs to happen. So that should happen for quite a lot of people like that. They're all sorts of things. And then one of the problems that we asked for, for example, was engineers are like, how much money does this cost in the company?  And I laugh at it now. We kind of laugh and joke about it now. But it was, it was, it wasn't like we were miserable. We were frustrated. The engineers were frustrated. We were there going, wow, why is it like this? And that was just us. That was not because it's high in the sky. What do you do a little taste of what their experience was quite different? I'm going to do that with a visual. Is there something on the floor? Corey, you have a design. I guess you're going to come through. The designs are done. Someone is going to say, you are the next one on the list. So you're the next one who needs to have a design. Do you think as I go down the side, just tell me what's on the side. Right here? You're sure? I'm sure. Corey came up with, this is him. This is not anyone else. Corey, you must design a nine of hearts. That is your job, all right? You can design a nine of hearts. I can clean the dirt off. Can you do that?  I want to make it that close. It's a nine of hearts. It looks like a nine of hearts. It works like a nine of hearts. So we engineers look at this and we're like, this is never going to work. This isn't going to be a nine of hearts. It's all wrong. So what the designers heard from us, whether or not they're saying is you can't design. You design will never work. That's what they heard because of course that's what they heard. We sat there and we went back and we said, I don't know why the camera didn't go dark. They said, look, here's one reason it won't work. Here's another. Here's another reason. Here's another reason. These are all reasons why it won't work. So we take what is left of your shattered dreams and designs and put it away. We put it away in the box of shame. This is why I chose Cory because I thought it would be okay with that. So we put it into our box of shame here, just like this. You have a, what it wants is for you to take this pen. Mark, like you can sign it like the front part or the back part or anywhere. It doesn't matter. We leave the box of shame over there. So that's what they heard. And that's the problem. And that's a huge problem, right? The communication was the actual issue. We weren't actually saying that today. We were saying it won't work for these reasons because it's our game to set up. They've heard everything is bad and they've literally torn everything apart, but that's not the reality. Yeah. I'm not a plant.  I want you to make the truth of what's in that box, all the pieces of your torn and destroyed design that I want you to dump it out for everyone to see. All the pieces, okay? That's the reality. Hold it up for everyone to show. I'm just holding it. That's the reality. It's not perfect. It'll never be perfect. But it's close. But it's closer to me though. I mean it's closer to me though.  Would you take your receipt from that piece of paper? Because the thing is, it's not going to just put a card in there. But I didn't. I'm not touching anything anymore. Since I touched it, you were like, he's a magician. He's doing magic. Would you pass the card in front of everyone? If that corner perfectly matches. This is our show. So let's bring up to the stage all of our performers. Join us all as we play the long, uh, uh, plate, chess.  Well, that's all this is about. Give it up for Alyssa. Tonight, we do do this every month and I would love it for you to come back, bring friends, check out CoreyRosen.com to find out upcoming things who the cast are going to be. And also let me know what we should do in the future because we have more shows next year. Delight to see you all. Thank you for being here. Keep telling stories. Have a safe journey home and through the holidays. And thank you.


So, welcome to the 18th lecture of the NPTEL course on cryogenic engineering. We have done various topics till now and the broad topics we can classify them as first the introduction to cryogenic engineering. We studied the properties of different cryogens and therefore, properties of cryogenic fluids. Then we studied the properties of materials at cryogenic temperature and the last topic which we covered was gas liquefaction and refrigeration system. Having done all these four topics, now I will be changing some gears and we will be going to now gas separation which is a very important topic of cryogenic engineering. Having liquefied gas, having liquefied gases together and air being a mixture of various gases, whenever we liquefy air, we got lot of gases in liquefied form in air and now we have to separate oxygen, nitrogen and other gases may be argon from liquid air and therefore, we have to use a gas separation technique and this is the most important thing because gases are needed by every industry nowadays and therefore, this topic has got a very special relevance from users point of view from gas user point of view. So, topic is now gas separation. What we are going to study under these are different sub topics which are basics of gas separation, then ideal gas separation system just as we got a ideal system for every system to compare with, we got a ideal gas separation system also. Then we will study properties of mixture and the governing laws. Now, as you possibly know that we got several laws which govern the mixtures and they help us basically in understanding the partial pressure business and the total pressure and their relationship and they are very important to analyze these mixtures, so as to get the properties of mixtures at different temperatures and pressures. Then we will study principles of gas separation in broad and then separation process itself, the rectification and plate calculations. So, plate calculations actually essentially mean that there is a column which has got lot of plates and we have to calculate number of plates involved in that. So, this is a very important topic and which involves actually it covers a bit of chemical engineering also because it has got some mass transfer aspects associated with it. We will keep it of course for mechanical engineers however and therefore from this point of view I have basically going to cover this topic from mechanical engineering point of view. The current topic will be covered in around 7 to 10 lectures just as we had liquefaction in 7 to 10 lectures. Similarly, as we proceed ahead the number of lectures possibly will be around 7 to 10 and then tutorials and assignments are also included at the end of each lecture. So, in this topic what we going to learn is the outline of today's lecture will be the basics of gas separation in which we will study some gas separation methods and then we will find what is the ideal gas separation system and we will find what is the ideal work requirement for ideal gas separation system. These two sub topics will be considered will be taught in this lecture of first lecture of gas separation. As mentioned earlier the cryogenic industry is huge going to the various application of the cryogens both in liquid and gaseous states. For example, the use of inert gases like argon in chemical and welding industries has increased in the recent past. Basically I am highlighting the utility of these gases in various industries. Liquid nitrogen is used as pre coolant in most of the cryogenic systems also cryogens like liquid oxygen, liquid hydrogen are used in rocket propulsion. In the recent past liquid hydrogen is being considered as a fuel in an automobile. The production of ammonia in RCF industry for example, the fertilizer industry requires separation of purge gases like nitrogen argon and other inert gases. This production has to be done at cryogenic temperature and therefore, separation of gases play a very important role in fertilizer industry also. For most practical purposes it is considered as a mixture of 78 percent nitrogen, 21 percent oxygen and 1 percent argon. So, if you want to use nitrogen, oxygen and argon we have to basically separate them out from air. The other ingredients are helium, neon, krypton which occur in negligible quantities. So, normally as far as helium, neon, krypton are considered the you know take them out from air becomes rather difficult. So, normally air will be used to obtain nitrogen, oxygen and argon which are abundantly used in abundantly required in the industries. So, air serves as a raw material. Air is a raw material for the production of most of the gases and the process of separation of the gas mixture into its individual component is called gas separation. That is what normally we will define as. In other words, this topic of gas separation deals with separation of various gas mixtures and their purification. Now, how do we separate gas mixture? There are various techniques available. We just touch upon those techniques and then come down to the technique of cryogenic gas separation. So, what are these different techniques to separate various constituents of a gas mixture? One is using synthetic membrane. We will see each of these techniques in brief to support to understand how the separation occurs using synthetic membranes. The second technique is adsorption which is a physical phenomena as possibly most of you know. The absorption are the technique of separation of a gas mixture and then the cryogenic distillation. So, broadly there are four methodologies of which the first three are normally at room temperature while the third last one is cryogenic distillation or separation at cryogenic temperature or at low temperature. So, we will first study what these three techniques are and then we would go to cryogenic distillation in detail. So, let us see what synthetic membrane mean and how does synthetic membrane separate a gas mixture? Synthetic membranes are the porous media which allows only a certain gas molecules to pass through. So, very simple. So, you can see from this figure. This figure shows that the membrane in some cylinder and this membrane allows to separate a mixture of A and B molecules or a mixture of A and B components of gases under the piston which you see from the left side. Synthetic membranes are the porous media which allows only a certain gas molecules to pass through. The membrane in the figure allows only gas A to pass and hence separation occurs. So, in this particular figure what you say this membrane allows only A to pass through it while B cannot pass through it. So, what will happen? If I go on pushing this piston on the right side, the A will get A will pass through the membrane and on the right side of A as you can see right side of membrane what you can see is only the component A. That means, only the gas molecule with gas A gas will come through this membrane while the B gas would be always on the left side because B cannot pass through the synthetic membrane. For example, thin sheet of palladium allows only hydrogen gas to pass through. So, if I use palladium material as membrane material and then have a mixture of various gases in which one of the components is hydrogen and then if I use such kind of arrangement only hydrogen will be in this particular location where A is right now because this membrane will allow only hydrogen to pass through it while other gas members will not be able to pass through it alright. So, this is a way the membranes can be used. They are being used various membranes they got a preferential treatment preferential passage for particular gas and according to which they could be used. The second technique is adsorption. So, adsorption is a physical process in which only a certain kind of gas molecules are adhered to the adsorbing surface. Most of you know this adsorbent that you got a surface phenomena and if you got a A and B gases then only one of the gases can adhere to the mixture or it can get adsorbed on this adsorbent while other gas cannot. So, adsorbate in the figure adheres only gas A. So, this is adsorbate and it the gas only can get adsorbed on the surface of this adsorbate. So, it allows only A to adhere to the surface while B cannot adhere to the surface in a way therefore, a mixture of A and B will get separated. A will adhere to the gas adsorbate surface while B will be freely lying over here and then in a way this is separation of gases A and B. So, the adsorbate in the figure adheres only gas A to the surface hence the separation occurs. So, what you can see here the layer here will have only A components adhere to it while all the B components eventually will be all the A's would be getting adsorbed while B would remain there meaning which A and B have got separated. For example, finely divided nickel adsorbs hydrogen on its surface. So, if I want to separate hydrogen I can use nickel as adsorbate and hydrogen will get adsorbed on the surface of this nickel. Second one is absorption which we know that we got a sponge basically. So, we know that absorption is a chemical process in which substance in one physical state is taken into other substance at a different physical state. So, it is basically solid can take liquid or solid can take gas and one physical state is taken into other substance at a different physical state. For example, liquid being absorbed by a solid or gases being absorbed by liquid. So, what is the example? When an incoming stream of containing carbon dioxide is passed through a solution of sodium hydroxide the latter absorbs the gas and hence decreases the CO to contain in the outgoing stream. So, if I got a sodium hydroxide, sodium hydroxide will absorb CO2 the actually chemical reaction will happen between sodium hydroxide and carbon dioxide meaning which if an incoming stream has CO2 the quantity of CO2 can be lessened from this mixture and in a way separation occurs. So, if I got a sufficient quantity of sodium hydroxide all the CO2 from the incoming gases can be removed because sodium hydroxide will absorb CO2 there will be chemical reaction and may be some other compounds get formed during this chemical reaction. In a way this is a method of separation and therefore, this absorption is used abundantly in the chemical reaction. Hence, this chemical process helps in the separation of the mixture. So, in this case I am removing CO2 from the mixture by absorbing CO2 by sodium hydroxide. So, having done membrane adsorption and absorption having understood the basics of this now let us come to the distillation. Now, distillation is a process of separation based on differences in volatilities or the boiling points. So, I have got different gases and all these different gases have got their boiling points and they are different depending on the characteristics of these gases the boiling points will be decided and then the unique boiling point for each gas. Choosing these volatilities or the differences in the boiling point we have got a process that is called as distillation. So, here you can see that there is something called a schematically I have shown here something called a distillation column to which mixture of A and B gas A has got a different boiling point gas B has got a different boiling point and if this mixture enters this distillation column what you can see is the mixture A is at the bottom at the end and mixture B at the top. So, one which has got a high boiling point of around 90 Kelvin which is oxygen boiling point you will have it at the bottom and the liquid you will get for gas A at the bottom and one can convert this liquid to gas if one wants gas or one can get this liquid one wants liquid A also. Similarly, on the top what you get is a lower temperature here the Q is removed here the Q is added. So, you can see that Q in and Q out over here the low temperature boiling point gas for example, nitrogen which has got a boiling point of 77 Kelvin will be obtained at top of this distillation column this is just a schematic. So, a mixture of A and B enters the column and at the end this is now a cryogenic separation because the boiling points of these two gases A and B are different they can get separated A is coming at the bottom B is going at the top of this column. So, if the process of distillation occurs at cryogenic temperature this process is called as cryogenic distillation. The commercial production of gases like oxygen, nitrogen, argon, neon, krypton and xenon are obtained by cryogenic distillation of liquid air. So, liquid air actually is a source of all these gases and therefore, if you liquefy air that means all these gases are in the liquefied form in the mixture and this mixture can be fed to the column and according to the difference in the boiling points of these gases they can be separated and this is what we are going to see in the coming slides and coming lectures. The separation of a gas separation of a mixture can be done at both room temperature and at cryogenic temperature as we just saw. For example, in the case of air the following processes are possible. So, I just showed an example where the cryogenic distillation is done, but there is possibility that one can do this separation at room temperature also. So, if I got air at 300 Kelvin I can liquefy this air at 78 Kelvin which is the boiling point of air and from where I can get liquid oxygen and liquid nitrogen which have got boiling point of 90 Kelvin and 77 Kelvin and therefore, because this separation is occurring at lower temperature. First I am liquefying air and then I am separating the two gases from liquid air I call this process as cryogenic separation. The other process is now I have got air first at 300 Kelvin and first at room temperature itself at 300 Kelvin itself I am dividing or I am separating this mixture assuming that air is a mixture of nitrogen and oxygen only I got oxygen at 300 Kelvin and I got nitrogen at 300 Kelvin. That means, I am doing this separation of air at room temperature itself and then I get oxygen at 90 Kelvin and nitrogen at 77 Kelvin if I want liquid nitrogen and liquid oxygen. But you can see from here that the separation has occurred at room temperature for which I used special techniques called pressure swing adsorption, temperature swing adsorption and they are basically adsorption techniques of separating oxygen and nitrogen. These are more widely used these days it has got its plus points and negative points similarly cryogenic separation has got its plus point and negative points. Some of the advantages of cryogenic separation over room temperature separation are the separation at lower temperature is most economical. We will find later that as the separation temperature decreases the power input requirement or the work of separation requirement lessens. So, here we can understand that there is an increased difference in the boiling point of the ingredients. So, we can do that separation is effective because of the difference in volatilities. A large quantity of the gases can be separated in the cryogenic distillation and high purity of the gas can be obtained. If you do the separation at lower temperature we can get high purity of the gas we can obtain high purity of the gas at cryogenic temperature. These are the certain advantages of cryogenic separation. Let us understand is gas mixing is a reversible process what do I mean by that? That means if I mix the gas can I unmix it and can I mix them together. So, meaning which is this process a reversible process. So, consider a closed chamber filled with gas A and gas B as shown here and initially the gases are separated by impervious wall. That means A is here and B is here and there is the impervious wall which will not allow A and B to pass through. They are separate entities in this chamber if the wall is removed now the gases would mix. So, suppose I remove this wall you will find that A and B are together.  This is not possible and therefore, I will say that the replacement of the wall would not result in separation of gas and therefore, I can claim that this process is not reversible. It is clear that the mixing of two different gases is an irreversible process because unmixing or separation of the mixture requires work input. I have to do some work on this then only I can unmix the gas. The system in which all the processes are reversible is called ideal system as you know this. So, mixing and unmixing if it is possible if it is reversible process then I will call this ideal separation system. Although in reality such a system does not exist a system can be conceived as you know that every time normally we deal with ideal system of separation and therefore, we can conceive such a system wherein if I calculate work of separation or work of mixing and unmixing I have to first conceive an ideal system. I am going to conceive a system constitute to serve the required purpose as explained in the next slide. So, I am basically having a ideal system of gas separation now and how does this work ideal gas separation system. So, consider a closed chamber filled with a mixture of gas A and gas B as shown over here and there are two pistons one is red and one is black and again I got a mixture of gas A and gas B. This two pistons as sure by arrows can be moved inside and can be taken outside also.  The chamber has two frictionless opposing pistons made from semi permeable membrane as shown in the figure. So, these are not only pistons they are also membranes and they are semi permeable membrane meaning which they allow only one type of gas A or B to pass through it as we have seen earlier. So, we got a piston which will compress this gas at the same time it will separate one of the components of this mixture. As seen earlier a semi permeable membrane is a film which allows only one kind of gas to pass through, but not the other alright. So, we will this membrane will allow only one type of gas to pass through it. The left piston which is a red it will allow only gas A to pass through it and it will not allow the gas B to pass through it alright. So, basically when I start pressing this left piston to the right it will let A go through it, but it will not allow B to go through it. Similarly, when I press B on the left side it will allow only B to pass through it and it will not allow A to pass through it. Similarly, the right piston allows only gas B to pass through, but not gas A. This is what we call as a semi permeable membrane working like a piston in this close chamber. So, as if I go on pressing this two membranes or pistons you can find the separation has started occurring. So, I am getting on the left side of the membrane only A and I am getting right side of this green piston or green membrane only the component B. So, when I basically reach both the pistons reach together A and B would get separated. When the both the pistons are moved inward the mixture is separated and it would look like this understood. So, I got a mixture A I got a gas A and gas B separated from mixture of gases A and B as seen here. Since the processes are reversible we are claiming this particular process to be reversible what should happen the system interacts with the surroundings to maintain a constant temperature. So, all these processes are happening at temperature being constant T m. So, what I am doing basically I am pushing this piston B and piston A inwards. So, I have to do some work W A and W B respectively and at the same time because the compression process occurring some q r is being released some heat generated is being released. So, that the temperature T m is maintained I am saying that the temperature T m is all through constant and because of this q r temperature T m is being maintained because of this interaction with the surrounding the constant temperature is maintained. The work of separation is the work required to compress the compress each gas from its partial pressure P 1 A to P m and P 1 B to P m. The piston A is compressing the gas B while the piston B is compressing the gas A alright. So, W B is the work done on the piston B while W A is the work done on piston A and what is this compressing? Compressing gas B from partial pressure P 1 B to the mixture pressure P m and the whole process is carried out at temperature T m. So, here you can see that the gases A and B are being separated have been separated here. Since the left piston is permeable to gas A the gas A exerts no pressure on the left piston alright. When this piston moves the pressure is exerted on this piston by gas B and not by gas A. Similarly, the gas B exerts no pressure on the right piston it will be gas A which will exert pressure gas B will just pass through this gas A just passes through this. When both the pistons are moved inward the mixture is separated at constant temperature T m because we are calling this the temperature remaining constant in this case alright. So, this is a separated gases A and B the pressure here is P m and temperature being T m the pressure being P m and temperature being T m the entire processes are assumed to be reversible. So, now I find that the mixture has been separated, but because this process is reversible now this process should also reach back to the earlier point where it started from. The process is reversed due to the difference in the concentration of gas A and gas B. So, slowly gas A will start diffusing through piston A and gas B will start diffusing through the piston B because they are semi permeable membrane and slowly the concentration balance will get created slowly there will be difference in concentration on the left side of the piston and right of the piston for gas A as well piston A as well as for piston B and slowly the process of diffusion will start and slowly this piston would start moving back. It will take lot of time, but because the process is being reversible the process would start and therefore, meaning which the gas A will start getting combined with gas B that means the mixing process will start a reversible process of mixing will get start. First we have unmixed or separated A and B, but now slowly gas A will start coming in gas B start coming in and process of mixing will get started. Hence the mixing of the gases would move the pistons away and produce work. So, here with time the gas A will start coming in the gap between piston A and B and it will start pushing this piston A back and piston B back that means the work will now get produced by the system. Earlier we had put in the work we had work done on the system W A plus W B. Now the same work will get created by on piston A and piston B by the gas because now the gas is going to work on the piston. So, here what you can see is piston A is moved back piston B is moved back and slowly a mixture of A and B getting formed in this space. So, this is basically the reversible process which is what you are seeing here occurring now. The work produced in this mixing process is same as the work done to separate at constant temperature T m. The final condition is system with a mixture of gas A and B at P m and T m. So, ultimately I get a mixture of gas A and B at P m and T m. So, what you see here now in which again now because the work is kind of expansion of the gases I am supplying Q R the temperature being kept constant the surrounding is now putting some heat inside. So, that the T m is kept constant temperature is maintained and W A and W B is the work done by the system work which is produced by the system during mixing. Also the partial pressure of gas A and gas B will be P 1 A to P 1 B. So, ultimately in this mixture it will have partial pressure of P 1 A and P 1 B as it was previously. So, ultimately I will get now a mixture of gases first I had unmixed the mixture and again mixture occurred automatically and if I put in the work W A and W B again the process would repeat. So, this is what we call as a reversible process. We are consuming a system and wherein we can call this particular process as a reversible process of gas separation. So, this is my initial condition when I got a mixture A and mixture B gas A and gas B in a mixture form. This is my final condition where I got mixture separated in gas A and gas B. The moment I say they are reversible process I should have the arrows like this also. So, I can go from initial to final and final to initial in both the cases temperature T m is maintained constant. So, basically the gas A is getting compressed from P 1 A to P m when I am pushing this piston and gas B is getting compressed from P 1 B or the partial pressure of B to P m. In other words thermodynamically each gas is compressed reversibly and isothermally from its partial pressure to the mixture pressure. So, what is what I am doing basically while separating this mixture I am compressing reversibly and isothermally gas A and gas B from its respective partial pressure to the mixture pressure. This is what basically I am doing in separating this gas mixture. In order to understand the processes of compression say gas A from P 1 A to P m the following analysis is done. Now, basically I would like to calculate the work of separation of gas A and gas B. When I say work of compression is nothing but work of separation and this will give me ideal work of separation. This is what I am going to calculate now. So, now let us see the ideal separation system. Let us do the calculations to understand what is the work of separation if one goes for a ideal separation system. Let the molecular weight of gas A and gas B be denoted as mole A and mole B respectively. The number of moles of gas A will be given by this is very simple mixture family which I am going to just kind of revise and go ahead. So, if I want to calculate number of moles it will depend on how much grams of gas A is there divided by its molecular weight that will give me moles. So, N A is a mole of moles of gas A in a mixture of A and B. So, N A will be given as M A upon molecular weight of A. Similarly, N B will give the moles of B that is M B upon molecular weight of B. The total number of moles in the mixture N M suppose the mixture number of moles in a mixture are N M you know N M is equal to N A plus N B.  The mole fraction of gas A is called Y A which is N A upon N M and Y B is N B upon N M. So, Y B and Y A are basically the mole fractions of gas B and gas A respectively. Now, this is what our initial condition was of A and B when they were a mixture at T M and temperature of T M and P M pressure and the partial pressure were P 1 A and P 1 B. The corresponding volume occupied by the mixture was V total and I can apply now simple gas laws which is P 1 A into V total. This is for gas law ideal gas law for gas A and similarly I will have ideal gas law for gas B. So, what is the pressure of gas A P 1 A into V total is equal to N A R T where R in this format is what is we call as a universal gas constant similarly I will write the same equation for gas B also. If I combine them together P 1 A plus P 1 B into V total is equal to N A plus N M N B R T M. So, P V is equal to N R T is basically I am applying for gas A and gas B and also a mixture of gas A plus gas V. Note that the volumes are always the same because A and B together are occupying the same volume and individually also are occupying the same volume meaning which P 1 A plus P 1 B is equal to P M that is what we have been talking about. And now is a final when I got a separation has occurred and I got now particular volume of V A associated with gas A and particular volume of V B associated with gas B while the temperature is same as T M. And now the pressure of the gas A here is P M the pressure of the gas B here in V B volume is P M. So, again I apply the gas law the ideal gas law for gas A and gas B now the pressure of gas A in this volume of V A is equal to P M. So, P V is equal to N R T for gas A which is P M into V A is equal to N R T same thing I do for gas B. And if I now see that if I divide this by this what I get is V A upon V B. This will basically give the ratio of how much volume is occupied by V A and V B. It will basically give a function depending on what is the ratio of molecules of N A moles of N A divided by moles of N B. So, how many moles of N A are there how many moles of B will decide what is my V A and V B are. The volume occupied by each of the gas is directly proportional to the number of moles that is what we have just seen. From the earlier lectures the work requirement for unit mass of gas compressed isothermally is given by W I by M dot which is T M into S 1 minus S 2 minus H 1 minus S 2. This is what we had done we had derived this equation in the gas liquefaction cycle. So, basically W I is a ideal work done of compression basically because as we earlier said as earlier pointed out that separation is nothing but compressing the gas from partial pressure to the mixture pressure P 1 A to P M or P 1 B to P M. So, W I by M is equal to T M into S 1 minus S 2 which is entropy difference minus H 1 minus H 2 enthalpy difference. The net ideal work requirement of the separation process is the sum of the ideal work requirement for gas A and gas B. So, I can write mathematically that W I is equal to W I A plus W I B. The total work of separation is equal to work of separation of gas A plus work of separation of gas B. And dividing by M dot I get this W I by M M M divided by W I A M M plus W I B divided by M M. M M is nothing but the mass of the mixture. So, this is what we have just seen the total mass of the mixture M M and is the sum of gas A and gas B. We can write M M is equal to nothing but M A plus M B absolutely clear till now rearing in the terms. Now, I am just writing this terms in a different format as given here. So, W I by M M is equal to W I A upon M A this is nothing but work of separation for gas A multiplied by M A by M M plus work separation of gas B divided by M B W I B upon M B into M B by M M. So, I am just writing M M as W I M A M A by M M M A gets cancelled what I guess W I by M M which is what you see here. So, what I am basically you know writing this expression as W I by M M is equal to work of separation of M A into this component plus work of separation of B into this component. Here M A and M B are the masses of the gas A and gas B respectively. So, this is what we have just seen. Now, I can write an expression for W I by M A also. The work requirement for each of the individual gas is given by following equation. So, W I upon M A is equal to T M into S 1 A minus S 2 A minus H 1 A minus H 2 A. This is the expression we have just seen of work of separation when I compress the gas from 1 A to 2 A position for gas A. And similarly, I can write the same expression for gas B also. Substituting and rearing in the term if I put this value over in this equation I will get a very long equation. So, substituting this by this and substituting W I B upon M B by this what I get is this very big expression over here. T M is the temperature of mixture which is remaining constant. Now, let us find some expression for this entropy difference and enthalpy difference. So, this is my expression. What you can see from here that the T M which is a mixture temperature figuring out here and this is a work of separation of the gas. And as you can see that if the T M is lowered or the mixture temperature is lowered W I by M will be the work of separation will be very less. That shows directly that the temperature is very low or in the cryogenic temperature region the work of separation will be very very less. It is clear that work requirement decreases with the decreasing temperature. Hence, the separation of mixture at the cryogenic temperature is most economical and one point is proved mathematically from here that if T M is less if a mixture temperature is less the work of separation will be very very less. The subscripts 1 and 2 denotes the initial and final condition respectively. What does it mean? What is the condition 1? It means that for each gas S 1 and H 1 are at the partial pressure before separation because each gas is being compressed from its partial pressure to mixture pressure. So, one condition the S 1 and H 1 are basically conditions prevailing at partial pressure before separation while S 2 and H 2 are at the mixture pressure because the gases are being compressed from their partial pressures to the mixture pressure after the separation of the mixture. For the sake of understanding let us first evaluate the entropy and enthalpy terms for this. So, let us see if you could substitute by some simple expression for this enthalpy and entropy differences for gas A and gas B respectively. For an ideal gas the specific entropy S and specific enthalpy H are expressed as below. So, S is equal to C p log T minus R log p plus some reference entropy term. Similarly, enthalpy is equal to C p into T plus this reference enthalpy term basically is a any temperature any pressure one can select and what we mean to say that it should remain constant throughout calculations where S R and H R are some reference values they could be at 77 Kelvin or boiling point or 1 bar and 0 Kelvin or whatever because there are various temperature entropy diagram which can have different references values and what we mean to say that whenever we refer to such different diagrams we should keep the same reference values. Hence, S and H for each gas A are given as if I put now this general expression for gas A I will get this expression well similarly I will get for S 2 A that is after at a temperature T m and mixture P m I will get this expression alright. Similarly, enthalpy values at 1 A and 2 A conditions are given by this expression. The entropy and enthalpy terms are given what I want to basically find out is a difference in S 1 A and S 2 A minus H 1 A and S 2 A and if I put those values over here I get this expression this is for entropy difference and this is for enthalpy difference and if you see now because the temperatures remaining same from 1 A to 2 A this terms can get cancelled. So, this term will get cancelled similarly the reference values are same they will get cancelled over here and in this case again the temperatures remaining constant these terms will get cancelled.   Similarly, I can do the same thing for gas B and I will get expression S 1 B minus S 2 B minus H 1 B minus H 2 B is equal to R B log P m upon P 1 B. So, I have done a major calculations and whatever expressions we have first got to calculate the work of separation wherein this entropy difference and enthalpy difference figure this complete term now will get replaced by this for gas A and gas B complete term will get replaced by this.  So, this is what we got an expression now this is what we got for gas B. So, I can put this expression back in my W i by M m is equal to this and my expression will be now replace this term by this in this expression and replace this enthalpy entropy difference by this and my final expression therefore, will be like this. So, I get W i upon M m is equal to T m into M a upon M m like this this entire term get replaced by Ra into log P m by A plus M b upon M m comes over here and this entire term of enthalpy entropy difference get replaced by R B log P m by P m.  Since the process occurs at constant volume V m using ideal gas equation which is P v is equal to N R T I can write this expression which we have done earlier P m into V m is equal to N m R T m. So, I can write the same expression for gas A and gas B.  So, P m upon P 1 A is equal to N m upon N a is equal to 1 by Y a we know that N a upon M M m basically moles of a divide by moles of mixture is equal to mole fractions of gas A.  Similarly, I can do for ratio of mixture and gas B also and I get the same thing that P m upon P 1 B is nothing, but N m upon N B is equal to 1 upon Y b this is what we get from here now. So, I have got a ratio of P 1 by P 1 A figuring in the earlier expression I can replace that by 1 by Y a where Y a and Y b are the mole fractions of gas A and gas B respectively. The ideal gas equation can also be expressed in terms of mass of the gas as shown below. So, I can write this expression P v is equal to N R T for gas mixture gas A and gas B I can write this N m or the molar fraction as the mass of gas mass of mixture divided by molecular weight of mixture this is basically definition of N m I am just replacing this N m by mass of M m upon molecular weight of M. So, P m V m is equal to M m upon molecular weight of M R T M and same thing I am doing it now for gas A and same thing I am doing for gas B here M a upon molecular weight of A here M b upon molecular weight of B will figure. So, why I am doing all these things basically I know now that P m V m is equal to M m R T now here R by molecular weight of M is nothing but now specific gas constant. Here universal gas constant R divided by molecular weight of A is specific gas constant of A and here also similarly the universal gas constant divided by molecular weight of B become specific gas constant R B as shown over here. So, basically R upon molecular weight of M or universal gas constant R upon molecular weight of M will come as this R which is specific gas constant similarly I will do for gas A similarly I will do for gas B why in general R A is equal to universal gas constant R upon molecular weight of A where universal gas constant is 8.314 joules per mole Kelvin. So, basically now I would like to express the express have the earlier expression in terms of mass of gas A and mass of gas B also alright. So, universal gas constant R and specific gas constant R are the universal gas constant and specific gas constant respectively. From the earlier slide choosing the ideal gas equation in terms of gas mass what we get is this. So, I am now writing P by M V M is equal to M M R M T M this is what we just saw P V is equal to M R T P 1 B M is equal to M B R B into T M dividing one over the other I will get P M V M upon P 1 A V M now I cannot cancel both R and T because T M and T M will get cancelled over here V M and V M will get cancelled over here what I get is P M upon P 1 A is equal to M M R M upon M A R A which is nothing but 1 by Y A because P M upon P 1 A is 1 by Y A we have just now earlier seen that what does it mean same thing I am doing it for gas B P M upon P 1 B nothing but 1 upon Y B. So, what I get from here is equal to 1 upon Y B ultimately I will get M M R M upon M M M A R A upon M M is equal to R A into Y A if I just rearrange this I want an expression basically for this which is what is figuring in my expression for work similarly for gas B.  So, if I put those expressions I will get this equation. So, W I upon M M is equal to R M T M Y A log 1 by Y A plus Y B log 1 by Y B the expression looks very simple now I have got a RT mixture temperature and R M Y A upon 1 upon log 1 upon Y A plus Y B log plus 1 upon into 1 by Y B where P V is equal to if I just replace by R M T M and M M here and want to convert it to the molar form I can write work of separation per mole of gas mixture W I by N M and here immediately universal gas constant will figure please understand this please understand the relationship between the universal gas constant and specific gas constant because this is a work of separation per gram of mixture per mass basically and this is a molar expression. So, you got a mass expression and a molar expression also as soon as the molar expression comes here universal gas constant comes as soon as the mass comes over here specific gas constant comes over here. So, the ideal work of separation per mole of mixture gas A gas B will be given as the molar expression ideal work of separation per mole of mixture that is W I by N M is equal to RT M Y A log 1 by Y A plus Y B log 1 by Y B this is for a mixture of gas A plus gas B I can extend this to A B C or A B C D we can have different components in a mixture and similarly I can show an expression for A B and C mixtures on the similar line if the mixture is composed of three different gases gas A gas B and gas C the ideal work of separation per mole of mixture is given by W I by N M RT M Y A log 1 by Y A plus Y B log 1 by Y B plus Y C log 1 by C C if you have got a D we will get Y D log 1 by Y D what are Y A Y B and Y C some molar fraction of gas A gas B and gas C in the mixture what is T M temperature of mixture universal gas constant. So, this is basically work of separation of per mole of the mixture work of separation per mole of mixture what I am doing is basically find out work of separation is nothing but work done to compressed each of this component gas A and gas B and gas C from their respective partial pressure to the mixture pressure as we have seen in earlier reversible gas separation process and this is what ideal work of gas separation will be the actual work of separation. However, as you know will be different and therefore, we introduce a term in the next slide called figure of merit which we have already introduced in a gas liquefaction also. So, generalizing the above equation for a mixture of N constituents we just showed for A and B we also showed for A B and C, but if the mixture which has possibly has got N constituents what will the formula be now? The formula will be W i upon N M that is work of separation per mole of gas mixture is equal to R T M into sigma j is equal to 1 to N sigma Y j log 1 upon Y j. So, if I got j is equal to 1 to 2 N equal to 2 I get Y 1 log 1 by Y 1 plus Y 2 log 1 by Y 2 if 1 and 2 are respective gases I can have N gases and therefore, I can have log 1 upon Y 1 plus Y 2 plus Y 3 plus Y 3 same terms will repeat and the summation of all this thing will give the work of separation per mole of gas mixture where Y j is the mole fraction of the j th component. So, basically this sigma expression comes normally we will have 2 component or 3 component or maximum 4 components not more than that. So, from the same thing this is the ideal work of separation I define one more term as I said earlier similar to the liquefaction system the figure of merit or FOM is also defined as figure of merit is equal to ideal work divided by actual work. The ideal work could be in molar basis or on a mass basis also say W i by N M divided by W i by N M you know the negative sign is basically the work done on the system that is why. Similarly, W i by N M which is on a mass basis now divided by actual work of separation actual work of separation must be much higher than the ideal work of separation and therefore, the figure of merit will always be less than 1. So, this is what we have learnt we have basically got an expression for work of separation we understood what a figure of merit would be of a given system. So, just to summarize what we did in the first lecture of this topic of gas separation I just take you through a some summary points. We just discussed different techniques employed for gas separation which are synthetic membranes adsorption, absorption and distillation. The separation can be done at both room temperature and cryogenic temperature when I use room temperature technique I use normally the method of adsorption or I can use membranes or I can use absorption while the distillation normally done at cryogenic temperature. In an ideal system all the processes are reversible and the work requirement in an ideal gas separation is called ideal work. So, we just got an expression for ideal gas separation a work done in order to or a work requirement for ideal work requirement for gas separation and what is that expression the ideal work requirement per mole of gas mixture to separate a mixture with n constituents is given by this general formula. So, general formula tells you W i by N m is equal to R T m sigma y j into log of 1 by y j when j is given from 1 to n constituents n equal to 2 then and therefore, a and b are the two gases then y a log 1 upon y a plus y b into log 1 upon y b where y j is the mole fraction of the j th component. We got a small self assessment exercise to given please go through that thing and kindly assess yourself for this. Based on whatever we have learnt in this lecture I am devoting more time in the lecture 2 for solving tutorials. So, that you understand the relevance of the formula which we have just derived in order to calculate the ideal work of separation and this is a small self assessment test please go through it and assess yourself there are answers given at the end. Thank you very much.