Ukrainian Defence Forces make successes south of Eurasian consolidate their positions. Ukrainian Defence Forces continue their offensive in three directions and have succeeded south of Eurasian and are consolidating their positions. Andrey Kovalev, a spokesman for the General Staff of the Armed Forces of Ukraine, said this. Ukrainian Defence Forces continue to conduct offensive operations in the Bakhmut, Melitopol and Burdiansk directions. In the direction south of Eurasian, they have succeeded consolidating their positions, conflicting artillery fire on the identified enemy targets and carrying out counter-battery measures, he noted. According to the spokesman, in the Bakhmut direction, Ukrainian defenders continue to conduct offensive actions south of the city of Bakhmut, consolidating the achieved positions. At the same time, he emphasised that Russians conducted unsuccessful offensives in the areas of Abdiivka and Marienka, adding that the enemy suffers significant losses in personnel, weapons and equipment, moves units and troops and uses reserves. Kovalev also informed that the Ukrainian Defence Forces continue to hold back the Russian offensive in the Kupiansk, Lyman and northern flank of the Bakhmut direction. As reported on August 16, the Ministry of Defence of Ukraine announced the liberation of Eurasian in the Donetsk region.


excuse me mommy I see you are eating I know I ate twice today but don't you think you should give me more how can you resist this face look how cute I am


Bollywood superstar Manav is at the peak of his fame when tragedy strikes. Now this actor has to play action star for real. Yeah, that happens a lot in the movie. Let's talk about an action hero. Ayushman Karan is the main star here. He does a great job playing Manav, a self-centered actor who's at the peak of his fame. He surrounds himself with incompetent yes men. He brags about his money, which to be fair, he had very little starting out. He genuinely did rise to the top by being a great actor and struggling along the way. So the guy is layered. He's self-centered on one hand, but he's also trying to do the right thing on the other. That is, until his character and his entire career are on the line because of a tragedy that takes place, which I won't spoil. I'm not gonna go into the details because I went into this film blind and the reveal there was by far the best part of the film. It actually, like, hit me hard. I was like, oh, wow, I did not see that coming. Where is this movie gonna go next? And unfortunately, where it does go next is kind of your standard born identity stuff. I found myself liking this film, but not loving it. It's called an action hero, but there isn't a lot of action for a good amount of time. We have a bit of a slow burn until the later act. And once we get to that final third, things go kind of wildly in a different direction than I was expecting. And I just sat there kind of scratching my head for a while thinking, what, how did we get to this point? Manav's gonna find himself on the wrong end of the law. He's gonna have to go on the run, flee the country even while the cops are in pursuit. They're not the only thing that's a threat to him, though. The main threat in the picture is Bora, a man with high influence, deep pockets, and a really fragile ego. Something we all see every day in the real world, and it's not a good look. Jaideep Alawat plays this antagonist, and I have to say, he looks the part, he acts the part, but some of the writing makes him come off a little too silly at times. It's hard to take him serious, and it's definitely not that easy to look at him as a threat, especially when our hero handles himself against him so effortlessly most of the time. Now, when there is action on display, it's pretty solid stuff.  The score is bombastic. It's heavy. It hits hard. The bass drops constantly to a laughable degree, though. Every time someone says a one-liner or even reveals some information, it's followed with a bass drop. And then... This loud music kicks in for like 10 seconds. Typically, it's the same theme song repeated at Nazium, and then we're back to talking or action again. Wash, rinse, repeat. I have to say, though, that Bollywood music hits hard as hell. Way louder, way stronger than anything I've seen from American films. We need to step up our game. And the director knows it, perhaps to a fault. There are at least four music montages in this, like little mini music videos that take place throughout. Now, this might be a staple for Bollywood films. I'm not that familiar with them, but it was like, I got it after the third. We didn't need to keep going and kind of rehashing everything that just played out. The movie does have some twists and turns to keep you engaged, but for the most part, it's a pretty straightforward affair. One that's not deep in the slightest, which is fine, but they really hammer you over the head with the messaging of social media and how they take advantage of these actors and how they spin stories. It's even met with multiple different news anchors who are constantly showing up, spouting a bunch of nonsense, and then we get the real side of the story, as we see Monov trying to escape. Trying to get his image restored back in shape and ready for prime time. I think what would have dramatically helped this film out is shaving down that runtime by like 20 minutes, maybe even 30. I've said this a million times now on the channel, but less is more. We don't need to push over two hours. I think this runs 209. Go back a little bit. There's lots of filler here that doesn't need to exist, and then we have a quick snappy movie that's in and out. You're left with the great impression of the fantastic action and music, and even a great performance by the leads, and then we get ready for a sequel. But as it stands, it's a fun film, nothing that would rush up to theaters to see, definitely something you could put on in Netflix and have a good time. Those are my thoughts on an action hero. Do you have any interest in going out and seeing this one in the theaters? Or you think maybe it'll come to Netflix or something, you'll just check it there. Let me know in the comments either way. Like the video if you had a good time. Please think about subscribing if you haven't. I post tons of movie content every week on the channel, and it's not just the mainstream blockbusters. Lately, I've been doing a lot of Patreon requests. I'm even doing Bollywood, Tollywood, a lot of Indian films that are coming out. I'm going to watch them and review them, so stick around for those as well. Take care. Wow, you might be thinking, this guy puts out a lot of good content, and he seems to like movies. Well, it's also not my full-time job, and I am a one-man operation. In fact, this is a passion project of mine that I would love if you could support me in. You can join me on Patreon at patreon.com slash adamdoesmovies. There's a $1 tier, a 10, a 30 even. At that level, you can request a movie, and I have to watch it and give you a shout-out. You can also become a YouTube join member right here by hitting that join button. I'm on Twitch, live streaming some of these reviews, and also doing a podcast with a buddy. So lots of ways to like and support the channel, and I would appreciate it.


All right, good morning, everybody. Welcome back. OK, so we're on lecture five out of six lectures for a quality module. And by and large, for every session, what I do is I let the students know what is it that is going to get covered. And so by the time they're done with this hour-long lecture, in this case, one and a half hour lectures, there's a sense of what will get accomplished. And then when you walk out from the lecture hall, you have a sense of accomplished something. You have a sense of having learned something. Some things might be new. Some things might be old and get reinforced. And some new questions might emerge. There's some work to be done, some reading material, some home assignments, et cetera. So the point is that by the end of the class, the students are walking out excited about new things that they have learned and that there's work to be done. So as I was saying, lecture five of air quality. And one of the things I always find a good idea, and it works very well, is to actually let the students know what would be the focus of today's lecture and that they can actually walk away from the lecture, having a sense of accomplishment and having a sense of new openings for action. So today's learning objective then is that one would be able to explain. I just say explain. It's when I say explain, I actually mean that you could explain to someone. You could explain to another student. You can explain to somebody in your family. You could explain to somebody on the street as to, what is air quality in terms of the particulate matter and how do you actually measure the size and concentration of particulate matter. We've discussed this over the last few lectures that we discussed concentration first. When we looked at sulphur dioxide and we looked at how much sulphur could be burnt in a room and we had said that the volume of the room is going to then determine how diluted that sulphur dioxide will get and whether that will be acceptable for breathing or not based on the three hour standard. Then in the last lecture, I think we focused a lot on the particulate matter, not the gaseous pollutants, but particulate matter and we said not all particles are created equal and therefore it's important to get a sense of the size because different sizes will either first be inhalable or not inhalable and second that they would have different chemistry and they would, because just by virtue of the fact that they come from different sources so some of them could come from just dust which is crustal in nature, geological in nature, benign, doesn't have a health effect whereas particles which are coming from chemical reactions or combustion can actually have a larger toxicity. So these particular size particles and where they deposit in the lungs is also going to determine the extent of the problem and it had turned out that the size of the particle, there's a certain range of size of particles which are both toxic and have a high chance of deposition in the alveoli. So therefore it's important to be able to deal with the size and the concentration. When we talked about size again, last time we had said PM10, we said 10 micrometers and above usually would get stopped by a normal adult human nose under normal breathing conditions whereas for anything less than 10 micrometers, it is considered respirable. So you will be able to breathe it in. Now most of it you will breathe it out also. It's just that there's a certain range of particle sizes which there's a good 70 to 80% chance that it will actually deposit in the alveoli which is the worst place because that's where all the blood exchange is happening and if there is some toxic effects then that's a direct contact in some sense. Okay, so let's continue with this then. We had talked about if students were to just ask to do a measure of the total. And I've just added this word since the last slide, last time I showed you the slide. Total, it's important to say total because we are not differentiating based on size. We're saying anything that enters this tube and that will get stopped by this filter is what we are measuring. So we're not distinguishing between PM10, PM2.5 or any other sizes, it's a total mass. And this is pretty straightforward and we discussed this last time as well. We also discussed the possibility of maybe giving some of these to your students and ask them to make their own estimates of what the pollution levels are. This is simple, you just need a filter paper which is pre-wade and then filter cartridge a flow meter like a rotometer and a vacuum pump and something to stop watch to be able to do the timing. And then you just need to do the mass of the filter before, mass of the filter after that gives you delta M which is the increase in the mass. Of course it's desiccated to eliminate the aspects of humidity. And then Q you have measured using the rotometer. One of the things I really emphasize a lot is whether the flow meter is calibrated. Most of the times the flow meters that are available they have a certain calibration but I just feel much more comfortable if I have calibrated it myself. And it is a routine practice in our lab that before any student starts any studies of any kind the instruments have to be calibrated and there needs to be a degree of confidence that if I'm saying 10 liters per minute I actually mean 10 liters per minute no more, no less. Very critical for all the measurements because a 10% or a 20% error in the flow meter over here would cause a huge change in the concentration which is not such a good idea. Especially if you're looking at meeting standards especially if you're looking at health effect of people. So it's important to kind of deal with it as a almost I would go to the extent of saying like a medical instrument. It doesn't have the importance is no less than that of a medical instrument. And that's the relationship I usually want to establish with students to say look when you are dealing with these it's like a doctor dealing with whether it's a thermometer whether it's a blood pressure equipment or any other analytics that go on for diagnostics. So it's important. So this is just a repetition of what we had done last time. I just wanted to let you know that this particular apparatus, this particular setup will only be able to give you the total mass concentrations which is good in and of itself. Just to caution again larger particles will tend to dominate the mass. So if you do this measurement somewhere in a village in let's say a desert area then the mass that you may get may be very large. Why? Because the particles are large course particles coming from dust coming from sand in the desert. So they tend to dominate. Whereas if you do a similar measurement at let's say a traffic junction in an urban area then the particles there's no dust, there is dust but assuming that the roads are clean, et cetera. Let's say that the contribution is coming only from vehicle emissions. Now vehicle emissions are small. It's almost like two orders of magnitude smaller than sand particles. So the contribution that they would have would be then 10 to the power of three times which means if it's 100 times lesser then you're talking about a million times less mass. One of the issues also comes up is whether the weighing machine that you have. Last time we had talked about doing this flow 10 liters per minute for 10 minutes. 10 liters per minute for 10 minutes. 10 liters per minute for 10 minutes which means total in the denominator would be 100 liters. But sometimes if the concentration is high then you'll get sufficient mass to be able to do this calculation. But if the particulate matter is small and the contribution to mass is less then that 100 liter may not be adequate for you to be able to get a detectable amount of mass. So therefore you may have to either run at a high Q value or for a longer time. Okay, again I spend a lot of time with students emphasizing the choice of Q and T. If you take high Q then you are taking the, you're getting a snapshot of what's happening immediately because the time is short. So in short time if you take high flow rate then you'll be able to get closer to the real time, closer to now what's happening. Whereas if you kept Q low, if you kept Q low and you extended T instead of 10 minutes you extended it to let's say three hours then what you will get on this filter is an average concentration over a period of those three hours. So there is enough, it looks very simplistic over here but there's enough science in this very small delta M by QT expression. One more time, delta M. There are many instruments that are available that are at a 10 microgram level of resolution but then sometimes for the work we do we require something which has a resolution of one microgram. Now the cost difference is huge between the 10 microgram instrument and the one microgram instrument. So I think a 10 microgram probably you get it for about one and a half, two lakhs. Whereas if you're looking at a one micro meter you easily shoot up to eight to 10 lakhs. So that's the kind of cost difference. Therefore the decision of whether you're going to use a larger Q or a larger T, that whole aspect comes in but one of these has to be larger for the mass to be collected. Okay so one last thing probably I keep thinking whatever I'm saying last is the last thing but then one more thought emerges and I think it's important to share this also. I use this entire lecture also to tell the students what does resolution mean, resolution of mass? And the example I give them is I say if you go to a vegetable store and you want to buy let's say potatoes, okay? The cost of potatoes is some X rupees per kg. Based on that what is the minimum resolution that the weighing balance should have? So assuming that nowadays the minimum exchange and currency is about one rupee, they would have to work backwards to see given a cost of potatoes, what should be the resolution of the weighing scale that they have? These days they have these single pan weighing balances. So they just put a basket on it with all the vegetables and then they just weigh that and then they even have a calculator over there that they figure out. But the important thing is what present? Are you going to buy it to the nearest gram? Are you going to buy it to the nearest 10 grams? Are you going to buy it to the nearest 100 grams? So that is going to determine is it the first place of decimal of a kg, second place of a decimal of a kg or third place of a decimal kg which is going to decide the choice of your scale. Then I go ahead and change the game a little bit and I say what if you went to a gold shop? If you go to a gold shop, the price per gram of gold is nowhere close to what we buy in a vegetable grocery shop. So certainly the order of cost of the material that you're buying shoots up by three orders of magnitude in which case then you have to do a calculation again that if you go to a jeweler shop, they don't deal with one rupee anymore. They probably deal with 10 rupees sometimes 50 rupees depending on if you're buying something worth thousands of rupees, they'd even round it off to the nearest 100 rupee. But if you're buying something which is about 700, 800 rupees then they'll probably round it off to 10 rupees. So I use this as an exercise to deal with the whole aspect of resolution. I'm not saying that people, students have not dealt with this in somewhere or the other like for example in physics or in chemistry or some other place they would have definitely dealt or even lengths and millimeters and micrometers and use of vernier calipers and micrometer screw gauges. They've dealt with it in some way or form. But a lot of times when I was studying, it remained an exercise to be carried out in a laboratory setting. I never really expanded it or extended it to my day-to-day usage for grocery shopping or sometimes when I go with my wife for jewelry shopping, I didn't go jewelry shopping till I got married. So after I got married, I started going jewelry shopping. So jewelry shopping, the whole idea of jewelry shopping, I excite the students even to consider going to a jewelry shop before getting married so they could actually go and talk to the jeweler and find out why did they choose a particular balance and if they go to the nearest one milligram or go to the 10 micrograms and what made that choice and how much does a weighing balance cost. And then I asked them to go to the grocery store and also check with the grocery stores as to how much does their single balance cost. So I do want students to begin to engage themselves in these measures because it's got to be like a, it's got to be like a sense that they have, like they would have a sense of how cold is water and what else, how cold is water and how much does one kilogram weigh. So if I pick up this bottle, I have a sense that it is about 200 milliliters. So it's about 200 grams. So I have a sense of how much it weighs. The first time I got into a shock was when I tried to pick up a bottle of mercury, the same volume of mercury, if you try and lift it, it'll be difficult to lift it. You'll be able to lift it, but it'll be difficult to lift. So 200 grams multiplied by a factor of let's say 14 for 13.6 specific gravity, that kind of shoots up to now kilograms, it may not be easy to pick up. That's one thing I say. Then the other thing I usually say is if they say this is a certain flow rate, let's say five liters per minute or a certain wind velocity, let's say two meters per second. It comes to, let's say the fan in the room. I actually asked them to know whether they know what that speed is. If I turn on the fan, will they be able to tell me what is the speed at this point? A lot of times people don't, it's difficult for students to be able to do that. So then I say, okay, now imagine if you were on a two wheeler on a scooter or if you were in a car and the wind was blowing in your face or if you were in a car and you put your hand out just for a little bit to see what the speed of the wind is, you get a sense of what is it that, what's that spin? So you see the speedometer, you say it's moving at 40 kilometers per hour, you stick your hand out, you have a sense of it.  So these are some of the things. It looks quite simple, but I spend a lot of time on this. And as I said previously, I thought this was the last thing I was going to say, but here's another thing to say. Another thing to say is the vacuum pump. A lot of times people, students have not dealt with a vacuum pump, so it's important for them to get to know if they were to buy a vacuum pump, what are the kinds of characteristics that they would have to look for a vacuum pump. So the entire design of vacuum pump and which pump they would choose is also becomes then a part of the exercise that they do in the class. So that's as much I want to say about some of these components. Again, flow meters need to be calibrated. You have to have a balance, which is sensitive, which minimum resolution is to the demand of what a delta mask can be. And of course you have a regular stopwatch. Okay, so that's that. And move on to the next slide. So we really therefore are going to be looking at sizing of particles. We're going to be looking at sizing of particles. And I'd said not all particles are created equal and we even talked about ants and elephants. So ants is not what we're dealing with right now. We're dealing with elephants, baby elephants, dinosaurs. So we're dealing with these. We're not dealing with these. These I'll describe later that all gases are created equal. Ideal gas law applies to all the gases, but that's not the same when it comes to elephants. Particular matter don't follow. In fact, the known laws of physics, for very small molecule, for molecular size, and the known for particle size, which are in the Newtonian regime, larger particles. Newtonian was known. So somewhere in between, the small particles and the large particles is the physics that only recently because of development of instrumentation. So that's why we are focusing so much on it because a lot of this stuff you will not even find in textbooks. The normal textbooks that you would have for environmental studies will not cover most of these things. So we'll keep adding these as resources as we go along. Okay, so we got ants and elephants and we're dealing with elephants and we want to be able to size these baby elephants, elephants, dinosaurs, et cetera. So this is the graph that I shared with you last time. We said why we are interested in different sizes is because if you were to look at ambient measurements, there's course mode, there's accumulation mode and there's nucleation mode. And we said particles less than 10 micrometers are respirable, anything less than 2.5 as more of a contribution coming from anthropogenic sources. So therefore, it's important for us, it's of interest to us to be able to get size distributions. So this is my association of sizing. You take flour in a kitchen, you take wheat flour or you take rice flour in a kitchen and you basically do the searing. So the first time, I need to share something with you. When I was a kid, I used to think that maida, flour, maida, aata and suji or rava. I don't know, I'm sorry, I don't know the English words for these three, but rava, aata and maida. I used to think that they come from three different grains. So when you have a naan, it is made out of maida. You have roti that's made out of aata and then when you have some halwa, shira, that is made out of suji or rava and I used to think they come from three different grains. And one time my mother wanted to make baturas at home and there was no maida at home. So she took some of the regular aata, regular wheat flour and she put it in one of her chunnis, the head gear that my mother used to wear. She took a clean one. So she took that and she put this over there and she did chik-chik-chik-chik-chik a few times and what came out of it was maida and I at that point in time, not that I didn't know it already, but for that time onwards it was confirmed for me that my mother was a magic woman that she would actually make aata out of, maida out of aata, okay? So that is my association with sizing, sizing of particles. That is my association with sizing. So if you look at this, civil engineers, chemical engineers, mechanical engineers, a lot of people in the area, in the business of materials, when they're looking at sand, everybody's seen when any construction is going on that there'll always be a little sieve which is put at a, you know, with a stand like this and they will take the sand and then with a spade they will put it over there and some of the large, smaller particles will go through but some of the larger pebbles will stay out. Seving is done, it's always done. So this is typically, you know, sieves that are used for analysis of soil for example. They also have these shakers. So this is a typical sieve shaker that you stack these up and you put the soil on top and then you basically close the whole thing and you shake it up for a certain amount of time. And what that shaking will do is that it'll actually help that if a particle, the smallest size, the smallest dimension of that particular particle when it comes in a certain orientation, it'll basically go through the hole. So the smallest size will go through the hole in the sieve and so you do that for a certain amount of time and then ultimately what is left on each of these sieve trays is what couldn't go through and then therefore you have a size distribution. This is a very clear understanding that everybody has. So why am I spending so much time on it? Why I'm spending so much time on it is that this intuition that we have about sizing does not work for particles which are respirable. These are not, this particular application is not. See, can you just imagine now to pick up particles which would be all less than 10 micrometers. I mean how would you pick up particles less than 10 micrometers input? Oh, okay, suppose you say you took talcum powder. You took talcum powder and you put it on a sieve. So first of all you'll have to deal with having whole size which is 10 micrometer. Whole size which is 10 micrometer which you cannot see with your naked eye.  You'll be able to see it if you take the sieve and you put it against the light then you'll be able to see a hole through it. Otherwise you may not be able to see it. That's for 10 micrometer and we're talking about particles which are of the order of about 0.01 micrometer and less. So just any chance that you'll be able to get a sieve of that size is gonna be difficult. So you cannot deal with it as a sieve. Second thing is when you put the stack, when you put the stack over here, you're dealing with the particles settling by gravity. You're banking on gravity to separate these particles. But when it comes down to 10 micrometer particle, one micrometer particle, 0.1 micrometer particle, those particles are so small that if you shake them up they'll probably get entrained in the air and not settled down because they're small enough. They're large enough as elephants and large enough as dinosaurs, but they're small enough that all the ants around them will tend to keep them suspended. So they have a very low, very small settling rate so the chances of you to be able to actually separate them based on sieving is just next to impossible. So therefore we're in trouble. We're in trouble because we actually have been thinking of separation of size based on our understanding, our learnings have been that of sieving and suddenly I'm now left with, I don't know how to separate out these particles. I don't know how to size these particles. So I don't want to be alone in this dilemma, so I'd like to share that dilemma with you and have you do a little bit of work on it. So here's a class assignment now that I give to the class. So let me go ahead and flash the class exercise. There we go. The thought exercise, the thought exercise is how would you size and count? Size and count aerosol particles in the nanometer size range. These are particles which begin to be less than one micrometer. So particles which are less than one micrometer. How would you size them and count them? So I'm gonna connect with, so this is... Is Kaylee, we are back again. Kaylee, we are back again. All right, I like the way you guys respond. Very good. Okay, so somebody please take the microphone and tell me what ideas that might be there to size and count particles in the nanometer size range? Sir, it will be measured in micrograms per meter cube. But how would you do that? Particulate matter. High volume sampler for PM10. Excellent. And if it is 2.5, it is RSPM, Respirable Suspended Particulate Micro Sampler. Excellent. All right, very good. Very good. Excellent, excellent. Very good. Who else? Okay, GRI, ET, Kokatpalli, Hyderabad. How are you? Hyderabad. Good morning, sir. All right, excellent. So one of you please tell me, how would you deal with? How would you deal with sizing and counting particles in the nanometer size range? Hello, sir. Good morning, sir. Good morning. Sir, by using any instrument like particle size, we can determine, sir. Like microorganisms, we are using colony counters for counting the number of microorganisms and all. So by using particle sizes or spectrophotometers, we can determine these aerosols, sir. Excellent, excellent. All right, so very good. Thank you, thank you very much. Thank you very much. Next please. Okay, actually you can see very good. Hello everybody. Hi, very nice, okay. So one of you please share. Hello. Yeah, please. Sir, shall we use some fluorescence particle size measurement analyzer or some Temman also transmission electron microscope? Yeah, very good. So I think the thinking is all in the right direction. All right, so I'm gonna move on now. Just give you an example. I'd gone to meet with Professor Peter McMurray one time, okay, at the University of Minnesota. And one of the things I learned from him was that when we get an instrument in that lab, Professor Peter McMurray, he's one of the founding fathers of aerosol research at the University of Minnesota Department of Mechanical Engineering, Peter McMurray. So when Professor McMurray said, you know, when they get a new instrument in the lab, by the way, a lot of instruments get developed in that lab, okay, but if they get a new instrument from outside, the first thing that they do is they take the cover, they take out the cover, the top cover, they take the top cover and they throw it away and they take the manual and they have a ritual in all and all the students and all the other faculty get together and they have a ritual that they burn up the manual, okay? So I was a little, I looked at him like, you know, a little strangely, he says, no, we do that because we don't want the manufacturer of the instrument to tell us what we can or what we cannot do with this instrument. So I was quite excited by that idea to be able to open up the instrument and tinker around with it. And then some years later, I came back to India and the relationship that we have with instrument is very different, okay? We are very scared to open up an instrument. We don't want to touch it or spoil it. And it's, I think it's fair because a lot of money has gone into buying an instrument and you don't want to mess with it. But I'd, you know, I usually like to evoke this interest among students and I, anytime an instrument goes bad, I don't throw it. So there's no write-off of instruments as far as I'm concerned. Any instrument that has gone bad becomes now a resource for me for education. So I actually will use it in the lab, ask them to open it, ask them to remove it, ask them to break it if required and do all kinds of crazy things so that actually I have an appreciation of what is instrumentation, okay? So the relationship shifting between it being something that is something to be scared of, you know, I push in the sample and I push a button and I get some results out and then whatever those results are now, like are, you know, the universal truth. No, that's not the case, okay? You gotta have a healthy relationship with the instrument. I mean, you gotta know when it's working, you gotta know when it's not working. And the only way that you only will be able to do that if one understands the inside out of that instrument. So I'm gonna share with you some of the principles of these instruments that are used so that instead of it just being a name, it actually becomes something that you can design yourself, okay? So let me just go ahead and show you the next few slides. So what we're gonna be dealing with is inertial impactors, okay? Inertial impactors is what's at the heart of that principle of principle of inertial impactor is what you have is elephants that are suspended in ants, okay? So if the order of magnitude is three, okay, then the mass is going to be 10 to the power of nine, cubic relationship, okay? So you've got ants and you've got these elephants which are 10 to the power of nine times heavier than the ants, okay? So we understand inertia quite well. So if you were to take a gas stream and pass it through a jet like this, which has particles over here, and then you insert some kind of an impaction plate or some kind of an obstruction, this q over here, the flow over here, splits up to go in either direction because ants get a sense that there is obstruction so they still have to keep moving because they're at a certain velocity. So the ants are coming in, they go through this nozzle, suddenly there's an obstacle here so they start taking a turn, okay? All the ants start taking a turn, all the ants start taking a turn. However, some of the elephants, which are being pushed by the ants, okay? They try and take the same turn but they're too heavy to be able to take that turn because of their inertia, okay? So they therefore impact out. So a large particle moving at a high velocity through a nozzle when it experiences an obstacle it cannot take that bend that the fluid is taking and therefore will impact out, okay? So this is basically the impaction plate or the collection plate, this here is a nozzle, this is the gas flow rate, this is an elephant which basically couldn't make that turn along with all the ants. That's the principle, it's called inertial impaction, okay? I got this image from this URL so you're welcome to go there. Now instead of having one impaction stage like this, in an instrument, in a cascade impactor, you have a cascade of these stages and why you have cascade of these stages is because you want to change the size of the elephant that you're going to capture, okay? So let's take a look at this for example. So this is the first impaction plate, this is the second impaction plate, this is the third impaction plate. There can be as many as 10 impaction plates in an instrument, okay? Up to 10 stages. So when you look at this now, you look at particles that are all sizes.  So you got three sizes of elephants and of course ants you cannot see, okay? The gas stream that is coming through is ants, ants, ants, ants, ants, ants, right? Millions and millions of ants, billions and millions of ants and in there somewhere are also suspended some of these small baby elephants, medium-sized elephants, large elephants, okay? These are all coming along with the flow. These ants take a turn over here, ants take a turn over here. The small baby elephant and the medium-sized elephant are also small enough that in that small time that is available to them and start pushing them, so they also take that turn. However, the largest elephant, too bad tragedy, it couldn't take the turn, okay? So it impacted out on the surface. Oh, okay, so what do we do?  Metal foil, I put a piece of aluminum here which has been pre-wade, okay? It has been wade before and I run this instrument and this instrument is flowing at a rate of, let's say 30 liters per minute, I'm sampling 30 liters per minute and I run it for let's say 30 minutes.  So then after running it for 30 minutes, you take this foil and you wait again. The difference in the mass will give you the size of the particles or size of the elephants of a certain size, bigger than that certain size, okay? So that's the first stage, that's what you've done. Now, you go to the next stage but this time what you do is, you decrease the size of this nozzle. Notice this nozzle here, this opening over here is smaller than this opening, okay? The flow that is going is the same. So 30 liters per minute going through this nozzle. The same 30 liters per minute is going through this nozzle but because the nozzle's size is smaller, the velocity is much higher compared to this stage. So if the velocity is higher, the small elephant and the medium elephant which could not impact over here now will experience enough inertia that the medium size elephant will impact out but the smallest size elephant still escapes it. So now what you have is, you have large elephants which have deposited here, medium size that have deposited here. Now you take it to the next stage in which the diameter of the nozzle is even smaller. So now you'll collect the smallest size over here and then at the end of the whole cascade impactor, the whole set of 10 stage impaction stages, collection stages, you are left with a filter paper which removes the rest. And of course there's a vacuum pump over here which is sucking at the rate of 30 liters per minute. So then what happens is you take this filter paper or this metal foil, you take this metal foil, you take this metal foil. You have collected particles, you have collected elephants of different sizes. The largest one over here, the smallest one over here. So if you take the mass of particles collected on each of these stages and you plot them on the x-axis, you have the size of the particle and on the y-axis you have mass collected, you actually get a histogram. That histogram is a size distribution. It's really very simple. All you need to pay attention to is that the nozzle size over here, the nozzle size keeps decreasing as a result of which the particle which could not impact over here as it gets to higher and higher velocities, it has more and more inertia and therefore cannot take that 90 degree turn and therefore impacts out. So that's the principle. It's called a cascade impactor. Each of these stages is called an impaction stage. And these are quite popular when you want to get size distributions. Now I'll just give you some, show you some examples, okay? Oh, by the way, you know just in a previous lecture I had shown you the measurements that we had done at Parel and at Worley, you know, by Nitin Goyal. Those were actually taken by this instrument. So you actually did the size distributions of the atmospheric aerosols at these two locations at different times of the day, okay? Okay, the following slides are a PhD work of another student of mine. His name is Selva Kumar. So this is something which we did. Remember I said to you in the beginning of the lecture that I'm a stickler for calibration, okay? I'm a stickler for, you know, making sure that if I'm saying that it is five liters per minute, that it is five liters per minute. When I'm saying that it is three micrometers, that means it is three micrometers, okay? So you can check it under the microscope. You can take it to an optical micro, three micrometers is usually measurable under an optical microscope. But if it is smaller than one micrometer, then you might need to take it to a scanning electron microscope where you can do the sizing, okay? But you have to do some of those things to be able to make sure. But, you know, if you didn't want to go outside, and you just wanted to use whatever you have in the lab, for example, if you had a cascade impactor, and you want to know whether the cascade impactor is working properly or not, okay? So what we did was something interesting. What we said was, and this is not something new. It's done quite routinely. So what we did is we actually said, let's take a salt solution. Instead of clean water, we take salt solution. We take a little bit of water, and you mix a known amount of salt in it. And we then mix it up, make it into a solution, and then spray it. So spray meaning, like for example, you know, anytime you use begon spray, right? You go, it basically has a spray coming out.  So the spray, you can actually see the droplets, okay? Those are the droplets. Now instead of water, if you put the salt solution, these water droplets, when they dried up, would turn into salt particles, okay? The salt solution, when it dries up, will become salt particles, okay? So in one case, we took five grams per liter of the salt. In another case, we took 40 grams per liter, which means eight times, okay? Five grams per liter, and then we took 40 grams per liter. That means we took a mass, which is eight times more. So then we expected that the particle size would double by, would double, would increase in size by double, factor of two. Why? Because the volume of the mass is dp cubed. So if I have the size multiplied by eight, the mass concentration multiplied by eight, instead of five grams per liter, if I took 40 grams per liter, I've increased the mass or increased the volume by eight times. So which means that the size of the diameter of the particle should double, okay? So that's a trick that we used, and we actually worked out pretty well, that for, let's say for five grams per liter, we got a size of about 0.6 micrometer, whereas for 40, we got a size of about 1.01. Not quite double, but all the same. And then we did another shot, where we multiplied it by a factor of eight again. But not 320, we took 300, because it reaches a point of saturation. The solubility limit comes in, so we kept it at 300, and it went from one to 1.9, almost doubling. So those are some of the things, which in a few doing research, it's important to check that. But I also see that as a way of evoking a sense of rigor, a sense of being particular about measurements among students, okay? So this is one of the exercises that we had done. I also talked a little bit about the chemistry of the particles. And so the particles that we collected at each of these stages, we actually did some chemistry on it, okay? So this is, we did some edacs analysis. And over here, what you see is different stages of that cascade impactor, okay? The biggest size were on stage zero, and the smallest size were on stage 10. The biggest size was 18 micrometers and above, and the smallest size was 56 nanometers, okay? So there's a whole range of particles here. And what you see over here is the chemistry. It's a 3D plot. Here you have the size. So the largest size is furthest away from you, and the smallest size is closest to you. This here is the chemistry. It is actually different elements that were detected using edacs. And it turns out that the largest particles, this is by the way from a wood gasifier. So we were interested in deposition of particles coming from a gasifier for many reasons. We won't get into the reasons, but our interest was to characterize these particles. So when you looked at the larger particles, they tend to be more of SiO2, ash particles, okay? So the chemistry was showing that large particles. By the time you got to the smaller particles, there was hardly any SiO2. So most of the SiO2 was therefore in the larger particles. But as you got to other elements, and you got to carbon, for example, some of the larger particles had no carbon at all, whereas the smaller particles were almost 100% carbon, okay? So this is something we talked about yesterday that depending on the source, depending on the source of particles, if it is coming from ash, then the chemistry would be very different. If it is coming from combustion, and it is carbonaceous, the chemistry would be very different. So this is another way that you could use a cascade impactor. You take the sample from each of those stages, which you know are different sizes, and you take and do the chemistry on this to be able to see the chemical composition. Okay, this is what particles look like. So there are many, many images available for particles from different sources or different sizes. A lot of times people use morphology of the particles to be able to identify them. Okay, particles are seldom spherical. Most of the particles in the atmosphere are not spherical. It's very rare that you'd have spherical particles unless they're droplets. If they're liquid droplets, then they tend to be spherical. But otherwise any crustal material, any suit particles, they tend to be irregular shapes, and they sometimes get to be like agglomerates and chains. So when we're talking about diameter of a particle, it's a difficult question to say, what would you call the diameter? So invariably when we're talking about diameter, we actually have a definition called the aerodynamic diameter. Okay, and what aerodynamic diameter means is that if I had a spherical particle of unit density, spherical particle of unit density, and I have this arbitrary particle with unknown density, some diameter, I don't know, but if these two are settling at the same rate, then the aerodynamic diameter of this particle, unknown size, unknown density, the aerodynamic diameter of this would be the diameter of this particular spherical particle of unit density. Okay, so that's aerodynamic diameter. Again, I'm not gonna spend too much time on it. I usually give this as a class assignment and also as homework, okay? Okay, the next few slides are from the work of Dr. Nitin Goyal. He did his PhD some years ago with me. Okay, so what I showed you was a 10 state cascade impactor, okay? At that point in time when he had bought it, it cost some eight lakhs. Some part of it came from some project money, part of it came from the departmental funds, okay? I don't know what the present cost is, but at that point we bought it for eight lakhs. Now, eight lakhs is quite expensive. I mean, if you wanted to buy an instrument and use it routinely for students, it's difficult, okay? It's very difficult to kind of have that kind of money be available. And one point in time at the most two or three students work and if you have a class of 25, 30 people or more, then it's really, you know, difficult to be able to distribute that same instrument to everybody. So what we said was, we said, okay, can we do some cheaper alternative? We want to make something indigenously. So as a part of the work that Nitin did, he actually developed the single stage impactor. So it only measures PM 2.5. So any particles that are greater than PM 2.5, they get impacted out. And anything which is smaller than PM 2.5 gets collected on a filter paper. So our interest was in PM 2.5. The same instrument you could also use for PM 1. We recently tested it for PM 1. All you had to do was, instead of operating at six liters per minute, you operate it at a different flow rate at a slightly higher flow rate. So particles larger than one micrometer instead of larger than 2.5 micrometer can impact out. Okay, so that's a play that you could do. You could even have students, you know, design one of these, fabricate one of these. This cost some 6,000 rupees, okay? It was made in a local workshop close to IIT campus, a place called Bikroli, which is close by, okay? So this is just what it looks like. It's made out of aluminum, simple connectors over here. Once you assemble it, these are the nuts and bolts you can have. These are the impaction stages, okay? These are the impaction stages. This is where the particles would deposit out. And then at the end, you would have a filter paper on all particles, for all particles that are smaller than 2.5 would get collected and that's what you could do chemical analysis or you could do the weighing, okay? All right. Okay, now, when we designed this, we called it the SSI, the single stage impactor. 6,000 rupees compared to 8 lakhs, okay? We just wanted to make sure that we were doing the right thing. I mean, does this, you know, indigenous instrument that we have made, does it actually compare well with the commercially used, well documented, well established 10 stage impactor, which is called Moody, the micro orifice uniform deposition impactor, okay? So we compared and they compared pretty well, okay? So our design was okay and we could then actually use a single stage impactor for class studies, lab studies and also for other research work. Okay, so that was inertial impaction. We can go all the way greater than anything, greater than 56 nanometers can be impacted out. Anything smaller than 56 nanometers, it now gets small enough that you can't differentiate between ants and elephants in terms of inertia, okay? So anything larger than 56 nanometers has, is available, is commercially being used. I think I believe there is another cascade impactor which has come which goes even smaller than 56 nanometers, but I haven't actually had a chance to check it out, okay? So inertial impactors, everybody, very simple, very routinely used. So two of you, you know, mentioned some of the instruments when you said that you use a PM 2.5 sampler or when you use a mini wall sampler, not a high volume sampler. In a high volume sampler, you don't use this principle of impaction. What you use is cyclone. So I'll talk about the cyclone in the next lecture, but what you do is, again, there, also you use the inertia of the particle to separate it out from the gas stream and all particles which are greater than 10 micrometers would get removed and you get particles, you get gas which is now removed of 10 micrometer particles. So everything that is left over there and then these PM 10, which is what is used in high volume samplers, okay? But in anything which is other than high volume sampler, mini wall samplers, you know, other samplers that are using, which are not optical in nature, which are actually mass based, by and large they're using this principle, okay? So that's the inside story of what's going on. And I just want you to know, I'll send you a paper, by the way, our entire intent in developing this particular device was that it is in the public domain, okay? We actually have all the drawings that are available. We tell you how to test it. We tell you how to get it fabricated. All those details are available. And so I'll even put it up as a challenge to you. Go ahead and for the next lab class that you have, you just give it to students, you probably need to give them a little bit of money, not more than total budget of about 10,000, which therefore they can go ahead and fabricate it and test it out. You will need a vacuum pump with this and of course the filter paper or the cascade impactor, the foil, you will need a weighing balance. So those are things that you will need. But all the other details are available in a paper in Current Science, I'll send you the link for it, in Current Science by Nitin Goyal and co-workers, so you can go look for it. I think it's somewhere 2008 or so, I'm not too sure, but somewhere about seven, eight years ago. Okay, so that's that. And so this part over here, which is again hidden, is actually now optical particle counting, okay? Optical, you use optical. So the principle is same as why is a cloud visible? Okay, it's visible because it scatters light. Why can you say between one glass of water, which is clear and one glass of water, which is turbid, so turbidity? Why would a certain sample of water or river water or even drinking water sometimes, why is it turbid? Why is that turbidity? Is because it has some suspended particles in it, which are scattering light. So if it is scattering light, that means it is an elephant. Now, sorry, I don't mean to say it in a way that ants don't scatter light. Ants are also scattering light. Ants are scattering light in the form of a blue sky. Okay, molecules, gas molecules are scattering the light, therefore you see a blue sky. But when you see white smoke, sorry, or white cloud or even white smoke, or you see black smoke, that is more because the elephants are now scattering light or in the case of black smoke, they're actually absorbing light. They're black, they absorb all light, so therefore you can't see it.  You see it because you don't see it.  So just to emphasize that in one case, you're scattering light. In the other case, light is being actually absorbed, okay? So the difference between black particle and a white scattering droplet is that white scattering droplet scatters all the light. It doesn't absorb any light, whereas a black particle absorbs light. So that's the basic principle. And what you would do is then you would actually say there are two parts to it, like scattering is no absorption, extinction is when there's absorption. The limit to measurement using an optical method, not microscope, even with the optical microscope, this is the limitation. The limitation is the same. You've got wavelength of light, which is in the 0.4 to 0.7 micrometer range. So you cannot distinguish anything smaller than that. The size of the probe is going to determine the characterization that you can do with it. So typically the size that we deal with is limited to about 0.1 micrometers when it comes down to optical sizes. You can use a single particle detection, which means one particle has to pass through the laser beam at one time, or you can take a cloud of particles. So for example, if you're looking at a turbidity or if you're looking at cloud, scattering from cloud, then that is a collection of particles. Turbidity is a collection of particles. So you can do single particle or you can do a cloud of particles. The principle is simple. You basically have a laser source of a certain wavelength, which is going through an optical cavity or optical space. And you have these particles of different shapes, different sizes, different refractive indices that are coming through. As soon as a particle passes through the laser beam, it will scatter light. And a good example of this is, I'm sure you've seen some of these laser shows, okay? They have these laser shows, rock shows, laser shows, sometimes on TV and some of these India's Got Talent or Nuchbelier or all of these different programs. They'll have a lot of laser beams going across and they also have smoke coming across. So they actually have to have the smoke because if they didn't have the smoke, the gas molecules will not scatter that light, okay? So the smoke is essential to be able to have a laser show. So that's basically the same principle over here. You have a laser beam coming through. Instead of a cloud of particles, you actually have a single particle going through it one at a time. So as this particle goes through, it scatters light. So as soon as a particle goes through, it scatters light. There is a detector here which actually sees, oops, there's a particle there, oops, there's a particle there, oops, there's a particle there.   So every beep is a signal. That means the particle is gone. Now, the size of the particle is going to decide what is the size of the beep, okay? What is the signal? What is the size of the scattered light is going to decide, is going to be decided by the size of the particle. So in some sense, there's a graph over here which shows that if this is the particle size, then then some linear relationship between the size of the particle and the scattered signal. This is the eye scatter. This is the eye incident over here. This is the eye scatter. So this is the intensity of the light, okay? So this is some kind of a linear relationship over a limited size range. So this is the linear part which you can use. So if you know the amount of light scattered, you can go from here and then interpret the size of the particle, okay? Again, unlike the previous time where we dealt with an aerodynamic diameter, we are now dealing with optical diameter. The optical diameter is not the same as aerodynamic diameter. If this instrument says one micrometer and if that instrument says one micrometer, if you put them both under the optical microscope, they will not measure same. Very rarely will they measure it to be the same size, okay? So different instruments will give you different nominal diameters. So in one case, it is aerosol optical diameter, sorry, aerodynamic diameter. In this case, it is optical. And in the next case, it will be electrical mobility particle diameter. We'll get to that. So this is what it looks like, size. So you have to make sure that these particles are coming one at a time. If they don't come one at a time, if they come two at a time, then the amount of light scattered will be higher and the instrument will not interpret it as two particles but as one large particle. So you have to make sure there is no coincidence of these particles. It's called a coincidence error. You have to keep these particles sufficiently far apart from each other. And how you keep them far apart from each other is that even if you take, for example, smoke, which has very high concentration of particles, you take smoke sample, you have to dilute it with clean filtered air so that these particles can be separated about far enough so that when they pass through the laser beam, they pass one at a time, okay? This is typically the cross section. Just this one was just a simple schematic which I had drawn. This is a schematic from a commercial particle counter. This is what it looks like. Same thing. You have some way to generate a laser beam. Particles are coming through a jet over here. They pass through the space. There's some filter, which is a monitor, which is, sorry, there is a sensor which is monitoring the power which is coming from the laser so that it compares this against what gets scattered, et cetera. So there are internal checks. They have to do quality assurance and make sure that the instrument works under various conditions even when the intensity of the incident beam itself is decreasing, it basically normalizes for the scattered signal here, et cetera, okay? All right. So that's as far as optical particles is concerned. Let's move on to the next slide. This part over here is now electrical mobility. What is electrical mobility? Again, I think everybody understands from class 11, 12 from the electrostatics that we had studied that if a particle has a charge and you put it in an electric field, that it actually moves, okay? There's electrical mobility of a charged particle. So we use that principle for these particles which are otherwise quite small. They cannot be sieved. They cannot be, you know, even the mass may be sometimes too small to be collected on a filter paper over a short time. So you want to use some way to be able to keep them in suspended still in the gas phase, use these electrical properties to be able to size them in real time, okay? So what you do is you basically charge these particles, atmospheric particles, you charge them and you put them in an electric field and that basically will then size them. So you can, I'll show you the, I'll tell you what I mean by sizing, okay? This is by the way the URL for the instrument which is being sold by TSI. You're welcome to go see it. So this is basically now fairly complicated but okay, I'd like to just focus on this part, okay? You charge these particles. These particles are coming. The atmospheric particles are coming which are already charged and then they enter this particular window, okay? They enter this window. They have a certain charge distribution to them. They're all sizes. Small size, medium size, large size, all size of particles are entering. Each one of them, depending on the size, would have picked on a certain charge. So the size mass charge distribution is established. It is well known. And now you have this particle which is introduced here and this is a central tube and this is an outer shell and in this annular space, there's an electrical field. So particle of a certain size with a certain charge will follow a certain trajectory. If the charge is higher, it'll probably move faster. If the charge is smaller, it'll probably go for a longer trajectory, okay? So this trajectory now is going to be determined by the size and charge on that size, okay? So for one particular electrical field, strength, you will get one trajectory or one particle size to go through this window. So you take this particular window, the particles coming from this window, you take that size over here and you put it through what's called a condensation particle counter. I'll talk about that. So what you really done is, you have taken all the sizes in here. Of those sizes, you have taken particle which follows one particular trajectory, particles which has followed one particular trajectory, which means it is one particular size and then you pass it through a counter where it gets counted. So what this piece of instrument has done is done the sizing. It has picked up one particular size and now in this particular instrument over here, it is counting the number of particles of that particular size, okay? So you did one size. Now you want to pick up particles which are of a larger size. So what you do is you decrease the electrical field a little bit. So the earlier particle which was impacting here, now because the electrical field is lesser, we'll follow this new trajectory for the larger particle and now this particle will go through this particular same window and again go to CPC. So what you do is you keep scanning the electrical field, okay? So you keep going up and down on the electrical field. You keep scanning it up and down. The computer algorithm keeps track of when the electrical field was a particular value and at that point in time what is the particular size that would have hit this particular special window which then got counted, okay? So very neat. It's really neat. In real time, in 20 seconds, you'll actually get the entire size distribution of particles. Okay? This is state of the art. I told you that the Moody sampler cost about 8 lakhs. The OPC particle counter depending on again which grade you get, it varies anywhere from 10 lakhs to 32 lakhs. This instrument over here, the combination of these two instruments over here is about 45 lakhs, okay? So that's the amount that you would have to pay if you wanted real time measurements of particulate matter still suspended in gas phase. You didn't collect them on any surface. They're still in gas phase, okay? In gas phase, you actually got the size distribution. It's very critical especially when you're dealing with synthesis of nanopowders and you want to see whether a particular process change has influenced the size. You don't want to collect it on a paper and do some electron microscopy. You want to do it in real time, okay? So this is an advantageous instrument over there. Okay? This over here is now the next part. So this particular instrument had two parts to it which is the sciser and this is the counter. So what do you do? How do you count these particles? They're in the nanometer size range. This instrument can go up to three nanometers. So now you've got three nanometer particle but how are you going to count it, okay? So then you use a trick. You pass these particles which are coming up to three nanometer size. You pass them through a chamber which is saturated with alcohol. Nowadays they also have it with water but the routine, the one that I have used used to have alcohol, okay? This is alcohol vapor. So you have this section, a tube, a flow in which particles of three nanometer size or five nanometer size or 10 nanometer size depending on which size is coming through at that time is going through this space and this cavity is completely saturated with alcohol vapor, okay? Now temperatures are lower now. So this particle which was three nanometers or five nanometers or 10 nanometers actually now begins to have condensation begin to take place on it and that condensation makes this particle which is very small in size grow to a certain size which is now detectable optically. So the same principle that we had used for optical particle counting can now be used but the optical particle counted counters were limited to 100 nanometers but if you have particles smaller than 100 nanometers then optically you can't detect it. So here's the trick you use. You actually use alcohol vapor condensation on each of these individual particles. You make them grow in size and then you detect them optically, okay? So that's the nature of the instrument and that's how it works. So I actually have half a minute left. I'm gonna just quickly flip through these. I have one more lecture with you, okay? I have one more lecture with you so I will review everything that we have done include complete some of this work over here. I've got about eight slides which I will take over in the next time, okay? But let me just flip through. This is some more details. I've already talked about this. This is some of the other instruments that are used. This just again gives you the cost. I'll upload this on Moodle just now after this lecture, okay? You're more than welcome to see it. Again, you know, when we are done with elephants and dinosaurs, what do we left with ants? We haven't dealt with gas analysis, okay? So for gas analysis, you basically, these are the gases criteria pollutants. You have primary gases and secondary gases and then you left with, I said this in the beginning of the lecture, not all particles are created equal. However, all gases are created equal but the chemistry is different so you can use the chemistry to be able to use different detection methods. These are the different methods by the U.S. Environmental Protection Agency, oxides of sulphur, oxides of nitrogen, carbon monoxide and ozone. These are the different methods which are used to detect. I'm giving you these two papers to read by June 12th. Okay, before June 12th, before the course ends, I'd like for you to read these two classic papers on, so maybe spend half an hour on each. If you started to read each one of them rigorously, it'll probably take you six, seven hours, okay? But just spend half an hour on each to get a sense of what these papers are before June 12th and then you can spend some more time on it. Okay, ladies and gentlemen, sorry I'm, you know, two minutes over time. I appreciate your time and your patience and your attention. Have a lovely cup of tea, coffee, whatever you're having and I'll see you back in about 28 minutes. Thank you, bye-bye.


The fact that the small town, the grassroots America, believe in local control. They believe in local determination as you do. They're symbolic of apple pie and motherhood. This pie also symbolizes that we, the nations, towns, and townships, look forward to our fair share of the federal pie. War II, one aspect of town government is that people know each other. Some are even related to the typical of the humor and the flavor of small town America. It's about a fellow named Elmer in his town. He, but he was able to provide so many fish every day that the game worked out a little suspicious.  I tossed him overboard and with the explosion up came the fish, belly up. The sheriff said, Elmer, did you realize you just committed a felony? Elmer, read them up. The sign suggests that we're over the hump, but as is engraved on our national archives building, eternal vigilance is the price of liberty. Good to see you again. And Governor Carl. Brendan, good to see you. Good to see you. Well, let's come in and sit down here. Thank you. Thank you. Hi, Jim. How are you? Good to see you, sir. Hi, Jim. Hi, Jim. Good to see you. Hi, Jim. Good to see you. Right, good to see you. Right, good to see you. How are you? Good, how are you doing? Good, great, while you're here. Here tonight as well next year is going to be great. You've got a year to go, right? That's right. Even in training we're not going to let him retire. We're going to have to do all the work. Just the way he's gotten life. Sure, not. We thought we'd come in and report to you today the summer meeting of the National Governors Association in Portland, and also to raise a couple of subjects of immediate concern to governors. There are some pressing national problems that most of us have. Nice to see you. Nice to see you. Nice to see you. Thank you. Pleasure to see you. In my three sons, Bruce, President Bruce, and Martin, and Van Juner. Hi, how are you? Well, yesterday my desk place was clean on the night. Well, very good. Because I'm not blocking you. And it's very useful. I like it. Wait a minute. I like joining my company. I like joining. Get your bar. All online. Thank you. Thank you. Thank you, sir. And thank you all for being here. Mr. President, they were just asking me, what are we doing to implement the recommendation of the National Commission on Excellence? I described the regional forums that were unfolding, and I'll just report to you we have five more of them to go, and then we're going to have a sort of a nationwide meeting the latter part of November. And so we're working with the governors, and we're determined as you told me to follow through on that report. And she's at the recommendation director. So that was a question, Justice UK. You got the answer. I'm sure that the Secretary has informed you that we're very interested in restoring excellence to education. It isn't excellent in this country, and he's told you the various ways that the Commission has recommended and how we are working toward that. We think, and not with the federal government abandoning any legitimate responsibility that it has, we do think that maybe some of the problems with education have been too much interference by the federal government where education properly belongs back at a level nearest the parents and in the community with regard to how it is managed, how it is run. And we, it hasn't been touched upon, feel very strongly about something that I know is of interest to you, which is bilingual education. I hope that we're not in disagreement. I happen to be in disagreement with a move that the federal government sort of drifted into with regard to that where it was not meeting the necessity of bringing children of whatever background into the ability to come out of school and deal with the world in the language that is our standard language here. There was less of bringing that about certainly in the federal government's approach and more of simply preserving the language that they did speak and that is going to send it out into the job market pretty soon. And it is very, very, very important. And that's something that I've been hearing for a while. I've been very, very pleased to talk to you all. And I appreciate your time. And I think it's going to be an issue of my heart because you've discussed it with me. And I think it's going to be an issue of your heart that's actually going to be a success. Well, that's going to be a mess of the phone. That's going to be a mess of the phone. You've then started to be able to pull out for a second session to be out of that period now. So I'm going to hire a third. Yes. And then you'll, um, I'll tell you today that I'm all of you. Thank you very much. Thank you very much. This is the rest of the world unless the facts stand out to be counted. And Russia must either accept the rest of the world's appraisal or they must identify themselves that's not willing to participate in safety matters and some radiation. And therefore we intend to take a very firm position and get to it. I don't know that, uh, there's anything more I can ask of you. I want to thank you for your outstanding support and those of you here and the people. Thank you very much.


Cool. Hi, everyone. Thank you so much for joining our webinar. My name is Tian Gan. I am a postdoc working at the CSDMS team. And this is Mark Paper. Do you want to introduce yourself? Sure. Hey, I'm Mark. I'm a research associate at CU, and I work as a research software engineer at CSDMS. Cool. Yeah. Today, Mark and I are going to talk about data components. And can you go to next slide, please? Yeah. In our presentation, we will first introduce about the CSDMS workbench and one of its major elements, which is basic model interface. BMI actually is the foundation of the data components. And then we will introduce some existing data components, which are created by our team. Followed by that, we will show the general steps to show you how to create your own data components. We also want to talk about the CSDMS and HydroShare capability. This capability will help you to share your tutorial different notebooks for your data components with the others, so they can easily run them and learn about how to use your data component.  And Mark is going to give a summary of today's webinar. So now let's get started. All right. Tien, you're very brave for doing a live demo, but it's going to be great. Thank you. All right. So before we get into the idea of data components, let's give some context. All right. So I want to start with the idea of the CSDMS workbench. So this is a set of tools and libraries that are produced by the CSDMS integration facility as well as with help from the CSDMS community as well. The idea is tools, libraries, software for building models, for running models, for coupling models. So three elements of the workbench are listed along the bottom here. So land lab is a model coupling toolkit. It's also a toolkit that you can use for building models in Python. It's really cool. It's the most popular element of the CSDMS workbench. On the other side is PMT. This is also a model coupling toolkit. And it's a little different in that it's used more for working with models written in other languages. So through PMT, you can couple models written in C, C++, and Fortran as well as Python because PMT is a Python package. So just as an aside, we're actually looking at incorporating PMT into land lab so we would have just land lab. Land lab would be our model coupling toolkit. But that's a little bit in the future and not quite the topic here. But I'm excited because I think it's a neat idea. All right. So anyway, there's two coupling toolkits are listed. In the middle is BMI, the basic model interface. And this is the technology that underpins both of these toolkits. So what is BMI? BMI is the basic model interface. So all that a basic model interface is a set of functions. These functions are a little special in that they have prescribed names and arguments and return types. But the neat thing is that these functions have the same names and arguments and return types across languages. So the idea is that you could write a model and it could have its own interface, whatever interface you design for accessing information in the model for running the model. But you could also put a BMI on it and then you'd have a standardized interface for accessing and running your model. So that's kind of what a BMI is. I like to start people in learning about BMI. I like to point people to our documentation. We tried to be really careful about writing up a nice description of what BMI is and why it's important and how you can make one. So let me risk the whole webinar by clicking on this link. Okay, good. All right. And maybe, Tien, if you could put the link in the chat. That'd be really cool. Okay. Thank you. All right. So this is the document patient page for BMI. And it's long. We've got a lot of information here. What I wanted to show you was this table. All right. So this table of BMI functions. So this is what the BMI is. It's about 30 functions. Now, you don't have to add all of them. Some of them depend upon what sort of grid you're using. But there's 30 functions. It's a bit of work. You can see names like initialize. So the idea of initialize is it would start a model. You can see update. That advances the model by one time step. There's finalize that's used to stop a model. There's also getters and setters. You can get values or set values in the model. All right. So you can see they have pretty readable names as well. All right. Let's go back. Let me get a quick drink. I'm a little too far. There we go. All right. So I've given you kind of a high-level overview of what BMI is. It's a set of functions. But my next bullet here is what is the benefit of a BMI? Why would you want to include a BMI with your model? And to do this, I've put a picture of my wife, Subaru, on the side here. It's going to make me think. So Tia, I have a question for you. You come to the office. We practice this, so she's smiling. When you come to the office, how do you get to the office usually? I usually drive a car. Oh, okay. So where did you learn how to drive a car? I learned that I'm back in China and got my first driver's license in China. Okay. Cool. All right. So the thing is that you're in the States right now and you're able to drive a car just fine, right? So that's kind of cool. So the neat thing is that Tien has benefited from a standard in the sense that cars have steering wheels, cars have accelerator pedals and brake pedals. So there's a standard. So the fact that Tien learned how to drive a car in China and was able to come to the States and drive a car just fine here in Boulder, Colorado is really because of standards. And so BMI is a standard. And the idea is that if you have the same set of functions for any model, it makes it easier. Once you've seen one BMI, you've seen them all because it's the same set of functions. All right. So this is the benefit of a BMI. And I think I garbled that a little bit, but I promise we can talk about that more. And again, please look at that documentation. I think we did a nicer job writing it up there as well. All right. So there's been so much prelude to the content of our webinar. So my last bullet is here. Well, how can a BMI apply to data? This is the basic model interface, not the basic data interface. Well, the thing is, if you think about it, a data set has many analogs to a model. So for example, I think of the initialize function. Initialize is used to start a model. Initialize could be used analogously to open a data set, to open a file. Finalize could be used to close a file. We could use the update function to move to the next time slice, for example, in a file. We could use the get value function to pull out the data from a given time slice. So there are many direct analogs between a model and a data set. And BMI, we think, can apply here. So this is the topic of our webinar, then the idea of a data component. So the way that we've imagined and the way we've implemented this idea of a data component at CSDMS is just a Python package. And it provides access to a data set through a BMI. Now, the data set will have its own API. And it may have its own, it'll have its own details, and everyone's probably different. But because it has a BMI, they'll be the same across different data sets. So we've done some work on this. Let's see what we've done so far. So I'm going to click a link again. All right. And Tien, if you could please put that in the chat. Awesome. I'd like to put it way ahead of me. Thank you for doing that. All right. So you can see on the CSDMS page, we have a page of data components written by mostly by Tien. Tien's the expert. I wrote a couple because I looked at what Tien did. We've got a contribution from Rich in the community, which is awesome. All right. So just to give a higher level look at this, you can see that there's a number of particular data sets, as well as some broader data sets as well. Each of these would have their own API. If I had to go in, and well, Tien will show this, but if I had to go get some ERA5 data, for example, for VCMWF, it has its own interface to access. I don't know what that interface is right now. I imagine it's probably NetCDF. There's probably something wrapped around NetCDF. But I don't have to know because there's a data component, all I need to know are the BMI functions. I know initialize, finalize, update, get value, for example. So I don't have to even know that it's a NetCDF file or a GRIB file, for example. All I need is the data component with its BMI. All right. So these are some of the ones that we've written so far. Let me go back. Oops. There we go. All right. So data components then are also a part of the CSDMS workbench. So we didn't mention this in the beginning, but just to circle back to that first slide of ours, data components are going to be a part of the whole ecosystem that we have at CSDMS for building, running, and coupling models. All right. So now I'm going to turn it back to Tien, who, again, is the expert, can talk us a little bit about how to create a data component. Thank you, Mark. And thanks for talking about the basic model interface and showing some data components. Actually, we hope the community can also contribute your own data components, especially when you have a large data set and you want more people to use them and or couple your data with other models, which is under the time team modeling framework. You can also write your own data components. And today I'm going to use the soil grade data component as an example. This data component fetches the global graded soil information from the soil grid system. And this system provides the spatial distribution of the sum of the soil properties, such as the bulk density, clay, sand, and soil content, something like that. But they have some more other soil properties. Can you go to the next slide? So when I create the soil-grade Python package, it includes the soil-grade.py file. In this file, it has a class that downloads the soil data sets from the soil-grade system using their web coverage service. And there is also a BMI.py file. And this file includes another class that wraps the class from the soil-grade.py file with the basic model interface. After I finish the soil-grade package, I use the Bibleizer to run over this package and generate the PyMT soil-grade package. Mark, would you want to add more and talk about what Bibleizer is? Oh, yeah, that's good. So we talked about PyMT already. The Bibleizer is another tool that's in the CSD Most Workbench. And it's used to wrap a BMI-wrapped model or data set in any of our supported languages, like Python, C, C++, or Fortran. And it makes it into a Python package that you can import in PyMT. So the Bibleizer, we actually have a paper in Joss. It's under review. It's almost done, so it should be out pretty soon. Okay, cool. Oh, can I just add one thing? One thing I want to mention about that, actually, you can directly use the service Python package to download the data if you don't need to couple your data sets with some of the model components under the PyMT modeling framework. Okay, next slide. So after you create your data component, you may want to create some tutorial notebooks and share with others and help them easily run them and learn your data component. And the CSD Most at HydroShare capability can help you achieve this goal. So I want to provide a little bit of background about what HydroShare is. So HydroShare is a web-based hydrologic information system for people to share their data models or tools and collaborate and solve research problems. Next slide. And in HydroShare, you can put any kind of files for sharing. And there are some additional data functions for several data types, such as time series, geographic feature, or geographic raster, and also multi-dimensional space time data. HydroShare also provides data publication functionalities. When you publish your data or models or even your GPU notebooks, you can get a DOI and cite it in your research paper. Next slide. So in HydroShare, there are some social functions to encourage collaboration. One of it is the resource access control. So when you use that, you can only choose the trusted HydroShare users to get your data. But you can also put your data sets as public so anyone can discover and access them. HydroShare also supports several web applications for data analysis, visualization, and modeling. And one of the examples is the quasi-duper hub, which is shown in this figure at the bottom right. In quasi-duper hub, on the left figure, you will see in the quasi-duper hub, there are several server options. One of them is the CSDMS workbench. In this server option, we installed the PymTN LAN lab, which is from the CSDMS workbench. And we also have some scientific Python packages installed to support analysis and realization, such as Mapwell Lib, X-Array, and NumPy, and some other Python packages. So we also put many tutorial notebooks for PymT and LAN lab for people to discover them from HydroShare and run them using the quasi-duper hub so that they don't need to install anything and directly learn how to use PymT or LAN lab.  Finger crossed and then hope for the best. Be perfect. I will stop sharing. I will start sharing. Can you guys see my screen? Yep, it's all good. Great, cool. So here's the HydroShare homepage. If I go to discover and type soil grades, and you will find out the Jupyter notebooks for this data component. And this is the resource landing page for the Jupyter notebooks of the soil grade data component. You can enter the abstract information, the keywords, and also those are the resource files. One is for the soil grade Python package and one is for the PymT soil grade Python package. Those two are the tutorial notebooks for them. And if you click on open with and select quasi-duper hub and remember to select CSDMS Revenge because only this eruption are installing the correct Python packages for you to run those notebooks and click on start. This process really takes two to three minutes to load. So probably you need to be a little bit patient. I'm just going to sit here and stare awkwardly at the screen waiting for it to load. Tien, we were supposed to rehearse some small talk. I forgot to do that. Yeah. So, oh, okay. Yeah, so one thing maybe I can mention later. Okay. Yeah, so I will open the soil grade Jupyter notebook. Okay. In this tutorial, it includes three sections. One is the brief introduction and package installation. The second section is to show two examples how to use the soil grade data component to download data sets for realization. The third section is to guide you right to your own code and download different soil property data sets. The first step is to install the soil grade Python package. And in a quasi-duper you are allowed to install your own Python packages. This is very helpful because when there is a new component, whether it's a model component or data component, we don't need to update the CSDMS workbench server option. You can just add a combined for package installation in your Jupyter notebook. So, in the second section, it will show two examples. As I have shown in the soil grade package, there are two Python files. The soil grade class is in the soil grade.py file. And the BMI soil grade class is in the BMI.py file. The first class is designed for users to download data sets. And the BMI soil grade class actually wraps the soil grade class with a basic model interface. So, the first example is to use the soil grade class to download the data. In this class, it includes the get coverage data method to access the soil property data from the soil grade system. And the first cell actually is trying to download the soil page data for the study area in Senegal. If you want to learn more about the details of the different parameters, you can click on the parameter setting link. It will show more details about that. So, let's run the first cell and download the data set. Okay. The second cell is trying to show the map data information. And you can see it shows the variable name, units, and the corresponding service URL information. And the third cell is to make a plot of this data set. Okay. And the second example is to use the BMI service class to download the same data set. Actually, BMI are not designed for people to use. If you want to learn how to use the data component under the PymT modeling framework, you're welcome to try out with the PymT soil grade Jupyter notebook. But here, I want to show you how to use some of the BMI methods to access the data set as well as the map data information. When you use the BMI, the first step is to use the configuration file and to initiate a data component. Actually, this step is trying to download the data set from the service system. Okay. If you have interest, want to know what is in this configure file, you can show that. So, it includes the parameter information, which is exactly the same that we have seen from this method. Okay. This cell actually is using the variable related methods from the BMI soil grade class to check the variable information of this soil data set. It's actually like doing the retrieving the map data information of the soil data sets, like variable name, unit, location, type, and its associated variable grade. And this helps to use the grid related methods of the class to check the grid map data information. Like the grid rank, size, the shape, spacing, and also its lower left origin coordinate information. And this type of step is using the GAT value method from the BMI method to retrieve the soil grade data set. The last cell is to do the visualization of the data set. So, this is exactly the same as the one we have seen from the example one. The third section is to guide you, write your own code, but I'm not going to show the details. Only one thing to mention is that when you write your code, actually, you can double click the section to check with the answer to see if it is same as the answer we provided. Okay. So, here is the PIMT soil grades. I won't go into the details, but I want to mention if you look into the code, you will find out it's very similar as what I've shown for the BMI soil grade class to access the map data as well as the data sets. Yeah. And you will see the plotting are same too. I think that's all my demo. I will stop sharing. Okay. Yeah. And I can start sharing again. Okay. While I'm doing this, one little note is that, one little note is that, you saw in Tien's notebooks, when she used the API from soil grids, it was only a couple lines, but when she used the BMI, it was several lines of code and that's kind of the trade-off. Maybe the BMI, because it has to be more general, it takes more lines of code in order to do the same task. Another little interesting thing too is that because the BMI is written in Python, the BMI and the PyMT version of the soil grids component are very similar. Like, if you inspect Tien's BMI notebook and the PyMT notebook, you'll see code that is rather similar. Again, and that's because they're both Python. If we had written the data component in C, for example, then they'd be quite a bit different. Yeah. I also put the hydro shear links for LaLa, PyMT and also soil grids, Jupyter notebooks. That is the information I want to talk about while loading the container, but since it looks faster, I just put it here. Yeah. So fast. Yeah. I did a little bit test before the webinar. That is why. All right. So let's take a look. Here's a summary of what we see today in the webinar. All right. So one, the concept of BMI, that's basic model interface, can be extended to data sets and it works pretty well. It's really kind of a neat idea. Okay. So two, a data component is a Python package. And I should mention as well, we know we choose Python because we basically chose Python as our hub language at CSDMS. We could have done this in other languages, but we have just decided to standardize on Python. All right. So a data component is a Python package that provides access to a data set through a BMI. The data set will have its own API, but we're not going to care about that as a user. We can just use the BMI instead for simplicity. All right. Three, data components can be coupled with models in a framework such as PyMT or LandLab. Now, we didn't show much of that today, but that is possible. And then four, we have developed a set of data components. Mostly Tien has done that. We've also had some contributions to the community. Yeah, Rich. But you guys can make this as well. And it's really cool if we have a big collection of data components, we'll make it easier for other people to access data and use them within a coupling framework. All right. So those are the takeaways from today's webinar. Tien, is there anything else you can think of? Yeah. I put some information in the chat, especially for people who have an interest to create your own data component. So after you finish that, you actually can create a VikiLab from our CSMS website as the lab information and help the students and other researchers to learn about your data component. And we also have the model rappel. When you have your new data component available, you can actually register your data components in there. And they will be shown on the list in the future, like when we have shown the country, we have seven. Hopefully, we'll see more from the community. Yeah, that's my note. Cool. All right. Thanks, Tien. Right. Is that it then? Yeah, I think so. All right. Thanks, everybody. Thanks for watching. We'll stick around and we'll try to answer questions. If you'd like, we're going to try to answer questions. Okay. If you'd like, you can ask questions in the chat or you can just unmute your mic and ask us directly. Yeah. Can we ask questions, please? Yeah. Okay. Thank you, Tien, and Bob for this nice presentation, to be honest with you. So my first question to you, is your code limited to a specific data source in order to download the soil properties? Or you can download the soil properties from any website? And what kind of the soil properties it's like, for example, I mean, what is the type of the data? It is a graded data or it's boring data, and you consider in your code in order to make interpolation between that in order to produce a map-based soil. So this is my main question for you. Okay. Thanks a lot for your questions. I will try to answer the ones I remember. If I miss someone, you can just remind me. First, for the soil data sets, this data component is only working on the data sets provided by the soil grid system. I can put the systems link to you. But if you want to create another data component downloading the soil data sets from other system, that would be totally fine. Or if you have your own soil data sets and you want to create a data component, that would be fine. So there's no limitation, what kind of data you want to wrap with as a data component. And specifically for this soil property data set is raster data. So it's covering the whole global scale. They have more soil property data sets and not just limited to the ones I have mentioned. I can send you the link and can check into the details and see if there are some properties you have interest in. Any other questions that I missed? Or do I answer your question? Yeah, you answered my question. Thank you, Thayan. And to be honest, why I'm asking this question, because you know, we are using different types of the hydrological modeling, particularly at continental scale, like the water, hydro, water flow, whatever. And you know, from each model to another model, maybe the soil properties, I don't know the shape of the data, the type of the data, it could be different. So the question that for example, if I want to use or create my own data for the soil properties in order to feed the water hydro model, is that enough? Or do I need to look at other data sources in order to obtain all the data that I need to feed the water hydro model? For example, while hydro model is one example of the hydrological model. Or does this data that you are already or the tools that you created, we can obtain all the soil properties that the hydrological modeling needs? So it depends what kind of soil properties the model requires. And then you need to look into the soil grid system and see if that system provides the corresponding soil property data. Am I answering your question? Yes, yes. Thank you, I appreciate that. Thank you. Okay, I will put the soil grid system information in the chat. So you can check whether your data is available to be used as the input for your model. And yeah. And then you can use the, if they have the corresponding properties, then you can use the soil waste Python package to download the data set. I see there's a question from Hunter in the chat as well. I think I can take this one, Tien, you can back me up on this if you'd like. So Hunter asks, would you suggest model development in land lab in another repository such as GitHub instead of HydroShare for version control? Or does HydroShare works similarly? So I think the answer to the question is, yeah, if you're going to do some development in land lab, it should be in a GitHub repository. HydroShare would be more of a place for you to host the result, to host running the model. So yeah, is that sound good? So yeah, development in, and use a GitHub repository for your source code, but use HydroShare then in order to distribute your model and to let others use it. Yeah, or if you, after you finish one land lab component using GitHub and maybe you want to create some Jupyter notebooks and show how to use your land lab component, then you can share your Jupyter notebooks in HydroShare and others can easily access, discover them and write them on Quasi Jupyter Hub. Okay, thank you, Tien. Yeah. Okay, anyone else? Any other questions? Okay. Well, thank you very much for your tending, right? Yeah, thank you so much. All right, bye-bye.