Hello everyone, I'm Michael Abadi and welcome to State of the State 2016. This is episode 7 and I'm honored and thrilled to welcome Bill Lee to the studio and the Montpelier and the show and Bill Lee is running for governor under the Liberty Union party ticket and he was he's I gotta say iconic baseball player with the Red Sox and the Expo's career went from 69 to 82 and 73 all-star helped win that AL pennant in 75 and since then has been playing ball right through he's been baseball goodwill ambassador to Cuba you mentioned China Moscow China 75 Moscow and 88 Soviet Union and you played you played in Venezuela as well played in Venezuela for two years and also you gained some union experience as an MLB player you were player rap yes I'm responsible for more millionaires than anybody in the state of Vermont by taking the money from the billionaires and dividing it up amongst all the players because they're all making a million now right and we can we can talk about labor more but you've got that experience and then it's about 25 years you've been in Craftsbury as farming yes I've been the worst farmer in the history of Craftsbury all my turkeys got eaten baby turkeys by a fisher cat while I was on a road trip and my ex-wife was there and I had a trap out there and it got caught one of its paws got caught and it gnawed off two of its talons to escape and she didn't get a shot at it so I was out of the turkey business and then the sheep they got ill and had ducks and porcupines and everything were all I mean at the porcupines most of the raccoons got after the ducks and then my last chicken I remember seeing it dying a pile of feathers and it lost in the third round and it was a barb rock meanest hand that David Reed my farmer he loved that he'd come up on his tractor and that that barb rock and attack him and you know you don't need a handgun in the northeast kingdom you just need a couple of barb rocks and two gray geese uh-huh and they'll protect your whole house now how did how did you um how'd you find that spot I had come down that road after writing the book in 84 the wrong stuff I wrote it up in abacorn madsenville on the Quebec side in a little chalet and then I'd come to get pizza and I'd come in to uh got all the way to Newport and then came up 14 one time and I saw this guy hanging with a scythe it was Robert Anderson he had the biggest farm in Crassbury and the next farm was the Reed farm and went by it saw Crassbury fell in love with it and about two years later the fantasy camp came to me John Savage from the Chittenden Bank here in Stuart Savage Adele Savage they came to New Brunswick asked me if I would come back come back to Vermont and help him with the fantasy camp and they said we'll put you up in in the Demick's house in East Hardwick when uh when he went to Florida and I had all these Red Sox relationships here and uh Ken Squires his father had a cabin up a Middlesex notch stayed there in the fall and that was the fall when we had the 16 inch snowfall on the 12th of October you know which said welcome to Vermont and I learned that Middlesex notch is pretty high up yeah and I learned that and then I came back and then Scott Reed's barn collapsed and he had to sell his cows he was dairyman of the whole Lord northeast kingdom the best lowest lucasite level and he comes there and he introduces himself to me and says I've my father's selling parcels would you like to come live with us and I went up there and I shook hands and he sold me his 14 acres on the top and that was where I've been living ever since and David's still alive he fought on Iwo Jima he's one of the last surviving Marines of Iwo Jima now you did service yourself I read somewhere you six years yeah last Red Sox that was drafted I think there's some stuff I was the last Red Sox that was almost drafted I was I was smart I passed my AFI's physical in Oakland and immediately got on a plane told the Red Sox and they flew me on the Red Eye and I enlisted in the Army Reserve at the Boston Army Base and that kept me precluded me from having to go to Vietnam but they army got mad yeah they were gonna send me to NAMM anyway and then I basically I pitched well enough that if you throw well you know I was worth more with the Red Sox than I was walking point up and you know up on the DMZ but I was lucky a lot of my Red Sox players did go to NAMM Bill Campbell and stuff and and I was cursed by having to process all the dead bodies from New England so I worked the MTS computer that was your gig that was my punishment and wasn't it was it was tough work wow you know and I have to say you can come get whatever's left to your son and an Oakley cluster and a bronze star and I was that'll give you a sense of the consequences of war like nothing else exactly and I became I was a long haired hippie I got busted back to PFC before I even got out because but you know I was in the head I straightened out all the all the papers and publications in my Aguas Puerto Rico when I was stationed at the the base in my Aguas Puerto Rico which is a U.S. protectorate so I did that and then I was chemical rail radiation biological warfare officer for the 1173rd and you know that I had to do atropine injections and nerve gas and it was tough it was I did six years but all the time I got the pitch too which allowed me to pick their time right and they would schedule my weekends around times when I was I'm actually responsible for annual training I changed it from summer camp which the army used to do and we called it annual training because I made my my living in the summer so I did all my military work in the winter okay and so you could shift I could shift it around and I you know the squeaky wheel gets the grease and I was pretty smart and the army agreed with me and and then it affects change yeah and I just I'd go to the rifle range I bring all the brass and ammo back and you know I was I was pretty proficient in the military I was soldier of the cycle at Fort Polk, Louisiana in fact I was the the number one to come out of there and the only one not to go to Vietnam and in fact they gave me a test and I passed it and they wanted me to go to Fort Wachuka become a second Louis and immediately I would have been in the NSA so I could have been Snowden too huh national security national security of talk give back to you know life and growth and farming and your your your time as a farmer is giving you any insights and how this the stake and help out farmers yes I believe in Alan Chadwick in the Indonesian hexagonal double digging technique for planting and allowing your soil to be better organic you have less runoff you have more soil more soil conservation and I believe Pete's greens is using a lot of that not so much row planting that they do nowadays you know I think they were ahead of their time as far as providing food at a smaller like Vermont has not a lot large pastures and stuff but we are a lot like Vietnam we're a lot like the Highlands we're wet we're damp and but we have the seasons and we can grow everything we want bok choy melons we can grow it's this is the perfect place Vermont and I've always been an organic farmer and you know I don't spray my apples I take them the way they come and I press the juice we have presses up there and one day a month Bill Pierce allows people to use his press and we're all kind of in this group together and it's that's what I love about the northeast kingdom and I think all of Vermont should adapt the kingdom philosophy nice now you see the state I don't know providing incentives to farmers to move more in in that direction I do know that there have been farmers terracing for rice you mentioned Vietnam and we're actually as we get warmer and wetter it seems to be the it's going to be the norm yeah you know I I have a southern exposure on the other 42 acres uh that by wine partner I make wine in California I make a petite saura saura cabernet a cote de rome blend and if you take Vermont and go right through it goes right same place in southern France so eventually but they have the way the the currents are and stuff I do not believe I think we'll always have these extreme temperature swings here sure you know and you're gonna get that polar blast because that tongue and the way the shape of the rocky mountains are it comes that's called an Alberta clipper and it flows through but I believe if you have a southern exposure protect your grapes and and and plant them properly and shelter them a little bit you know and maybe you can shelter them with solar panels behind there so you're collecting the southern light and have your wine terraced you know we could have a viable grape culture right sure yeah and you got a lot more of a talking about season extension too and really getting I believe there's going to be a season extension our falls have all gone longer our winters are less harsh uh you know and uh we do not get that uh 15 days in 88 that we got where it's 40 below I haven't seen that since I've been right right that could have been the last gasp of real winter as the polar ice caps melt I mean hell there's tourist ships going all the way around point Barrow all the way through yeah they're becoming shipping the northwest territories and stuff so it's it's a shipping line I propose that the Canadian government that they do away with the the lock system and the great lake system and and go right out of Churchill Falls and run all your produce and everything there run it through Hudson Bay and it's a shorter distance to Europe huh I thought that would be economically viable and then for energy for us I've always proposed to the the premiers I've known all of them in New Brunswick for the last 25 30 years that why don't we harness the the Bay of Fundy title bore with the 45 foot tides in the spring and the fall I mean there is so much energy to be made that way with the transmission line instead of running all this freaking lignite and this heavy fuel oil that blew up in Lake McGon thick that was a terrible tragedy and that was so close to us in Craftsbury you know when that blew up and that was going to the Irving factory over there in St John I'm pretty sure it was maybe a couple years ago you won't believe how many transport trucks from New Hampshire and everything cross Vermont and go into the port of Montreal and get their fuel oil and everything at a lower price because of the dollar up there and then transport it back across the state line in Vermont we're just through and look at all the logging trucks Quebec logging trucks on 91 and 89 and on 12 and 14 and everything that are taking our premium beautiful logs and taking them to the shampoo and milling them up there you know we've got to get more sustainable we could add we could add the value here is what you're saying and that's exactly add the value here do it on a smaller operation do it you know with these beautiful new wood misers these beautiful little saws you know and a lot of people are doing that and do more customized sawing within the area for for our needs right re-adapt so that that's a model where it's not drawing in that one big industry that's going to provide us you know 800 jobs and another that dog don't it's it's sort of a small entrepreneurial economy that's what we're going to be we're going to be that the Vermont brand is golden when you put Vermont on something you can slap a 10 percent more on it just because it's they say it's from Vermont they know it's good they know it's clean means and we've got to do that and maintain that you know that that market by cleaning up our waterways cleaning up our streams getting rid of the big cow farms you know going down using more of their land on their farms for more organic farming and be more diversified that that seems to be the trick of it how do you help them convert we're going to have to help them convert we're going to find a way because it's all about market if they can make more money with us cows senator yeah we got to show them that 2000 cow farm ain't cutting it you're dumping your milk anyway because wisconsin's setting the price of milk you know these guys over there in wisconsin with these cheese heads on playing for the packers you know those guys are telling us what the price scales up yeah they're scaled up in a way we can yeah they're scaled up because they're big they got subsidies those giant farms in Iowa and stuff you know they don't stay in Iowa in the winter so we're looking at really it's I mean we're kind of we're getting there we're out maybe are we a sort of a specialty ag market that serves so we live near massive population centers too we can get our goods to a lot of people if this was the united states right we're that little word right there right that's it we're number 49 yeah 630 000 people in education we're good and and the quality of life we're good everything we're good we're not alabama louisiana or mississippi right so um you're leading me to ask as we are a small state we are population did near double when the interstates were put in and i'm wondering are you someone who sees that we really ought to work on increasing the population here are we going to see climate refugees from the coast i mean are you i see them coming are you seeing a uh i don't know we're like who how many decades out but um i thought they'd be here a long time ago and nothing happened nothing happened but i see the change right now and i see it because finally people are realizing that when the army corps of engineers put six inches on the jetties all around florida georgia and the carolinas they did it 20 years ago they knew something was happening so i think the finally with that flooded louisiana the temperature down there my daughter says is unbearable right now as far as think how warm it is up here and do that on steroids people south of us and never get a break from it they never get a break i think there's going to be more people moving north i think that's the future yeah but it's with air conditioning there was this huge southern migration but yeah that that that was because they go down in the winter i mean you're people up in north throy and stuff and your big farmers they've got their places down in fort meyers they're all redsox fans i know i know all of them down there and they they all get down and the they go down and they sit down there and complain that there's nothing to do i know one farmer it was up here and his wife begged him to go to florida he did not want to go to florida he said okay we retire he goes to florida he was dead within a year don't go to florida it's a trap especially if you're a hard-working farmer and stuff because there is really nothing to do down there so retire here retire lovely quality of life cross snowshoe yeah get a beagle yeah go out and follow some you know hairs around and at least keep your cardiovascular up stay in shape david reads 92 and he's still kicking so most of you old cramudgin farmers don't go to florida it's a trap unless you're playing ball and i still play you go and then you're getting your exercise and we won the vermont state championship uh middle wine burger my catcher that was your last visit to montpellier right last closed last visit i threw 12 innings i got a one out double in the 12th and he drove me in winning run ended the senior year senior league season right is that right here right here at your rec field down there at robin roberts field where he was uh 18 and six in the a league back in the old days and one of the great pitchers that i knew in my life so complete game 12 innings 140 pitch victory congrats yeah bill mac poor guy struck out 22 of us but when he woke up in the morning the times argus had a big l right next complete game lost 12 innings yeah um we're talking retirement how about um pre-retirement people have a working life you've got some experiences as a as a as a union wrap the state's made some movement at a minimum wage talk about sick leave what would you like to see move forward you got a number on minimum wage where would you see that like 15 just like you know and uh you don't be diversified you know uh if you if you need extra work go out because i'm going to raise the price on the bud light cans for the return they're going to go up from 5 to 10 cents because you can make more money picking up bud light cans in the spring after the skidu trails go down i can tell you a place in the northeast kingdom where you can make 200 dollars in an afternoon they are the ones you always see they're the ones you always see that in mcdonald's mcdonald's is going to get tax more uh white flour uh cigarettes alcohol i think i think germany sources trash and charges would charge the equivalent of the mcdonald's for like okay 20 percent of the trash on the roadside is mcdonald's we're gonna and it's not really a tax it's like yeah you know take care of what you put out into the world that's that quarter german of me it's in our dna we think that way you know you know the germans i said one uh a long time ago everybody should drive a Mercedes or a bmw because they're the most engineered cars in the world and my father says you come home with a chap car or a german car i'll shoot you he fought on okinawa and and tinien yeah you know and he had the the silver star with the oak leaf clusters and uh he was tough you know and that's our relatives i'm the first i'm the baby boomer born in 46 right i'm the responsible we were the worst generation they were the best generation we were the worst generation we were worse because they fed us on time they put us on the potty on time and we were all regular and we all i was bubbly fat and uh i'm just the same as i was when i was 18 months old so you you had sort of a classic 50s upbringing and boy didn't i i was leave it the beaver found it found your way i was walley i was los angeles mom smoked cigarettes had the meal on the table yeah you know i am the classic hollywood kid yeah north hollywood well the boomer's got the boomer's got plenty to be proud of i do believe that i don't i don't every time i look in the mirror i see what a squander i am of of you know i i was bought into this thing this world war one was unnecessary that was a bunch of in-laws fighting amongst themselves for the control of some donut shop in berlin it'd be nine be liner and if world war one was not right then hitler wouldn't ever came about so we wouldn't have this world war two if we don't have world war two we don't have the cold war we don't have the cold war we don't have korea we don't have vietnam what would the planet be like if we were a peaceful race yeah and all those resources were spent to exactly a growth rate maybe we would all be like canadians you know well the nicest people on the earth married last two wives are Canadian they're um you actually got to experience their healthcare system i did as an expo but i didn't take advantage of it i paid you know but i would get an x-ray of my arm and i go in and i didn't have their insurance benefits but i would go in actually i didn't pay the expo's paid but after i retired i still go back i get all all my implants so i'm not in past tense actually present tense present tense i get all my implants at half price i get my shoulder surgery i got the big zipper here for my rotator cuff larry coglin for five thousand dollars it would have been 50 75 thousand so what are what are they doing and i got morphine drip every six minutes it was what are they doing right what could we learn from the canadians what could we actually they actually tax their people properly and they get it back and they have all these sin taxes on food and everything and all that goes to their medical and stuff and uh people are healthy people are happy people go out at night and they actually walk around the streets downtown until two thirty three o'clock in the morning and they socialize and then they go home and wake up at 12 o'clock and they don't want uh they don't watch sunday night football because the cfl is on thursday and friday they reserve their weekends they reserve their weekends for themselves and their families and they're not they're not all committed to uh nfl well it seems like with trying to roll out singer paying vermont at what's that point you actually led with the unpopular thing to say they tax their people properly and that seems to be where shumlin walked it back he did nothing was politically viable to sell a payroll tax at well i don't know where it was seven nine percent and you got to pay for it how do you pitch it how do you pitch it you got you just got to get through you get what you pay for if you want security and you want to wake up and you want to like your job and you want to go to the job and know that if you fall down or something you're going to be taken care of that's a good way to live your life go north to canada they're happy they're happy go to switzerland they're happy go to norway they're happy go to sweden they're happy their workforce is happy our workforce isn't happy you know because of a bunch of republicans with a bunch of short arms and long deep pockets they look like tyrannosaurus is rex is and they go they go like this all day we're not going to do it we're not going to pay for it you got to pay for it or eventually there's going to be a revolution and you're seeing with bernie sanders you're seeing it with the black lives matter and eventually these people are going to get upset and they're going to take back their country and the u2 percent are going to have to go to norway or north of norway because that money's it doesn't trickle down reagan was wrong you know thomas malthus was wrong john kenneth galbraith was wrong all of its bait well kenneth galbraith was a canadian he was actually all right he's the only economist i ever really read that i enjoyed and his son's not that bad except he got into the oil patch and that's why sue minters running against him um thank you that was a lot um so in terms of uh this this state now um you mentioned a lot i guess what you just said i think a segment of the population found the sort of kind of wake up call some people heard that as scary and some people heard that as hopeful you know what i mean i know if you're educated it's hopeful if you're uneducated it's scary you know because it's like oh my god they're going to take away and they're going to all of a sudden these muslims and everybody going to come into my trailer park and shoot us up that ain't going to happen in vermont trust me it ain't going to happen you invite people of other face of other religions that's the key to life is get to know different people and embrace that there'll be no radicalism in this state this state you know it's uh it's a great estate and it'll be fine yeah i'm not worried about there's a bedrock stability here huh i think so i think we came here everybody here and the reason they came here was to get away from the madness and uh if we can't survive here where the hell are we going to go from here now um you speaking on canadian health care and learning from canada um they also have a multi-party system and um you are you are creating a multi-party governor's race just by throwing your hat a literal hat into the ring and i just i did you were you paying attention to how that multi-party system works up there oh yes it's i was part of the renaissance i guess what's the benefit of of that you get more voice are we lacking you get more voices you get more uh discourse you don't get this this controlled by the super media fox cnn and everything else they just stored it it's wrong read amy goodwin read the books that are out there that have the truth rumsfeld in 1983 was saddam hussein's buddy buddy they nerve gas the curds they gave him money like that and he goes no that wasn't me and then all of a sudden they showed him a picture of him shaking hands he goes where did you get that picture oh yeah that does look a lot like me yeah rumsfeld liar republican liar it's a it's amazing how the iraq war continues into 2016 to be a central campaign issue i mean that is just it's it's this it's fear multi-decade it is i knew it the day it happened the day i was with uh kin burns i went to kin burns house in uh wall pole and saw the second uh the second tower collapse with kin burns in wall pole and i said this will go on forever this is exactly how the crusades started and how we got our ass kicked by salad in a long long time ago and you just cannot defeat monotheistic behavior like that you've got to be polytheistic we vermoners we worship trees we worship river we worship quail we worship pheasants kind of have an ackee right there we're having an ackee yeah that's nice and you have to have that mentality everything is alive but when you practice in an abraham and everything else everything is dead you know and what do you want you want things alive you want things dead you know and i'm not going back you're sitting with father crow hail and brimstone and me saying you're going to hell because hell is uh mississippi one is 99 degrees and 90 percent you're uh you're yeah you're speaking nicely on um i guess how spirituality informs informs your politics it did um and that night i'm very spiritual i'm very zen buddhist i'm very flexible i do my yoga every day i have full range of motion i concentrate on being able to pitch every sunday and going 12 innings and i'm going to do that till the day i die excellent maybe the governor's race will get in its way but i'm pretty sure you guys are all set you know especially half the people in vermont have already voted because they're leaving for florida election day itself doesn't matter so much anymore it's funny how october is kind of harvest season in baseball where things get serious farming and politics so here we are i imagine you'll be are you're going to do much traveling around the state i know you're not soliciting campaign funds not playing that game are you going to do a i have to be consistent with my values and my values are you shouldn't have to pay for a government you shouldn't have to pay people to uh to get them out there and stuff it's uh one man one vote you know we only have three votes in uh you know for presidency anyway right very very low electoral we're very low so yeah they used to say as main goes so goes the nation and then they said as main goes so goes vermont's right that's right that's because fdr wasn't it um thanks for uh expanding the playing field and uh putting your hand in the ring and getting getting all these uh i want i want the conservative vote because i am more conservative you know than any republican out there and i am a gun toter i go out when i carry a gun i see no grouse when i carry a baseball bat birds fly all around me so i carry a baseball bat because i don't really want to shoot them and eat them anymore we do have time i thank you so much for getting here and enjoy campaign season yeah this is uh this is as good as it gets here right here this is uh you know i've already won in montpellier i would like to win again because i think i'll do the best job for you because uh i'm the only guy that'll have his hands in his own pockets you are yeah you're on a winning streak aren't you yeah all right take care now thanks for getting there thank you very much


Hi, everyone. On this session, I'm going to talk about depth team metrics that matter. We're going to learn what are they, why they are important, and how we can use them, and how we can optimize our process after monitoring them. My name is Avishag, but all my friends call me Vichy because it's easier to pronounce and it's shorter to write. I started my tech career on 2013. I was working as a BI developer for the military of Israel. A couple of years later, I moved to all scripts. I started working there as a BI developer as well, but quickly I moved to the R&D team as a software engineer. I worked for all scripts for almost four years, and after that I joined Cisco. In Cisco, I was working a software engineer as well in the cloud security department. I developed features for Cisco umbrella specifically for the SWG solutions. In the middle of 2021, I started working for Linerbi. I worked there as a software engineer as well as team leader. In Linerbi, we are developing delivery intelligence platform and other solutions to help R&D groups and teams to optimize their processes. Other than that, as you can hear, my main language is Hebrew, and I did my studies in the Ben-Gurion University of the Negev. This is in south Israel. Now, I live in Tel Aviv, and on my free time, I enjoy dancing and hanging out with my friends. But enough about me, and let's dive in right to the session. A few days ago, I met friends from the university. When you meet friends that are working as developers as well, there's always this question of how things at work, how is your job, and the answer is binary most of the time. It's either you are very, very happy or you are very, very sad. What I like to call the happy developer and the sad developer. The happy developer is coding most of the time, especially new features. He manages to deliver fast and in high quality. He also feels the impact on his company's customers, and he basically has the time of his life at work. On the other hand, we have the sad developer. The sad developer is very, very sad, and not because of the company's benefits. He struggles. He's working very slow, with lots of context switch, and most of the time is not even coding. He handles many conflicts and rarely develop new features, and he is very, very not satisfied with this current position and current situation. Now I want to talk a little bit about Dora metrics and how they are related to this specific situation. Dora metrics develops research and assessment metrics, a group of four metrics that was defined by Google after years and years of research. This group of metrics measures your team's performance and help you to understand whether you perform well or not, and how healthy your development pipeline is really. Dora metrics can be divided into two categories. The first category is speed, and the other category is quality. I want you to start thinking about it as roads construction and vehicles that use the road that you are building. Your dev pipeline is represented by the roads while the code changes are represented by the vehicles. When you think about the roads, you have many kinds of roads. Some of the roads can be made by different materials. You also have highways, carriageways, cityways. You have many kinds of ways. So when it comes to your speed in the road, you have many factors that can affect on your speed. The obvious one is the road itself. You can drive faster on a highway rather than a cityway, but not all the vehicles share the same speed. Motorcycles can be a lot faster than tracks, for example, which lead me to the second factor, the type of vehicle. Roads quality can be measured in the long run as well as in the short run. If the road was built in a high quality, you will meet that in the field. You will probably have less cracks on the road itself and less accidents, and driving there will be a lot smoother and safer. You can also measure your quality when you meet an accident. If you are able to recover and fix it quick, it indicates that the road is stable and safe for the future and also has the right qualities for fast recovery. Let's see now what are the specific metrics you want to start to measure and how we can do it. Cycle time, our first metric. How quickly your code moves from coding state to deployed state? Think about moving your car from point A to point B. If you'll be able to do it fast, it indicates that your speed is high. Some applies to the coding delivery. If you are able to move your code from coding state to production, you are actually delivering in high speed, regardless the type of vehicles you are using. But our roads are not always straight, and sometimes we need to have stops in the way. Each team might calculate their cycle time in a different way. For example, in our R&D group, we calculate our cycle time as a sum of four stages. You start with coding time from the first commit you do when you are walking on a new branch till the moment you open a pull request that is actually ready for a review. Then you move your code changes into what we call pick-up stage. The moment you open a PR till someone in the team is start reviewing it. After that comes the review stage. From the very first comment that PR gets till it's good to go is being approved and gets merged. This is the review stage. Finally, we have the deploy time. We have the deploy stage. From the moment you merge your pull request till the code changes are actually in production. In our R&D group, we are calculating it by tax creation. These whole stages together are representing the whole cycle time, and the summary of the times together gives us the cycle time itself. When the cycle time is low, you are performing well, but when the cycle time is not low, you are performing not that well. Another way to measure speed is deployment frequency. How often your work is deployed to production and customers actually use it.  We are given a limited time of one hour to drive this road. The more laps you finish, the faster you are. This applies to deployment time as well. The more deploys you manage to do, the faster you deliver. Both cycle time and deployment time together are indicators of your team's speed. Moving to quality. CFR, change failure rate. How often your deploys results an issue or a bug. This is our long run test for our road construction. This is something we meet only after deployments, sometimes only after customers meet the feature. Reducing CFR will indicate that you are delivering in high quality and also that your pipeline is strong and stable for deliveries. The next metric that measures quality is MTTR. Mean time to restore. When and if you have an issue in production, you want to measure how quickly you recover from it. As for the road and the cars, when you have an accident, you want to measure how quickly you can recover the road itself and handle the involved cars. Doing it fast implies that your road has the right qualities for recovery and also that you as constructors, you have the right skills to fix it quick. Some applies to the coding world. Fixing an issue quick can be achieved when your code base is good and has high quality. Also, these fast fixes can be achieved when you have a stable pipeline to deliver the fixes very fast. Being able to do it quick and immediately indicates that you perform in high quality. Starting measuring this group of four metrics will help you to get a sense of how your team is performing. You will also know whether if your developers are overloaded or not. And this will help you to also understand what changes you need to do in order to create a better workspace and pipeline for your team. Another metric worth mentioning is PR size, pull request size. Till now, we discussed mostly about the road. Now we'll give more focus on the car that uses the road, the type of vehicles that use the road you just created for them. The vehicles are actually the code changes you want to deliver to production. The driver is a developer. Sometimes you have more than one developer that is responsible for the ride. And the number of code changes the PR size is like the car size. So you have many kinds of sizes and types of cars. You have mini cars and you have vans. You have motorcycles and trucks. You have bicycles and buses and endless variety of vehicles. The size can affect both quality and speed. Think about who can be faster in traffic, motorcycle or a truck. Think about when you have an accident, for example, which one will be a lot smaller, which accident will be smaller, the one of the motorcycle or the truck. PR size has a major impact on your speed and quality, especially when you want to deliver fast. In linear B, we did some research regarding to PR size based on our customer's data, and we discovered many interesting things. We wanted to see the relation between pull request size and its life cycle duration. We discovered that PRs under 200 changes will get merged much faster, even twice as fast. And why is that? It's because small PRs are just more attractive. You will pick them up faster. You will be able to review them much faster. You will also review them much better because they are easier to review. And that will also impact your quality. With that, you'll be able to merge them a lot quicker and deliver the code a lot faster to production. Another interesting thing we discovered is that working and delivering small pull requests will also increase your deployment frequency, meaning that if you'll be able to split your work into smaller pieces, into small chunks, naturally, you'll deploy more releases. And in general, teams that are maintaining small pull request delivering approach has very low cycle time, which means they are performing in high speed. They are reaching to production faster and more frequently. Therefore, their developers has more impact on their customers all the time, which maintain their happiness as well. Now, how can you know what is your performance? You will have to start measuring these metrics. If you'll be able to measure them, you will also know whether you perform well or not. And you also know many more insights as well. Is your team suffers from bottlenecks? Is your team overloaded with tasks maybe? Are you planning your tasks properly and give the right estimated time for each task? These are crucial things for you to know because you want to maintain happy development pipeline in order to maintain happy developers and happy teams. In Linear B, we use our own product for measuring all these metrics, but you can always measure these using external plugins and APIs of your product tools that you are using, and you can always use spreadsheet and other tools instead. Now, let's say you already started measuring these metrics, and now you want to know what can you do in order to improve the process itself. Now, let's talk about the common delivery process. The typical development process, most of the dev teams and organizations share. You start by coding. You do your coding. You do your things there. You do some tests and unit tests. You have some checks in dev environments and your local environments, code formatting, and so on and so on. And after that, you are done. You open a pull request and wait for your review. This process might take a little while. You get comments. You resolve the comments. You fix some things and so on and so on. When you are done with the review process, you are able to merge your PR. Now, we are getting into the integration part, where you integrate your changes with the rest of the system. Sometimes you have integration phase before the merging, and sometimes you have it after the merging. And sometimes you even have the integration tests and process in both before the merging and after the merging. When you are done with this integration phase, you move to the deployment phase.  I know that there are many practices of the process and not all companies work the exact same way, but let's consider it as the most common delivery process. Let's get back to our metrics. Cycle time metric meets us along the whole process from the very first commit to the code is actually in production. There are many companies that have even more stages in their processes. For example, QA stage or beta stage, and there are far more many other stages there. So make sure you do these adjustments while you are measuring your cycle time. Other metrics are taking into consideration in other parts of the process, but how can we really speed up the whole process? One of our main goals is adding the group and development team is also to provide our teams and ourselves with the best development experience. We can achieve that by CINCD automated processes. CIN stands for continuous integration and CD stands for continuous deployment. CINCD approach made a revolution in the dev world years ago. For some of us, CINCD were a given concept for our very first job, but seniors developer in the crowd here can tell us they were not there always. CINCD created the integration and the deployment process into automated processes. If in the past we had to copy manually as the files from one server to another, now we are able to do it automatically. These processes not only increased our speed dramatically, but the lack of human mistakes and misconfiguration also improved the quality as well and makes it a lot safer to do these processes. If you haven't engaged any kind of tool for your CINCD, you should. There are many available tools for it in the market. For example, drone, Jenkins, CircleCI, GitHub actions and more. The thing is that they are not covering the whole process, the whole delivering process. There is still a gap, a gap that developers are suffering from in the beginning of the delivery process. If we'll zoom in into that part, the beginning of the process, we'll see the combination of that phase. Data shows that most of the time there, the most of the part of it, is actually counts as idle time. The time where the code changes are just waiting for a review, or the review already started, but it gets into a long loop of virtual discussion with you and your team members. This wasted time is happening mostly because of context switching, and it costs a lot of time as well as destruction. Even if you're working with small PRs, you might suffer from it. The developer suffers from idle time, and it's not always dependent on them. If we could add some automation layer for that part, the beginning of the process there, we could increase and speed up the whole process. The idea here is to understand that not all code changes you want to merge are the same. Not all pull requests act the same. You have PRs with only readme file changes. You have PRs that are considered as security label of the project changes. You have PRs of only images changes. Every PR has its own personality and can act differently when it comes to merging it. The continuous merge approach talks about categorize your PRs and give a route for every PR. Now, when you have this pull request categorization, you'll be able to add relevant automation, for example, auto merge or auto approve or even auto assign for a review and more and more. This automated layer will cover the beginning of the process and will increase the speed of your team. This is what we call CM, continuous merge, and with CIMCD will have the whole process covered. Continuous merge, it refers to the pull request life cycle of the software release delivery process and you can engage it in two ways. The first way is to get your PR more attractive in an automated way. You can send personal casting notification to the reviewers and you can also add more context into it. For example, estimated review time. The second way is to automatically categorize your PRs and add actions of automation after that. In our R&D group, we are doing dogfooding, so we are using our own product for that. We are able to get notifications as soon as the developer assigns us as reviewers. We also get more context. We get the estimated time this review might take us. In addition, if the PR is small enough, we can even approve it right away from Slack. So we don't have to do this context switch between multi-platforms. This whole thing helps us to reduce the middle part of the process. The review time is being reduced dramatically. And with that, we are managed to speed up the whole process of delivering. And in scale, if you are working with a group of developers, a big group of developers, it can save a lot of time there. In the market, there are many other tools for that as well and many plugins that you can use and engage to your pipeline. As for PR automation, we are using GitStream Platform for automated PR categorization. We are defining our reprovals in SCM file, and with that, we are able to define and automate actions that we want to perform on different kinds of PR. And all of these together along CINCD tools allow us to have a stable and healthy and happy pipeline, and provides us to focus more on coding and less on other things. Remember, when your development pipeline is happy, your developers are just happier. If you have any questions, feel free to send a direct message to me. I'm Evel Bel, also on LinkedIn. Thank you for listening to this session and have an awesome summit and a nice day. Bye, everyone.


Our family tries to bring a little bit of Japan into Columbia, South Carolina. We've opened Inakaya, which is a sushi bar. We opened Menkoi, which is a ramen place in both downtown and in Sandhills. And now we're bringing a Japanese bento convenience store to Columbia, South Carolina. Right now we're specializing in Japanese products and also the owner of Inakaya is a fantastic chef and he's been cooking all his life and he makes these bentos every day fresh for everybody. We're very excited to open a place like this in Five Points. I know Columbia has been doing really hard to clean up Five Points area to make it very accommodating for our business owners and we're just lucky to be here. This is wonderful. Here we got a new location opened up. We got Japanese culture being immersed into our community, which look we're open. We're open for business, innovation, ideas, relationships. And this is just another one. It's a heart. There's so many neat items in this store and opportunities for people. And I think being next to the university is just a plus. I think people more and more want to explore different cultures and the food. And Inakaya has produced some of the best sushi for so long in our community. Chef Sato is a well-known figure here. So everything he does brings a little more culture to us and we love it. I think for us, I mean what we want from Five Points and like we want in every neighborhood, we want diversity. We want more people to be immersed. And this is not just a village for the university. It's a village for the whole community. And this is just one step getting us back to kind of that base where we're an 18 hour a day place where people can come get services. They can get food. They can have entertainment. It's a one-stop shop for everybody.


So guys, you know, we just find that weapon and you think that's so unique I've got to try and make a build out of it and that's what I've done I found a bubble blaster, the envoy, the longhorn, and I thought I've got to make a build out of that And that's what I've been using today. As it going guys, my name's DPJ If you enjoyed the video, leave a like, really helps out and if you like what you see more, be sure to subscribe Okay, so just let me play out there. I ain't known for builds. I mean, it ain't something I really post But I just had to showcase this one. I originally built it for myself But because it's so powerful, maybe even considered overpowered I thought you know what? I'm going to respect soon anyway and build something else now I'm kind of liking it. I may as well share this with someone out there That's fan this weapon and for you know what? I'm going to try and build something like that So if this video can help you out or assist you in any way in giving you advice and how you can make this thing even Powerful, that's my job done. Simple as that. So the weapon is the envoy's longhorn Mizer plus 10 This raise, it is a Scales with strength, dexterity and faith, faith being the holy damage Which is what the bubbles cause simple as that guys So I respect and went into faith. I put 85 into faith, but the other 10 is from my talismans I also put strength dexterity for when enemies are coming at me and I'm slapping them You know, I'm making people and I'm slapping them. You know what? Because it's a great hammer This class is a great hammer.  It's way more efficient than you think. I haven't got to the stage yet and I've been using this for two or three days murdering bosses And I haven't come to the stage where I thought, you know, I might have to switch that weapon out for something Because it's just not working that that's probably coming it probably will come But right now it hasn't that's what I love about this thing. It just works It works against groups of ads. It works against single target damage If you can lay all these bubbles or most of these bubbles on one target, it shreds people So, yes, now what I will say is because I don't want a video going on for I hate watching guides where they're going for like seven hours I've basically covered most of these items in previous guides So what I'll do is there's an item here you don't have or you're interested in for something else Uh, if you've got a guide, you'll find it linked in the video description.  I'm pretty sure of it. So, yes This but this build is based on me mainly trying to make up my bubbles as powerful as possible and it's kind of worked So what we're doing here is we are using the Uchiketana, which is a puke. I'm stabbing myself with it paired with this Bloodlust and Facinity increases the tap power Makes this and the bubbles more powerful That scales with my seal and the incantations. I'll show you in a second It also scales with this which is my Biotiful Helmet, which if you look at raises the potency of bubble based skills amazing We also have like I said, these uh, Rage of Stats As you can see here we gain mind intelligence Uh arcane, but it's mainly guys for me about the faith give you that gives you five faith This one here gives you another five faith So there we go. Simple as that Two-finger heirloom. We have the Mirko Sosio We have the Lord of Bloods Exultation and we have this one here the Shard of Alexander, which I'm not long got Doing the Alexander quest, which is pretty fun. So yes, this greatly boosts your tap power of skills Works wonders. We also guys get extra damage from this here my physics Holy Shredding Crack tier temporary boosts holy attacks and that works wonders. I also have the strength Not crystal tier temporary boosts strength, but you can change that out for some of the chaos. I mean there's quite a few I've just Strength fees that are a part of the build because of the weapon scales with it, but I mean it ain't a must I'd say the the Holy Shredding Crack tier is but here guys It's probably something you can probably work with or you've probably got something I ain't got that Will probably help this even more and yeah, like I said, I ain't a build Kind of person. So if you have any advice for me to make this even better, I'd appreciate it so the actual armor I just do it just I just got them on I got random shit on to be honest. I'm not even gonna lie to us So If you can if you can carry if your equip loads good enough and you can have tank on why not? Simple as that you want to go light go light simple as that Where what you want if you want simple as that people. Okay, so let me show you how things work So as you can see if we go down to my status, you can see the The right armament there number three is eight hundred and sixty four If I pop My golden vowel with my seal Boo You'll see Nine hundred ninety four. Nice.  That's to puke Go back to it 1,193 nice if I drink my physique, you'll see that raises even more Boom 1,320 simple as that guys Simple as that guys it makes things just brutal It really does it makes things just utterly brutal now the incantation i'm using with my seal uh are Just the golden vowel increases attack power and defense for self-analyze and we also have a tree here which to be honest I mean if you're stabbing yourself more after the night, you're probably going to have to heal And you can use your flasks obviously But if you got them at fp points, I mean Man, so I use them and this this this heals me an absolute turn now. Let me show you It could be due to my faith. It could be but you know, I'll be here all day But it was easily if I hold it long enough. It'll basically fill my health bar That's what I love about it And that's basically what I do guys. That's basically what I do. So if I'm going into a bus fight What I do is I will Put my golden vow Simple as that I will stab myself in my stomach Simple as that I will drink my physique. I will stab myself once guys. My controller is dodgy. I don't know why it does that Then I drink my drink Then I'll switch my thingy walking to the fire blow horns Now the blood loss from the supuku It don't last very long. I'm not sure exactly how long it lasts I know the physique lasts about three minutes and the golden vow lasts quite a while too Easily throughout a bus fight was a good chance that supuku may wear off I haven't tested how long it lasts to be honest, but it's still decent enough for me to shred Absolutely every bus I've come across quite easily to be honest quite easily. So yeah, like I said I'm using the uchi katana I'm using my envoys lung horn both in my right arm Left arm use my seal How many is the envoy crown? Other armor can be anything you want We're using talismans with a lot of blood excitation, blood loss and vicinity increase the attack power. This works amazingly with this We need a katana and supuku We have the mocha saucer which raises stats. This is mainly for raising faith get more damage Two-finger heirloom again raises faith get more damage Shadow of alexander Just greatly boost attack power skills Marvelous, then we're using the The physique which is the whole shredding crack tier again Boosts holy attacks makes the bubbles absolutely ridiculous shreds enemies as you saw at the start of the video I'll play a couple more clips for you so you can watch this more slowly in action Is a great build like I said, I will be respecting soon. So hopefully this can help somebody out Um, and there you have it guys now in regards to uh incantations Should have said this earlier you can put anything you can put whatever you want here You can add more to this if you want there's plenty incantations you can use I mean if you like your seal your faith is high there's plenty that can do extra damage for you plenty guys You haven't got to I mean you can take this build and evolve it make it better That's completely up to you Well, there we have it people there we have it and you know what I hope the video helps you out If it does leaving a like really helps me out if you're new around here I want to see more outing videos be sure to subscribe Again, thanks for stopping by and hopefully people. I'll see you on that next one


afternoon anyway good that at least a few have turned up otherwise I would have to reschedule the entire class anyway. So, as a one more small correction to the previous class that we that I just want to bring forward I think one is one person who observed it and he was correct the mean temperature for the high speed flows I had told that it should be 0.5 T wall minus T infinity plus C into I think it should just reverse the sign it should be T adiabatic wall minus T wall where C equal to 0.22 so I think I had given this as C into T wall minus T adiabatic someone has correctly pointed out that since the adiabatic wall temperature is greater than the wall temperature. So, this has to be positive so that the mean temperature now is increasing rather than it should not decrease because now with the use of adiabatic profiles for example, if you had plotted Y versus T which we had done this is your T infinity from here the profile should start something like this and so this is your T wall. If you had applied isothermal boundary condition without discuss dissipation it would have come something like this therefore you see the average temperature has to now go up earlier the average temperature was between T wall and T infinity now the actual temperature will be like this something like it will go up inside. So therefore the average temperature has to account for this increase therefore this has to be positive here if this was T wall minus so generally your adiabatic wall temperature will be greater than your wall temperature okay. So, this will be positive and therefore this will increase your T mean temperature otherwise it will decrease the T mean temperature which is not physically correct okay. So, this please incorporate this particular correction and now we will start a new topic it is the same solution to external boundary layer flows but we will use what is called as an approximate method of solution okay. So far we have been doing exact solution so called exact solution where we had derived the similarity equations for the different configurations and we had solved it but we cannot solve it exactly we have to solve it using some numerical method but nevertheless the solution is the solution is for an equation which is actually an exact equation okay. Now we will look at techniques where we will approximate the solution by means of some profiles rather than trying to solve by a numerical technique that the way that we were doing till now so we do not know the profiles how they look so but we got that as a solution of the similarity equation. Now we will approximate the profiles as something depending on the order of accuracy you know you can use a linear profile or quadratic or cubic or fourth order whatever polynomial so we will substitute that into the governing equation once you know the profiles we can determine the expression for boundary layer thickness the thermal boundary layer thickness and therefore the heat flux nusselt number and so on. So this kind of technique is also called the integral method many people also refer this as the approximate okay. So the starting point of this is to start with essentially an integral form of why this is called an integral method is you operate with integral form of the governing equation form of boundary layer momentum and okay so why do we use the integral form is of course integral form is more helpful when you are approximating some solution putting it inside and integrating it out directly okay. So therefore this is more convenient for the approximate solution to work with an integral form and I am not going to now derive the integral form because if I remember correctly I had already derived a particular version of the integral form if you may recollect your earlier notes for the flat plate Blasius solution we try to find the expression for boundary layer thickness delta so as something like square root of ux by uinfinity right. So this was derived by integrating the momentum equation from 0 to delta and from there we had solved an ODE to get the expression for delta okay so in fact at the time I told that I am not going to derive it again because we will be using that as a starting point. So the point where we left off so we integrated the x momentum equations I am just going to write it just to show you how it looked du by dy dy is equal to nu du by dy between the limits equal to 0 and equal to delta okay. So we just integrate the boundary layer momentum equation for a flat plate okay we could also include your pressure gradient term so that will be additionally plus uinfinity du infinity by dx and integrated between 0 to y dy it is nothing but delta okay so how we got this because originally this term was nothing but minus 1 by rho dp by dx and we saw in the boundary layer that the pressure gradient along y is negligible therefore we can apply this equation to the inviscid potential flow outside and we can directly find that this is equal to uinfinity du infinity by dx okay and when you integrate it across the boundary layer so that will be this will be constant okay for a particular y location so you can directly say that is multiplied by delta okay. So if you have a pressure gradient that term also enters into this final expression and after we broke this term we integrated by parts and then we use the continuity equation to make some approximations and finally we arrived at this particular form 0 to delta u du by dx especially the left hand side minus uinfinity 0 to delta du by dx dy this is equal to nu du dy 0 to delta plus uinfinity du infinity by dx okay so I think we arrived at this particular form for the entire left hand side term after we use the continuity and we integrated it out and from here we are going to start now okay so this is nothing but the momentum integral equation but still not the final form okay so I am just going to rearrange some of the terms in fact what I am going to do here is I can once again integrate by parts okay so I can do this as d of uinfinity u by dx minus u into du infinity by dx I can I can just re-express re-express that way and I am going to multiply throughout by a negative sign and if I just rewrite this a little bit so this will be d by dx 0 to infinity 0 to delta u infinity minus u into u dy so u infinity into u is basically this term minus this can be neatly written as directly 0 to delta d into uu by dx dy right so du square is nothing but 2u du dx okay so I can just write this as d by dx so I can take d by dx out so 0 to delta so I am multiplying throughout by negative sign okay so I can write this as so this is already negative negative of negative is become positive so u infinity into u minus uu okay so that is this particular term okay plus the other term which I which I have written this is du infinity by dx which I can take common from here as well as from the right hand side term okay so this can be written as du infinity by dx integral 0 to delta okay so here I have a negative sign here and I multiply it with a negative sign so this should become positive okay so this should be a positive again I multiply with a negative so that should become negative and this one is already negative goes to the left hand side term that becomes positive so this becomes u infinity minus u dy okay on the right hand side now if I integrate this from 0 to delta so at this at y equal to delta du by dy should vanish okay so this becomes minus u du by dy with a minus sign so this becomes positive this becomes new du by dy at y equal to 0 okay so I have probably skipped a couple of steps but I think you can understand straight away how that comes out you want me to explain again or is it okay so till here you know how it has come out okay from the previous derivation so from here I am just rewriting this first time as d du u by dx and this I am integrating by parts again okay so I can write this as u infinity u d by dx minus u du infinity by dx so therefore so this term and this term can be combined I can take d by dx out of the integral so 0 to delta u infinity minus u u okay so this is u infinity into u this is u u so I take small u common u infinity minus u dy and the other two terms so here du infinity by dx is common to this and this okay so and I can I can write this as instead of writing this as delta I can write this as 0 to delta dy okay so that is u infinity that is basically this u infinity into dy minus there is again this u dy okay so which is what I am writing here together on the right hand side term this is 0 to delta so at delta du by dy is 0 right so therefore this is minus du by dy at y equal to 0 already I am multiplying throughout by minus so this becomes du by dy at y equal to 0 okay so this is my final expression in fact I can also rewrite in a more familiar form so I can write this as d by dx of I can take multiply and divide by u infinity square for this particular term so this will be u infinity square into I will just denote this as something like delta 2 plus in this case I can multiply by multiply and divide by u infinity okay so I will call that as some delta 1 into du infinity by dx on the right hand side I have this so where my delta 1 will be so multiply and divide by u infinity so this will be u infinity 0 to delta so this is u infinity by u infinity which is 1 1 minus u by u infinity into okay so I am not going to write exactly like this I am just rewriting slightly in different manner just a minute so I am multiplying and dividing it so that delta 1 into u infinity is here and delta 1 is defined in this particular fact okay and delta 2 so I am multiplying and dividing by u infinity square and divide by u infinity square this will be 0 to delta 1 minus u by u infinity into u by u infinity dy okay so this is also another nice form that you find in many of the textbooks nevertheless all the three whether it is this form or this form this form they are all the momentum integral equations or integral momentum equations okay I personally prefer looking at this form this is almost the final form and this gives you a lot of information because here this delta 1 which I have defined here there is a particular name to it this is also called the displacement thickness and delta 2 here is called the momentum thickness okay so and this is your okay I hope you have a good understanding of what is displacement thickness and momentum thickness okay from your incompressible flows I am not going to go into an explanation for that now it is only so this are not really measurable okay this is what you have to understand unlike the boundary layer thickness which you can measure that as a location these are conceptual values which give you a sense if you suppose replace the boundary layer with a potential flow profile so how much the wall has to be pushed up okay so are displaced in order to satisfy continuity or satisfy conservation of momentum okay so that is this location so these are all not measurable okay these are something if you are conceptualizing and usually these are much smaller than your actual boundary layer thickness okay so this is your momentum integral equation so you are writing this in terms of the momentum integral your displacement integral and so on for the case of flat plate without the pressure gradient the second term will be 0 so you do not have anything in terms of the displacement thickness so for flat plate your du infinity by dx is equal to 0 and this will lead to the form you can write u infinity square d by dx 0 to ? okay so this is the integral momentum equation for flat plate let me call this is number one okay this is the one form that we will be using to substitute all our approximate profile now same way we will derive the integral form of boundary layer energy equation okay we start from the conventional energy boundary layer equation and then we integrate it out across the boundary layer thickness and we arrived at a similar integral energy equation okay so we start with our standard energy equation we do not assume any viscous dissipation term here for flat plate case without viscous dissipation this is your equation at y equal to 0 it could be either wall temperature fixed or your prescribed heat flux which is constant and at y going to infinity t is equal to t infinity at x equal to 0 also the same thing follows so what we are simply doing is integrating again now when we are integrating now we cannot integrate it till the boundary layer thickness because now we have to integrate it till the characteristic thickness for the energy which is the thermal boundary layer thickness okay so we integrate it till ? t of course you know we are not making any assumption whether ? t is greater than ? or less than ? whatever extent it may be we are just integrating till the edge of the thermal boundary layer and so we will try to eliminate v so that we write everything in terms of u so we will see that the second term can be integrated by parts so this can be written as 0 to ? t okay I can write this as d by dy of vt integrate between 0 and ? t that is nothing but v into t between the limit 0 and ? t okay minus integral 0 to ? t into t dv by dy okay on the other side you have a ? t by ? y between the limit 0 and ? t and a ? t dt by dy is 0 okay it has to satisfy continuity in slope at the edge of the boundary layer so therefore so this will become minus a dt by dy at y equal to 0 okay so this is coming because at x is equal to y going to infinity t equal to t infinity therefore dt by dy has to be 0 okay so now this particular term again at y equal to 0 v is 0 so this will be valid number only when you look at y equal to ? t so where once again your t will become t infinity there okay so for ? t this will become t infinity okay so this is that ? t is that fine so now what we can do is once again we can integrate this by parts you can write this as 0 to ? t into d by dx of ut dy minus 0 to ? t du by dx dy okay so therefore you can combine this and this term right here so you can take t common this is du by dx plus dv by dy which is nothing but the continuity equation alright therefore I can write this as 0 to ? t d by dx of ut dy plus vt infinity minus I can take 0 to ? t t common du by dx plus dv by dy this is equal to minus a dt by dy at y equal to 0 so and this also satisfies continuity so this goes to okay and also from continuity you know that my v equal to minus 0 to if I integrate from 0 to ? t the continuity equation I can write my v velocity in terms of u velocity so just the continuity I am integrating okay so I can substitute and now I can eliminate v from this equation so if I write this in terms of u velocities this will be 0 to ? t I can take d by dx out d by dx ut dy minus I have t infinity into integral 0 to ? t du by dx minus a dt dy y equal to 0 okay so I just want to combine these two terms I can write this as now d by dx okay 0 to ? t I multiply by minus sign throughout this will be t infinity minus t so u is common for both I can write this as u dy this is equal to a dt by dy at y equal to 0 okay so this is my final form this is the energy integral equation so I can combine these two terms because t infinity is anyway constant I can take this I can write this is d by dx of t infinity u so u is common in both the cases in combine okay so now we have both of them I am going to define my ? in fact I can write in terms of ? but let me do it later so just let me write down the energy equation energy integral 0 to ? t infinity minus t u dy should be equal to a okay so this is your equation number 2 which is your energy integral okay so the first step is that we derived the integral form of momentum and energy and we have put it in this particular pattern and next what we are going to do in the approximate solution we are going to make an approximate assumption for the velocity and temperature as some polynomial okay so it can be any order polynomial and we have to see which boundary conditions that the profiles have to satisfy to calculate the coefficient of these polynomials so this is the next step so now let us take the case where we have a linear velocity profile you know that is the most basic profile that you can start with so for the laminar flow let us assume a linear velocity profile so I am just saying that my u would be something like a plus by okay this is the linear form of the velocity profile that I am assuming so in order to get the constants a and b I have to satisfy boundary conditions okay so the most you have to start with the most basic boundary conditions before we go to satisfying the more higher order boundary conditions okay the the most important boundary conditions start from the wall at y equal to 0 u equal to 0 okay and after this what should be the second most important boundary condition so once you have given at y equal to 0 you have to give something at y equal to ? okay u equal to u these are the most basic boundary conditions which are which are which have to be satisfied I cannot directly say du by dy at y equal to ? 0 has to be satisfied then it does not tell what value it should reach at y equal to ? okay it just only says that a slope is 0 that is it so if you substitute can you tell me what will be the profile that I get so if you directly substitute this y equal to 0 u equal to 0 a will be 0 at y equal to ? u will become u infinity therefore b will be u infinity by ? okay so therefore your u will be equal to u infinity y by ? so u by u infinity will be equal to y by ? so this is my linear velocity profile so if I if I plot this profile for a flat plate at any location it will show only something like this a very linear variation from 0 to u infinity at y equal to 0 u will be 0 and varies linearly at y equal to ? u will become u infinity so this will be ? something like a quad flow profile okay so this is not actually the real profile right your real profile is satisfying in a different relationship which we have seen from the Blasch's solution and definitely the shape does not look like this okay there is a slope there is a curvature terms are all there which we are not accounting for in this particular okay the slope is constant and there is no curvature so therefore this may not be a very good profile but still this is an approximation okay so why we are approximating it is once we may give this kind of an approximate profile we can substitute for velocity in this momentum integral and we can directly calculate the boundary layer thickness the expression for ? can be determined so what I am going to do now is substitute this profile into 1 so if I substitute into 1 so that I will get u infinity square d by dx 0 to ? into 1 minus so u by infinity now will be y by ? into y by ? into dy on the right hand side I have du by dy at y equal to 0 so du by dy now will be what u infinity by ? okay from the linear profile so therefore so anyway that is a constant slope it does not matter whether it is at y equal to 0 or so this is just linear profile so the slope is constant so this will be ? into u infinity by okay so very simple profile and the equation also looks simple now I am going to introduce a non-dimensional variable ? which is equal to y by ? okay do not confuse this with the similarity variable of course I am using the same variable here because coincidentally in the similarity solution also ? was the similarity variable which was related to y in ? exactly like this but here I am just using ? to represent any non-dimensional variable so if I do that I can transform y in terms of the non-dimensional ? this will become u infinity square d by dx now integral from 0 to ? will become 0 to 1 in terms of ? okay so 1- ? into ? into this will be dy by d ? into d ? okay dy by d ? will be ? so basically I can I can put this ? here into d ? okay which will be equal to on the right hand side u infinity by ? okay now this ? has to be with inside d by dx because ? is a function of your position along the flat plate so if you do the integral maybe you can take a couple of minutes and do it but since we do not have time I am just going to give you the final solution so this will come out to be 1 by 6 okay so the integral 0 to 1 1- ? into ? d ? should come out as 1 by 6 okay so in that case this will become I can cancel u infinity on both sides and this will be ? will come to this side so ? d ? by dx will be equal to 6 ? by u infinity okay so now this is a very simple OD which I can solve by separation of variables straight away okay so this will be ? square will be equal to 12 ? by u infinity x plus some constant okay this is the solution for ? of course we can find the constant by applying the boundary condition that at x is equal to 0 ? equal to 0 right the boundary layer thickness is 0 at the leading edge of the plate and therefore your constant will be 0 okay so your expression for ? now reduces to the form ? is equal to square root of 12 u x by u infinity which is nothing but 3.47 square root of u x by infinity or ? by x can be written as 3.47 I can divide by x on both sides and this will be u infinity x by ? which will be nothing but square root of Reynolds number now you can compare this with the similarity solution from which we calculated the expression for ? do you recollect what is the expression that that was 5 okay so how did we do that we calculated for different values of ? f of 0 f prime of 0 and also at all other values of ? we have tabulated and we found out the corresponding value of ? where your u by u infinity or your f prime was 0.99 corresponding to f prime 0.99 we found that ? was equal to exactly 5 and that is nothing but the value of ? okay so this is how we have got it approximately the actual solution is ? by x is equal to 5 by square root of rex so since we are using an approximate profile this is the variation you know so this is about 31% less than the exact solution okay so there is an under estimation that we get by using the linear profile and we can go ahead and calculate the wall shear stress local variation which is ? du by dy at y equal to 0 okay so in this case du by dy at y equal to 0 is nothing but for the linear profile u infinity by ? okay so this is ? u infinity by ? so we have already got the expression for ? which will substitute here and if you do that you will get 0.288 u u infinity square root of ? u x okay so now if you define non-dimensional local skin friction coefficient as ? by ? infinity square so this will come out as 0.576 by square root of Reynolds number okay so and if you remember the exact solution was giving 0.664 okay so this is about 13% less than exact solution okay so if you also go ahead and integrate the local skin friction coefficient over the plate and calculate the average skin friction coefficient for the entire plate that is your CFL is equal to 1 by L 0 to L CFX dx okay so we will end up with expression 1.152 by square root of REL okay so finally the bottom line is this you can you can get an approximate estimate of all these quantities like boundary layer thickness your local shear stress in friction coefficient everything using some approximate profiles and this is much much easier as you can see than doing a rigorous solution to the similarity equations okay and in fact if you use a better profile you will be amazed to find that the agreement will be even better okay so just to give an example if you go from a linear profile to a cubic profile okay which I will just show you and stop there okay so if you assume a cubic velocity profile u is equal to a plus BY plus CY square plus DYQ okay so now you have 1, 2, 3, 4 coefficients and we have to satisfy therefore 4 boundary conditions so what are the possible boundary conditions y equal to 0 u equal to 0 and at y equal to ? u infinity so these are the important boundary conditions and what is the next important boundary condition at y equal to 0 ? u by ? y so if you if you look at the momentum equation okay so u du by dx plus v du by dy is equal to nu d square u by dy square at the wall okay both are 0 so therefore d square u by dy square has to be this is the next important say in the order of importance I am writing it okay and then finally what is the last boundary condition that you have to give cubic in terms of the order of importance okay so these are most important and then at y equal to 0 this is to be given and then y equal to what ? okay so these are the 4 important boundary conditions so if I substitute these boundary conditions into the profile and you calculate all the coefficients finally I will be able to arrive at an expression which is like this u by u infinity will be 3 by 2 y by ? minus 1 by 2 y by ? the whole cube okay so this is the cubic velocity profile that you will get I am sure most of you have taken the heat transfer course have done this also in advanced heat and mass transfer in incompressible fluid flows okay so cubic profile is like the accurate profile that you can do okay so once you get this and if you substitute the same way that we did the linear profile into the momentum equation so let us see what happens to the final expressions the final expression for ? that comes out with the cubic profile will be 4.64 that is the correct ? by x will be 4.64 by ? root of rex so you can see a remarkable improvement okay so this is like 7% less than the exact solution and when you look at the skin friction coefficient so this value comes out as 0.646 by ? root of rex this is like almost there 3% less okay so this is 0.664 this is 0.646 almost there so you can see that with the cubic profile you get a very good approximation very accurate solutions okay rather than going for a very rigorous similarity solution so nowadays I think many of the people they are not so interested in the similarity solution because you have numerical techniques where you can directly solve the governing equations okay and or you can also resort to solutions like approximate methods with the integral equation where you can make use of some approximate polynomials and also get the solution so that is why these are more popular methods okay which are also workable in a very short time but the you have to be cautious that does not mean that if you keep increasing the polynomial now this accuracy will become better and better okay so for example if you go from linear to quadratic and from quadratic to cubic you will find that it does not progressively increase in terms of accuracy okay in fact quadratic in fact spoils the solution a little bit that is mainly because in the case of quadratic boundary conditions we give this boundary condition this boundary condition and finally this boundary condition we do not give this particular boundary condition okay so because we have only up to here we do not give up to this boundary condition because of that you will find there is a D generation in the accuracy the quadratic case again with the cubic it satisfies all the fundamental boundary conditions and the accuracy goes up and if you use a fourth order polynomial again you may have to give something like y equal to delta d square u by dy square equal to 0 you have to introduce higher derivative basically and they may not be very important so therefore you may not get no the error may not come down all the time so that is why maximum you go to cubic and we can stop there okay so in the next class tomorrow we will make an approximation for the temperature profile the same way that we did and we will substitute into the energy equation and calculate the thermal boundary layer thickness and therefore the heat transfer coefficient okay so we will see these aspects in the next class so quickly we will move from flat plate so flat plate I am sure many of you have familiar with the heat transfer course so we are not going to spend much time we will do this analysis for flows with pressure gradient similarity flows is that dealt with in the other courses or no where you have done similarity solution for adverse pressure gradient flows or pressure gradient flows I am sure something must have been done in incompressible flows the Thwaites method Thwaites method and Carman-Pollhausen method okay so maybe we will cover those aspects in the future next four or five