Everybody forced here. I'm a rip in twenty twenty two tops pristine baseball hobby eight box case number 39 it is a picker team case Adam L. Red Sox Albert W Mariners Benjamin V. D. backs Brian R. with the Yankees Chris B. Orioles Eric T. Pirates Padres Ray's Cardinals Howard Z. Guardians Rangers Jacob S. Phillies James M. Mets Johnny B. A's Jordan W. Dodgers Kizzo Giants Kirk Angels Matt P. Royals Yeah, Matt P. Royals Michael P. Tigers Nicholas H Rockies Twins Robert F. Reds Sean S. Astros White Sox Ship my cards Brewers Steven W. Blue Jays Cubs Nationals and Braves in Thomas F. with the Marlins. Thanks everybody for joining and good luck We're gonna fill up. We got tier one PYT is coming up next with a bunch of teams on sale guys Got three tier one after this and two definitive and then to close out the afternoon the daytime breaks. We've got Top's finest wait for Champions League dude. I'm excited for that Yeah, definitely Dean. I'll be awesome man. We're pretty close to Orlando only what Yeah, half hour We are not that far Family hotel estate outside of Disney I'm sure there's a ton. I honestly don't have to top my head If you're not trying to say it like a Disney resort, I honestly don't know There's a like I went recently like to downtown Disney drove through it and there's a billion different There's hotels everywhere there if you want to go a little farther. There's just hotels everywhere, man. Yeah It shouldn't be too tough to find that time of year either Remember, it's not the busiest Let's just Thanksgiving time Guys, good luck MP It's your Detroit Detroit PC going strong Two of the Detroit goats There you go. No offense. It's not a lot of Detroit goats. I guess There's a few It's hockey you got a problem. Yeah, Stevie. Why? Chellios Yeah, I'm just gonna what would you do if you had 10k shopping street? I Probably do like five can last Did I do like one I probably get like a definitive box. I was gonna say how I would rip it I would rip a definitive for sure Definitely Over that good. Yeah, it's under three for sure, but Get one of those Yeah, and my five can wax. I do half to one Like half of the 5k we go one box by definitive and then the other ones I do like I want a couple UFC selects Maybe like football Something like that The fund right here already Can't be right 11 a.m. Yeah guys for to go into your one next that you drop that way Got a cunea pristine boarders braves Don't like the packaging I Keep saying this like everyone else doesn't like it, but like I'm used to it now and I Don't mind it got my inner very honestly kind of like opening it now. I don't know so weird to say I was thinking that but it's also just like if you like opening packs. It's an awesome product It's a great product You just got a bad rap just because at first it was like it was like shock factor at first There's like what is going on here pure power of laddie for the blue jays? No, I like this product. I bought a few I bought a decent amount of Red Sox singles Just look fantastic Freddie Freeman you got the encased hits as well I All right our refractors now George Brett's I see a red coming up later Shorber Maze Jose Siri rookie refractor for the Astros. He's on a raise now, right? You Joe Ryan rookie for the twins purple Strasburg Washington 57 and 99 Don't gold braves Jersey Otto John Smalls one of the last teams to sell. Hey go Braves Always go 36 of 50 you were saying it's him Sam was saying they always hit it was the first one we got to That's the Oscar our red is for the Dodgers. It is max Muncie red refractor five out of five Congrats Dodgers good starts in this case Jim told me as a Philly and Alex for do go all of the encased cards now Brewer's gold Corbin burns nice brewers color match 15 of 50 Chris Bryant not numbered refractor White Sox not numbered Otto Eloy Jimenez a pink refractor Royals Andrew Benintendi eight of 15 nice pink That one's a little shifted to the left. You can kind of see but the not moving so we're gonna leave it alone blue for the angel Shohei Otani nice blue Shohei 28 of 75 and Tigers Otto Casey Mize Yep top 100 I guess I'll put like a description in there Yeah, top 100 so when you open the results on the website and just has those those first 100 there without everything else Those are the winners Who is a thick pack man? That's a thick card. That's a thick card. Oh boy The anticipation is already The urge to just look at it right now No, not really I mean we can find all the decent chains. I don't have like a Our recommendation You're gonna get what you pay for I think for the most part so you're just like a mid like Like a mid tier like three-star hotel or you can get like breakfast and Decent rooms and stuff decent location 25 minutes It was crazy the national What is going on? Okay this patch you didn't encounter any packs like this. I had one where I think was completely huge Not entirely sure when the boxes will ship That's fine.  So will is our is one of our shipping managers. He's probably the main shipping manager wonder Franco Yeah, I would definitely give it. It's not gonna happen today.  Yeah, we should try I just I don't think he'll box the work. I think right Dispective ever come out of here Anyone in chat where for spectrum Do you want to be in your piece for a minute All right refractors now get that big it's gonna be a big patch out on the back here Beaver Riley Brian Reynolds purple refractor one Gonzalez Rangers that one's out of 99 18 of 99 Rangers refractor rookie Pirates Hoyt Park and Manuel Rivera Royals refractor Jake Berger white socks rookie refractor Ralta Griffin Jacks for the twins purple rookie for the Royals a manual Rivera that is out of 99 as well 58 of 99 Byron Buxton and orange. It's gonna be to 25 Red Sox Raphael Devers bat relic auto one out of 25 nice Robbie Devers Sweet hit Red Sox peanut butter and jealous It's a nice hit orange refractor brewers Paul Molitor 19 of 25 pile see your non-numbered Reggie Jackson a's pure power insert auto nice hit a's Willi Adam ace blue refractor brewers 30 of 75 Austin Riley on the non-numbered refractor and twins auto Tori Hunter non-numbered Nice box there. I guess I'll go put on the post like Yeah, I tried but get peacocks. I can watch soccer Premier League we got What do we got in tier one next White Sox Red Sox Dodgers Pirates left on tier one case breaking next guys Should be a all-on sale on all the tier one cases Got three of them coming up after this pristine You got definitive baseball teams on sale as well and some tops finest Champions League Random team styles to close out the daytime And to start the nighttime, I think Should be fun release. I'm excited to see finest I think it's last year's design. I'd be a last year release You Darvish Miguel Cabrera pristine borders Gold Yankees pristine borders Mariano Rivera That is 18 of 50. There you go Yankees Last spot Gold refractor there and pure power Raphael Devers Red Sox inserts refractors Eskibar Bogart Santheon Frasier Contreras purple Rockies color match Charlie Blackman 32 of 99 Kyle Seeger gold refractor Red Sox Nathan of Aldi 42 of 50 Kyle Lewis Aaron judge Dylan Carlson and an orange refractor Joe Morgan Reds two of 25 Hope it isn't right on my way home. One of my winch wipers is like off Like it's like there's not even that old and it just like Detached completely Like it broke at like the seal part. So I'm like, okay. Well, what does it rain? My windshield is gonna go scratched up got orange rookie Nationals Josiah Gray 18 of 70 or 18 of 25 Gary Sheffield Marlins Adolas Garcia Rangers pure power insert auto not numbered. Okay for let me check that out right after this actually blue Carson Kelly 35 is 75 Max Scherzer refractor Dodgers and Jackson car rookie auto Royals not probably just had clicked on the wrong one Something happened for yeah I'm gonna check that out after actually I have no idea that order might be off. That's what I'm thinking I mean the results are up That's very weird. It's also the very beginning of the stream. So if you just rewind at the beginning you can watch it How'd you guys do yesterday? You just go through it at the same time. Yeah All right base packs With y'all Bruhan rookie insert Tampa Bay pure power hobby bias as a met All right pure power tautis. Yeah guys the video should be correct now She'll must be done uploading actually Yep, it's uploaded The results are also posted elitonsportscards.com quick results or results quick link down at the bottom Page we've been dropping the link every few minutes or so max Kepler Rosa reina refractors now Sanchez got gold max Muncie Dodgers 13 of 15 Karoo poppy al-tube a bray you sure as a Dodger gold refractor cubs Ron Santo 38 to 50 Gallon purple wander Franco raise rookie Nice one there 94 of 99. We're gonna get that one mag for you Tampa Bay beautiful wander Bregman and bat relic auto max Kepler For the wins non-number here you go 20s gold trade Turner Not gold sorry orange trade Turner better than gold 25 of 25 Dodgers Jake burger rookie refractor gold popular demand auto Astros Jose al-tube 44 of 50 Nice al-tube blue refractor white socks Frank Thomas 28 of 75 a non-numbered refractor Jamer Ken Lario redemption pristine parallel auto of O'Neill cruise Pirates boom Big hard Pirates, I think the pristine parallels should be to 99 on the rookie auto Who had Pittsburgh dude is crazy. They were showing like top five sprint speeds and he's in the top five. He's six foot seven Eric T congrats on the O'Neill cruise Good box for rookies there. So that one should be Totally good to go now. I don't even know how I did the wrong one. I honestly don't know Tier one breaking next guy's three teams to go Red Sox Dodgers Pirates Red Sox Dodgers Pirates Maybe a chance at O'Neill cruise just pulling out of pristine He's alive in tier one Red Sox always have a good amount of hits and basically every product I want to say especially when it's like that focus the Dodgers always have like Walker Bueller A lot of that stuff. You have Andre Jackson rookies or the Dodgers They'd be dodging Got pure powered Jesse winker for Cincinnati Josh Chesham, Jose Bray you've got finest Champions League as well later guys Random team style those had some spots to go O'Neill cruise base rookie for the Pirates now Brian Hayes inserts Also a few weeks time. We'll have a new latent baseball channel I think it's just just Matt breaking baseball four or five days a week Awesome, and we'll still do baseball in this channel, but a lot of the base heavy baseball be done with Matt now pristine borders Ichiro Mariners refractors now I got Walsh Trammel Mariano Rivera purple refractor Braves Chipper Jones 94 of 99 Muncie blue jays slice of a star jersey out of T. Oscar Hernandez pristine refractor 62 of 99 the hockey channel I mean we I mean we post hockey breaks when people want us to post hockey breaks and they always take a long time to fill They filled up quicker. I'm sure we could you have a hockey channel got orange refractor Yankees Glaber Torres 22 of 25 Herman Marquez and Jonathan India would be all hockey Love I wish we could break it more Gold rookie Tampa Bay Wander Franco 6 of 50 There you go rays now or again, I should say had the purple last Last box beautiful gold Wander Got a Adam Frazier Padres Nolan. I ran out of Cardinals not numbered auto Blue it's a tease for the Padres 63 to 75 he's he's getting close to being back man. He's looking pretty nasty in triple A to Anthony Rendon and gold refractor auto a is nice color match Matt Olson 8 of 50 Another good box. I mean he should be looking good in triple A, but he like doubled in triple like this first game They might be the most fun team to watch in baseball When they're when they're healthy, I think it might not be that close either as far as fun I'm not saying they're the best but as far as like Hattis is probably the most fun player to watch Period we did break a good amount of SP authentic For the national I love SP authentic So much The team names are there for the PYT's so it also has the break name next to the team so in random teams you'll have the Random styles, I guess it could be random teams random division whatever it was random hit It'll have the name of the person in the break for PYT's. It'll have the team of the break But that's why the break is next to that team So get the Tigers in Tier one case 30, you know, it'll be listed like that Kellnick, yeah But yeah, super important for us to have the break names exit would be it would should be in such a big promo That way, you know There's probably so many Matthews and Michaels and John's and Kevin's or whatever so having the The name the the break title next to it is key There's some of them were abbreviated so it might be a little bit tough But it should be fairly clear it should be pretty different from the other the other breaks You know what I mean pure power Aaron judge Yankees, but that's just so We can't put the full break title wouldn't fit in the randomizer Okay, I think it's like a 75 character limit per line. I think on the randomizer Ran into that with the Super Bowl promo Once or the other the weekly football mixer promo Max Kepler again, we've got refractors now Sammy Long rookie giants Paul de Jong Manuel Rodriguez Ted Williams Kellnick Miguel Cabrera for the Tigers a Gary Sheffield a gold refractor Aaron judge There you go Yankees 18 of 50 Last team's taken man. I think it was the last team got Torrey Hunter purple refractor blue jays boba shits 95 of 99 Austin Meadows and slice of a star Bo Jackson White Sox Jersey auto Bo Jackson white Sox I Am completely caught off guard right now Look at that. I did not I did not know he was a white Sox in this. I think he's also a royal Incase like auto yep Nats. We're just talking about his new team Nationals one Soto auto 71 of 99 Big card Nationals Steven W. Congrats on hats gold refractor Brewer's Freddy Peralta It's a 50 non-numbered Peralta a Sammy Long Giants rookie auto non-number Jared Kellnick blue refractor mariners 30 is 75 and a non-numbered kershaw more boxes What's up Ryan is is good The case has been very good hard every box. I feel like it's had a really nice hit at least at least one I got to keep this this momentum rolling guys cuz I'm very tired I did one of those things where you sleep 30 minutes and wake up for like an hour and you sleep 30 minutes to wake up for like an hour I Played that game last night. I had three sips of coffee this morning Taco Bell breakfast Feel like I'm in college. Didn't get any sleep, but also didn't accomplish anything I'm not even gonna complain about that. That's just how it be sometimes you all got them days But breaks have been pretty good so far I'd say There's only second one, but We still got tier one teams on sale everybody Finest champions league and definitive baseball on sale PYT is on the baseball or random teams on the champions All right base packs here got pure power Jose Ramirez Cleveland in the insert Pure power griffy for the Mariners Sharon Durand rookie Mariano Rivera Miguel Cabrera pristine boarders Tigers Shohei Otani pristine boarders angels Mariano Rivera pristine boarders Yankees refractor rookie Greg Deakman Cubs Jersey Otto popular demand for the twins Byron Buxton Non-numbered on the Buxton Jersey Otto Sander Bogart Seth beer rookie refractor for the D-backs Furlander Duke Snyder Crawford Gold refractor A's Matt Olson three at 50 Tom Siever another Jersey Otto Geo or Shella Yankees Non-numbered Geo or Shella Jersey Otto Yankees Joe Maurer purple refractor Red Sox Ricky Connor wall 78 of 99 Red refractor Red Sox Raphael Devers four of five sick raffy Congrats Red Sox big one there on the color match Got gold auto Mariners Jared Kelnick 17 of 50 blue for the Reds Barry Larkin Two of 75 gold brewers Paul Molliter 23 of 50 Rookie auto Tyler Gilbert D-backs non-numbered and a redemurs rookie refractors an extra hit in that one So there may be one less in his last box Unless there was one less before I just didn't notice But I don't think we've had a full case of pristine with less or more Hey guys tier ones breaking next three teams to go there on sale Red Sox Dodgers Pirates, right? Red Sox Dodgers Pirates. I wonder if he actually fell off a bike I'm interested if you actually call a biker that's just like I might not be something you make up though So I'm wondering if he actually fell off a bike with that's just like a PR thing But it seems like we're gonna make up I guess Yeah, I was gonna say maybe he was like throwing TVs or something I miss 2016 or 2018 for sale a guy that's 300 strikeouts in a season and didn't even make every single story good He still has the highest strikeout to walk ratio all the time. Really just insane He was like crazy good like he was so good though White Sox and then for for like three years the Red Sox he was just yeah when he was healthy just on on touch Yeah, it's not only like baby every year This those days We got a world series out of the film. Yeah close out That's what you're closer all time He did close one out didn't he I think that was 14 right You really carry them that year. All right, Jose, brave What's going on Vaughn you think the Red Sox is split with the Braves? They definitely can they lost an action last night Gold of Lattie Jr. Pure power insert blue jays 28 to 50 last base pack of the break pure power Mike Piazza Mets Flash refractors here. You're Stremsky Red Sox you're Stremsky slice of a star Jersey auto Astros Jose Altuve non-numbered Joseph like always hit Lisa and Altuve or Bregman or something Cutching purple refractor blue J. S. T. Oscar Hernandez 27 of 99 Anager Soto Machado purple refractor Braves Austin Riley 85 of 99 Bryant Detmer's Candelario gold refractor Astros Chasmic Cormac 11 of 50 Yeah, if the bet is pitching it's seven one hit innings or Seven hit one inning It's either reversed Four walks 11 earned runs Cleveland auto Shane Bieber non-numbered blue refractor Mets Francisco Lindor 2375 20 Suncie on a rookie Gold Hank Aaron Braves I 750 Gary Sanchez and Ryan Sandberg popular demand Cubs auto non-numbered. Let's do a quick recap really good case Thanks for filling it up everybody. Here are the non-incased relic autos Jose Altuve Gio Rochella Byron Buxton bow Jackson as a white socks T. Oscar Hernandez max Kepler orange Rafi Devers So Red Sox Red Sox had two nice Devers this break gold John Smoltz for the Braves Incased autos Ryan Sandberg Shane Bieber Tyler Gilbert Jared Kelnick gold auto a red Raphael Devers Parallel five-of-five Sammy long he won Soto to 99 Nationals gold Matt Olson Nolan Aronato, O'Neill Cruz pristine parallel auto pirates redemption Great break gold out to Vita 50 Jackson co-ar Adolas Garcia Tori Hunter Reggie Jackson KC mice Eloy Jimenez Get a gold max Muncie to five for the Dodgers Purple rookie wander Franco to 99 and gold rookie wander Franco to 50 Like I said guys really good case. We've got tier one coming up in just a few


So, let us move on to the final phase of radiation that is radiation 5 that is okay. So here we have 3 wall enclosure, so if I go to 3 wall enclosure, so what are the, see one important thing, another important thing which we need to realize the resist electrical resistance analogy between radiation and induction. When our students in our NSM made a mistake in this that is especially we have to be careful when I have a conduction radiation combined problem remember in radiation the potential is emissive power and radiosity and in conduction the potential is temperature. So I cannot combine conduction and radiation problem both the resistances that resistance in conduction is having potentials of temperature and the current is heat flux no problem here also current is heat flux only but the potential is emissive power we should not forget this. This is the basic difference between the electrical resistance analogy in radiation and conduction. This is where we get into trouble usually when we have conduction radiation combined the problem we get into trouble we had unknowingly we had given a problem in the NSM and 50 percent of our class had goofed up this problem by combining the resistances that is why I am mentioning this okay. So we have now potentials what are the potentials one can conceive of eb1 j1 okay I will not construct this first eb1 j1 then eb2 j2 eb3 j3 why am I doing this because I have three surfaces I should be having three surface resistances. So those three surface resistances are 1 minus epsilon1 epsilon1 a1 1 minus epsilon3 a3 1 minus epsilon2 a2 epsilon2 so I have three surface resistances. Now these radiosities j1 j2 j3 are interacting with each other that is j1 is interacting with j2 and j2 is interacting with j3 j3 is interacting with j1 with individual space resistances. So j1 has to interact with j2 means what is the space resistance between 1 and 2 it has to be 1 upon a1 f12 or a2 f21 so I have this is 1 upon a1 f12 okay the space resistance between 1 and 3 is 1 upon a1 f13 and the space resistance between a2 f23 is 1 upon a2 f23 that is all. So it goes logically now what am I doing is I am applying Kirchhoff's law if I apply Kirchhoff's law this time Kirchhoff's law is not the Kirchhoff's law for radiation Kirchhoff's law for electricity okay for electrical circuits so that is V equal to voltage equal to current into resistance that is all I am applying. So what is that let me go through this that is I take three nodes j1 j2 j3 node at each node I say that the input current whatever is coming is the summation of the current is 0 the algebraic sum of the currents at each node must be 0 that is all current means what here it is heat flux so EB1 minus j1 upon R1 current has to flow in this direction so this has to be that is the direction assume it may be wrong if it is wrong it will come out as negative so I do not have to worry about that I think we have done this in electrical circuits I do not think I need to harp this again so EB1 minus j1 upon R1 plus j2 minus j1 why because current again has to go towards the node j1 and plus j3 minus j1 upon R13 so that is equal to 0 similarly if I do for j3 and j2 I am going to get three equations so total how many equations I have three equations typically if I know the temperature if I know the temperature of these three surfaces emissivity that is what I have taken I have taken that emissivity is known surface area is known and temperature of the body is known so I get if I know the temperature of the body what is EB1 sigma T1 to the power of 4 sigma T2 to the power of 4 sigma T3 to the power of 4 so I know EB1 EB2 EB3 do I know R1 R12 R13 yes because 1 minus epsilon 1 epsilon 1 A1 and 1 minus epsilon epsilon and A s are known means known means R1 R2 R3 I know that is surface resistances are known do I know F1 2 F1 3 F1 4 sorry F1 3 F1 F2 3 and F what is the other one F1 2 do I know these three I can compute from the geometry I can compute this this is not an issue so if I come that means I know all resistances I know all emissive powers what are unknowns then in these three equations j1 j2 j3 I have three equations three unknowns if I solve them I will get j1 j3 j3 okay so from there there is a problem here I do not think I need to spend time on this problem do you think this problem I need to solve because it is just yeah if time permits we will come back to this but actually in a you have a cylinder the top surface is one bottom surface is two and the circumferential surface is three so I have surface 1 surface 2 and surface 3 1 and 2 are having emissivities of 0.8 and 0.4 3 is having an emissivity of 1 it is black and temperatures are 1 is 700 and the bottom wall is 500 and the circumferential surface circular surface is 400 Kelvin so I can whatever I just derived the same circuit is valid okay so because there are three surfaces it need not be triangular only as long as there are three surfaces whichever shape you can think of that is applicable okay so if you put that so if you just take that and you have the equation that is eb1 – j1 eb1 you know eb2 you know eb3 you know okay and 1 – eb1 these three you can compute okay and now all that you need to do is you have to compute f12 f13 and f23 f11 is 0 okay because what is 1 the top surface 1 is f11 is 0 now you get f12 and f13 how do I get f12 that is top surface to bottom surface 1 to 2 it is a function of ri and rj that is the radius of the top surface and the radius of the bottom surface and the distance between the two surfaces so that is ri, rj and s if I plug in all this in this relation you are going to get 0.38 so you get 0.38 as f12 now you will get f13 as 0.62 but you need f31 so how do I get that is I will put reciprocity rule I get f31 equal to a1 f13 upon a3 you get 0.31 so now you got f12 f13 and f31 do I need anything else that is it that much is sufficient for me so now if I go ahead and substitute for and do I need yeah why have I not done f23 here f13 and f23 are symmetric by symmetric rule f13 and f23 are same that is why I have not set up or I have not completed again f23 separately is that okay so now if I substitute all these values I am going to get 3 equations and I am going to get j1 j2 j3 having got j1 j2 j3 this is important step yeah this problem has relevant in this step otherwise you may miss that that is q dot 1 equal to a1 into f12 j1 minus j2 plus f13 into j1 minus j3 how did I get this from this okay that is j1 minus this is the net heat flux see one is interacting with 2 and 3 so j1 minus j2 if I take j then I do not have to take the space resistance sorry surface resistance and if I take 1 and 3 I do not have to take if I take j1 and j3 I do not have to take the space resistance again for 1 and 3 so that is what I have done here so a1 j1 minus j2 upon 1 upon a1 f12 plus j1 minus j3 upon f13 plus j1 minus j3 upon 1 upon a1 f13 that gives me 27.6 kilowatts similarly for q2 I get minus 2.13 kilowatts and q3 I get minus 25.5 kilowatts so the net heat flux should be the algebraic sum of all this should be 0 the net heat transfer that is by conservation of energy so you get q1 dot 1 that means it is getting what is that what is happening q dot 1 see you see the temperatures you will be able to understand the temperature t1 is at higher temperature t2 is at lower temperature and t3 is till lower temperature so q12 that is q dot 1 what is happening q dot 1 q dot 1 is coming out to be positive that means it is it is radiating heat q2 is receiving heat and q3 are also receiving heat that is the interpretation of plus and minus side with this we will there is another problem here in which what we have done is another important concept here is insulated if it is insulated heat flux is 0 if heat flux is 0 eb3 equal to j3 so with that if you I think you are able to see that so with that I will move on to next concept called radiation shields so this I will be going really breezing through so let me see how fast I can go so here I have one surface I have another surface I have mentioned this already in case of super insulator in while building super insulator so these are eb1 and eb2 if there was no shield I would have had 1 minus eb1 eb1 a1 1 minus eb2 eb2 a2 but now I have a shield so the resistance between these two space resistances 1 upon a1 f13 here space resistance is 1 upon a3 f32 now what is this surface resistance on this side that is 1 minus eb3,1 the side which is facing 1 is called 3,1 the side which is facing 2 is called 3,2 1 minus eb3,1 upon eb3,1 a3 and 1 minus eb3,2 eb3,2 a1 so these are the two resistances which are added because of adding the shielding material and if I play with my epsilon properly I should be able to arrest the heat transfer from one surface 1 to surface 2 if I have to have this resistance what should be my epsilon low or high low if the epsilon is low that means my resistance will be high if epsilon has to be low means typically reflectivity has to be very high transmissivity is 0 so reflectivity has to be for shielding material you have to again use aluminum foil I am going back to my chapati example so that is why we use aluminum foil because we are using it as a radiation shield. So these are the resistances so I have taken if I take a1 equal to a2 equal to a3 and f12 equal to f32 equal to 1 the above equation reduces to this so if there is no shield I would have had this heat transfer if there is a shield this is the additional resistance which is coming to picture now if I have n shields if I have n shields these many n shields will be n resistances should be added up those resistances are this so q.12 with 1 shield equal to 1 upon n plus 1 into q.12 no shield under the condition that epsilon 1 equal to epsilon 2 equal to epsilon 3 comma 1 equal to epsilon 3 comma 2 so only says that if I use 1 shield the rate of the radiation heat transfer has become half if I use 2 it becomes one third if I become if I use 9 shields it becomes one tenth like that if you have infinite shield if I infinite number of shields there should be no heat transfer radiated to the other plate that is precisely what we are doing in super insulator. So with this radiation shield concept I know I have gone very fast but I request you to go through these steps there is nothing great in this it is just putting resistances so there is nothing great in terms of concept there so I request you to see and there is a problem again setup when there is no shield you have 3 6 2 5 watts per meter square when you have a shield you get 8 0 6 watts per meter square because emissivities are different now you can put in excel sheet and play with these emissivities and see what happens to heat flux. So now an important concept I want to touch upon before we move on to tutorials so that is radiation effect in temperature measurement why I am wanting to emphasize this more because we always believe that if I put a thermocouple or a thermometer anywhere it is going to give me a temperature not so under what conditions the thermocouple and thermometer is going to be representative of the temperature what I want to measure that is very important how will I get that so now let us just take a thermometer or a thermocouple which is inserted in a pipe okay which is inserted in a pipe what is that I am doing I am doing energy balance for this thermocouple bead or the thermometer bulb that is there are I am neglecting conduction so convection see what is happening here there is thermocouple which is going to show the temperature and fluid is having its own temperature which is what I want to measure through thermocouple and wall T wall is the wall temperature it is having wall temperature what is that it is happening I am assuming that the fluid temperature is very high fluid temperature is very high and wall temperature is definitely lower than the fluid temperature and thermocouple has to pick up the fluid temperature okay so now the heat transfer is from fluid to the thermocouple fluid to the thermocouple and there might be some radiative heat transfer between the wall and the thermocouple now if I set the energy balance between the thermocouple or the thermometer between the thermocouple and the thermometer and the fluid and the wall what is happening convective heat transfer has to be equated to the radiative heat transfer that means whatever the thermocouple is receiving heat by convection it has to be balanced by the radiative heat transfer between the thermocouple and the walls of the pipe how do I do that heat transfer convection heat transfer coefficient into Tf that is the fluid temperature minus T thermocouple T thermocouple that is thermocouple is not going to show the same temperature as the fluid there is a temperature difference why why because there is convective heat transfer coefficient that is H there is a heat transfer between the fluid and my thermocouple or the thermometer now that should be equal to epsilon thermometer that is you see here I had mentioned this when I inserted a small pressure around I had given as an example when I put a tennis ball in this room what matters is the emissivity of the tennis ball not the emissivity of the walls precisely that is what I am doing here that is here the radiative heat transfer I have taken the emissivity of the thermocouple only it does not matter what is the emissivity of the pipe wall assuming that here what is the assumption I have invoked is that my thermocouple bead or the thermometer bulb is very much smaller compared to the pipe size or the cavity in which it has been enclosed so that is epsilon of the thermometer or the thermocouple into sigma into T thermocouple to the power of 4 minus T wall to the power of 4 now let us rearrange this little bit little differently that is I get T f equal to T thermocouple plus epsilon thermocouple into sigma T thermocouple to the power of 4 minus T wall to the power of 4 upon H so you see ideally what is that I am expecting whenever I insert a thermocouple I expect that my thermocouple is going to show the fluid temperature not always so why because of this correction term when will fluid temperature be equal to thermocouple temperature or the other way around when will be the thermocouple temperature equal to the fluid temperature when the heat transfer coefficient is very high only for high speed flows high speed means not a very high speed what I mean is when the velocities are reasonably high for example air velocity is let us say around 3 to 4 meters per second the heat transfer coefficient between my thermocouple and the fluid fluid which is flowing over the thermocouple only when H is high that is for example if the water is flowing this radiation error radiation effect error will be very small but if it is air and the velocities are low H will be low then this error will be very high so or the deviation error may not be the right term the deviation would be high so if I have to keep the deviation low I have to keep this H high and the epsilon that is the emissivity of the thermocouple has to be as low as possible if I have to keep the emissivity low means what should I keep what should I what what can I control I can only control reflectivity all solid surfaces as I said transmissivity is 0 if it is highly flashing reflecting surface then reflectivity is high and emissivity is low but that is not always possible to maintain because once I insert it if there is a fluid it gets rusted then naturally that glaziness is lost and it becomes diffuse so you have this deviation we need to take note on I think I think we have 5 more minutes so we I will just quickly give you the feel of this deviation or the error not error is the right term although I am I am just using it just for the heck of it I will just give the feel of the deviation with the numbers I have a problem in which wall is maintained at 400 Kelvin and the temperature reading that is the thermocouple has is 650 degree Celsius who has given some thermocouple reading is 650 what is that I am looking for I am looking for fluid temperature and the emissivity of this bead is 0.6 Kelvin so now if I plug in this here and of course heat transfer coefficient has been given 80 watts per meter square degree Celsius it is significantly high it is not natural convection it is forced convection and I we can take this number as for air may be around 4 to 5 meters per second so if I plug in these numbers and with the thermocouple temperature as 650 Kelvin and wall temperature is 400 you see what is the deviation I get 65 degree Celsius if the H is low let us say I am taking a still room and H is low means we said that in under natural convection conditions H can be as low as 5 to 10 10 watts per meter square degree Celsius if I put in 10 if I put in 10 here what will happen 8 times my deviation will go up that means 65 into 8 so imagine the deviation between the fluid temperature and the thermocouple temperature so the point what I want to emphasize is that not always when you insert a thermocouple or a thermometer anywhere and everywhere it is going to measure the temperature what it is intended for that is the point what we want to drive home here if it is a low velocity flow or a natural convection most of the times measuring accurately the temperature is not an easy task so we need to keep this in mind because you may think that I will go ahead and measure I will try to go ahead and try to quantify this H and try to quantify this epsilon and make the correction most of the times it is just not possible simply because I will not be able to compute this H and epsilon thermo epsilon thermocouple that accurately and also it varies with I mean it changes with epsilon especially changes with time so there are various ways to circumvent this problem let us not get into that but for now what is important is there is going to be deviation where in which you have to control H and epsilon.