Hi, I'm Realtor Sara Maro with Cell State Peak Realty. Welcome to episode one of Proper Tea Time. Joining me today is Colin Argus from the Longmont Downtown Development Authority. And we're here to discuss that there are a lot of great areas of Colorado, but today we're going to be discussing why Longmont. As a Realtor, I've noticed lately how long-time residents and natives simply don't realize how expensive their hometown is getting until they decide to move. Let's face it, living in a great town has a cost. That's how supply and demand works. But what characteristics make a town a great place to live in the first place, and which of these assets impact our assets? In other words, how do these characteristics increase our home values? Is it the mountain views, the arts and rec, does the quality of schools and the crime rate and family-friendly vibe in the neighborhoods dictate our purchase prices, or does it really boil down to location, jobs, and median income? In a nutshell, Coloradans thought Boulder was getting expensive at $600,000 back in 2013, and those very neighborhoods only eight years later are valued at well over 1.5 million now. And while I'm not here with a crystal ball or even prepared to give educated predictions, one key indicator that Longmont is becoming the next bolder is that we're not building a lot of new homes here. We really don't have that much land for that, frankly. So we're sprucing up what we've got, and when you see a downtown revamp itself the way that we are, you realize, oh, we have innate value, and people want access to the face-lifted resources that we have. Homes do need to be built, and naturally developments are starting to spread outward. But what you're paying for when you arrive here, even in the outskirts, is largely due to all the development in the face-lift that we're doing right in the downtown area. And we're really not a metropolitan hub in look, feel, or cost here in Longmont, but that's really quite attractive in our post-pandemic world. Hi, Colin. Hi, Sarah. So let's start off by you telling us a little bit about what makes downtown's Longmont area so unique. Absolutely. There's a lot of old towns in this state. What's so great about ours? Yeah, well, thanks for asking. I feel like a couple of words that come up often when people ask about downtown or talk about downtown is real and authentic. And that relates to the people that are here. It relates to the small businesses that are here. We don't have a lot of chains in downtown Longmont, really. It's all a lot of locally-owned small businesses, and those small business owners are kind of the heartbeat of our downtown community, which is really great. So I feel like that's a big thing that sets Longmont apart from a lot of communities around here. We had a consultant who came in and spoke to us, and he works at communities all over the front range and even beyond Colorado. But he said Longmont really feels like one of the last kind of freestanding cities and freestanding communities along the front range that hasn't been swallowed up as a suburb of Denver, Boulder, Fort Collins. I think that's a point of pride as well. So why is ours? I've noticed ours is also larger in size, and therefore more entrepreneurs can come in and sort of space. Like, what can you do in Longmont that you can't do downtown elsewhere? Sure, yeah. So it's a unique downtown for sure. It's very, like you said, it's long and linear. It's big. It's expansive. And part of that is kind of dating back to the founding of the city, really, of the city of Longmont town of Longmont back then. But some settlers came over from Chicago and formed the Chicago Colorado Colony. And part of the land agreement was that they received a plot of land for their home, but then they also received space on Main Street to start their business. And so some of those businesses are still here today, or sorry, the buildings are still here today. So one example is the used book emporium. That's the oldest currently standing building in Longmont. They've still got a big hand crank freight elevator in the back. And then another one is MA's Love. Used to be actually JC Penney's meat market. JC Penney started the retail business and kind of learned the dry goods trade here in Longmont. So that's kind of a fun point of history in Longmont. But yeah, I feel like that kind of influenced the character and the historic charm that Longmont has. We are a certified historic district. We're also a Colorado certified creative district. So there's a lot of different things happening downtown, a lot of vibrancy, and yeah, a lot of things to enjoy. Awesome, thank you for sharing all of that. Would you speak similarly, since we're on that topic of entrepreneurship and business growth, could you speak to the current volume growth that we're seeing in Longmont? What's driving that? I've noticed some new really popular businesses coming into town, expansions, that sort of thing. What have you noticed? And how is that impacting the space we've got? Sure, yeah, yeah. There's definitely been an influx of people, but also businesses as well, especially over the last five or 10 years. There's been a lot of interest from developers, multi-use kind of development projects, but as well as just businesses that have moved here from other communities. There's been a few businesses that have found downtown Longmont from places like Boulder and Louisville. I just really liked the community-oriented aspects of downtown and of Longmont as a whole. So I think that's been a big draw for those businesses is the community feel. There's also a really strong entrepreneurial spirit here in Longmont, and people want to share their talents and their experiences and their knowledge with the rest of the community. So I feel like there's a good mix of people taking their dreams and moving forward with them and starting, but also people finding Longmont from other communities and feeling like this is the right place for them. So are you seeing, I've noticed there are several family businesses even, mom and pop shops, or are you finding there's young, is it a combination of young entrepreneurs coming here? Is it people who have owned forever? Is it both? Yeah, I think it's a mix of all that really. We've got, like you said, the mom and pop shops that have been here on Main Street for 30, 40, 50 years here in Longmont. And then there's other family-owned businesses that have relocated, like I mentioned. There's actually a couple new ones gonna be opening here in the near future on Main Street that are family businesses that have been in business for a long time that popped up here on Main Street. But then also, yeah, I feel like Longmont has a unique opportunity in the space that's available. There's a large variety of different types of spaces available. And I think, especially over the past year, the demand for space has changed a lot. There's been so many changes with office space and how people are looking at brick and mortar locations. So I think we have a pretty diverse offering of spaces available here in Longmont. Is it mostly craft breweries, restaurants, new IT tech? What are you seeing? That's a good question. Food and beverages has always been huge here in Longmont and the craft beverage scene for sure is probably one. Alive and well. Certainly alive and well. You could say that again. Within Longmont, we've got tons, even just within downtown, we've got, I don't know, six, seven breweries. We've got a couple distilleries. We've got a cidery. And yeah, Longmont certainly is a destination for craft beer and craft cocktails. And there's nationally recognized restaurants. We've had Guy Fieri get a stop here with his diners at Drive-Ins and Dives. And the Travel Channel, I think, featured Georgia Boys' barbecue. I know the roost was on Guy Fieri's show. There's just a bunch of really wonderful, unique craft food and beverage establishments here in Longmont. So that's always been a really strong component of the business community here in Longmont. That tech piece is also growing strong. We've had a couple different tech companies that moved here over the past few years and have taken office space above a bank downtown or just utilized unique properties for that as well. So again, it's a mix, so yeah, hard to say, but all of that is alive and well for sure. Now I know I'm the realtor, but let's step away from old town, downtown area for a second. Can you speak to what makes our neighborhood so desirable for families, for singles, and for seniors? I've noticed as a realtor, we're getting an influx of all of the above. What do you notice about the outskirts, if you will? Sure, sure. Well, downtown is definitely my area of expertise, but I also live here in Longmont. I grew up in Bertha just down the road, and so not a lot to do in Bertha back when I was growing up, so we came to Longmont a lot and have enjoyed it, and my wife and I have owned a house here since 2015. So yeah, Longmont has a ton to offer. I feel like one unique aspect is kind of, it's a pretty big city of close to 100,000 people now, but it's really got that small town charm, community feel. It's very welcoming and inclusive for anybody and everybody, so I think that's a big draw. It's also, we're so centrally located close to the mountains, close to Fort Collins, close to Denver, so it's easy access to really anything you wanna do, beautiful views. I mean, I live kind of close to McIntosh Lake, and I go out there and I'm just blown away with how lucky I am to live somewhere where you can see those views within 10 or 15 minutes of your house. Also, the city amenities that exist, they're always improving them, they're always thinking of others, but the museum, the library, multiple rec center facilities, there's so much to be done in Longmont and tons of programming for families and the senior center is very active as well, and there's a growing kind of nightlife along with the craft beverage scene. There's kind of a growing nightlife scene for those younger folks, so there really is lots to do for everybody and I think anybody could probably find what they like and something they'd like to do here in Longmont. Yeah, I definitely like the arts and rec aspect of things. I mean, it's nice being near Boulder, Denver and Fort Collins, but I almost feel like we're a standalone city on our, if I'm gonna play music or perform, I don't have to go to Fort Collins. I kinda like that. Absolutely. There's a live music scene here. Yeah, live music is another huge one in addition to the craft beverages and I think it's those kind of go hand in hand for the most part, but. Quite agree. Yeah, you know, there's a ton of awesome local talent here in Longmont. One event that I've worked on in the past is the Winter Walk About Music Showcase and so we've been able to showcase, I think we had close to 50 performances in 2020. We did an event in 2020, believe it or not.  So that was in February of 2020 before everything hit the fan. But yeah, it was really great to showcase all of the amazing local talented musicians here. And yeah, I mean. Thank you. I was wondering. Yeah, absolutely. Yeah, thanks for playing. We look forward to having you back. Thank you, thank you.  So music and creativity is a big part of the kind of Longmont spirit and Longmont as a whole. Wonderful. I know you just had a baby. I don't know a lot about this, the kid scene, but can you speak to, I'm known as a realtor, what makes our school system preferred over the school systems in the neighboring towns and in the area? Yeah, so. Why do people go so Nazi for that? Yeah. My little guy's only 11 months old today, actually, happy birthday, James, and he won't see this for years. Ah, happy birthday. Thank you. You haven't enrolled him anywhere yet? No, not yet. Not yet. But we're gonna hop on that open enrollment as soon as he's eligible, because that's... Is that a big draw? That's one, yeah. I believe that's one huge draw for the St. Mary Valley School District is that open enrollment choice. You don't have to live in the heart of Old Town to go to Central Elementary. You can live anywhere here. Right, you can find a place that works for you and a location that works for you at a price point that works for you, but also take advantage of the school system as a whole. And you know, they've also got this wonderful innovation center out by the museum that focuses on the STEAM STEM aspects, science, technology, engineering, mathematics. And there's a lot of IB opportunities, honors opportunities. So really, I think St. Mary Valley School District is rivals any top school system in the country for those opportunities for kids. Great. And you said you've owned your home in Longmont for a while. Which neighborhood are you in? We're right by Lou Miller Park. It's called Longmont Estates is our neighborhood. So just behind Longmont, I'm at a hospital there. Right, you said you're near the like highly desirable area. Yes, absolutely. I joke with my wife that when we were looking at, when we put an offer in, I was like, you know, if anything happens, I fall off the roof or something. I'll just crawl over the hospital. We'll be fine, it's great. But no, we love the neighborhood that we're in. It itself is just a great mix of wonderful people. They're so real, so welcoming, so kind. Mix of ages, you know, my one next door neighbor has been that lived there for 40, 50 years. Wow. With his family race, it's his whole family there, and now he's retired. My neighbor on the other side, she is a semi-retired and just moved in around the same time we did, but just really found Longmont to be the place that she wanted to be. And then we've also got some younger families that have moved in next to us. It's just really a great, great mix of people and everybody gets along really well. So that's a nice segue. You heard me say earlier that we don't really realize how quickly our properties are appreciating and gaining value until we look around and it's time for us to move. Could you speak to the fact that only eight years ago, some of the more desirable areas of Boulder, we thought they were expensive at 5,600,000, and now they're up around 1.5 million in a short period of time. First of all, do you see that sort of, from where you're standing and you're in your employment, do you see that happening in Longmont? And second off, how are we gonna deal with that? How are we gonna afford to live here? That's the question of the year, right? Yeah, it's hard to say. Housing costs are certainly rising all around the region and the state and the country for both good and bad. But I feel like Longmont is able to maybe stay a little bit more even than some of the other communities. I feel like prices are skyrocketing other places and prices are certainly rising here, but at kind of a more maybe sustainable amount. And I know, obviously we're working to address the supply and demand issue with lots of new builds. There's lots of new construction going on. As you mentioned, we don't have necessarily a lot of space to expand outward, but I think more efficient use of space and some of those new builds should help to address that. So I feel like Longmont has a good chance to be a little bit more, have a little bit more stability and be a little bit less volatile, but you're the expert. Thank you for that. Well, yeah, there's certainly talk of us being the next NYWA, the next gun barrel, the next Boulder and just, I guess we all just have to recalibrate if that happens and start making more money. Well, I know Boulder County is not gonna go down in desirability, that's for sure. It's gonna be a wonderful place to live for many years to come. So we've got that to look forward to for sure. Thank you so much for your time. Thank you for having me. I appreciate it. You're very welcome. That's the proper tea.


Friends, starting from this lecture for the rest of the course we will be looking at the non-ideal reactors, how to characterize non-ideality in reactors. So in further we will be particularly looking at the distribution of residence time for chemical reactors, particularly we are looking at the distribution of residence time. Now it turns out that the ideal reactors that is the all the reactors that we have looked at so far they are all ideal reactors that is the plug flow and the mixed flow reactors. These are all ideal reactors and it turns out that the real world reactors they really do not behave like the plug flow or the mixed flow reactors. So the real world reactors are slightly different, real world reactors they behave differently and it is actually important to diagnose and understand when they deviate from ideal behavior. So we have seen how to write performance equations for ideal reactors like plug flow reactors or under mixed conditions and we have also we also know how to write performance equation for CSTR which is not necessarily an ideal situation, we will see what is meant by ideal situation and how where the CSTR fall into that category. So it is important to diagnose it is important to diagnose the deviation from the ideal behavior. So suppose if there is a reactor if I assume that it is a plug flow reactor and I write a performance equation and I find out what is the concentration profile of the reactor and let us say in the effluent that is after the stream leaves the reactor. Now the real world reactor perhaps may not attain that kind of a conversion and that sort of indicates that the reactor does not behave like a plug flow reactor. So the question is how do I diagnose such kind of a deviation. Now suppose if I have diagnosed such kind of a deviation and how do I characterize such a reactor which does not behave like the ideal reactor such as the plug flow and the mixed flow reactors. So the objective of the rest of the syllabus of the course is basically to look at analyze and analyze and characterize non-ideal reactor behavior. So that is going to be the objective for the rest of the course. So now the key piece of information that is actually used in order to analyze and characterize non-ideal reactor behavior is the distribution of residence time. Residence time distribution of a reactor quantifies the time spent by various fluid particles in the reactor and is a characteristic of mixing that occurs in the reactor. So in the rest of this lecture we are going to look at several examples of a non-ideal behavior that has been observed experimentally and observed in real systems and also look at some of the definitions of what is residence time and what are the different ways to capture the residence time distribution etc. So that is going to be the objective of this particular lecture. So the distribution of residence time is actually used to diagnose the reactor operation problems. It is also used to predict conversion of a new reaction when conducted in an existing reactor. So these two are important aspects if suppose if there is a reactor that is already being characterized. Now if you want to conduct a new reaction in that reactor is it possible to predict the behavior of that particular reaction in that reactor. So that is an important question and in addition to that suppose if there is an experiment that has been conducted in a small scale and then we want to scale it up to a next level to increase the productivity of that particular product which is desired then it is important to actually characterize the non-ideal behavior and it helps in scaling up the reactors. So let us look at a specific case of gas liquid CSTR. Suppose I take a tank and let us say that the gas A is being bubbled through the liquid. So let us say that the liquid is filled, let us say the tank is filled with liquid and bubble A is actually bubbled through this liquid inside and then it leaves the reactor from the top. So that is gas A which is actually entering from the bottom and it is being bubbled inside and then it leaves from the top of the reactor. Now suppose there is another liquid B which is now flowing through this reactor and the gas is simultaneously bubbled through this liquid. So the liquid leaves from the exit stream for the liquid. So now so A species A is actually being bubbled and species B is actually the liquid phase which is going through the reactor. So now one can actually realize that there are three processes which are actually occurring here. So remember this is a gas liquid reactor. So the reaction is actually occurring between the species A which is in the gas phase. The reaction is between species A in the gas phase and species B in the liquid phase and that leads to formation of certain products. So now if this reaction has to happen the species A which is present in the gas phase has to diffuse and come to the interface between the liquid and the gas stream. So the first process is the gas diffusion to the gas liquid interface. Now suppose I assume that the gas is immiscible in the liquid then the reaction has to occur at the gas liquid interface. So there is an interface between the gas stream which is present inside the bubbles and the fluid stream which is actually present around the bubbles and so therefore the gas species has to diffuse from the bulk inside the bubble to the gas liquid interface in order for it to get in contact with the liquid with which it has to react. And similarly, so this is basically diffusion of species A and similarly the species B has to actually undergo diffusion that should has to be a diffusion of species B to the gas liquid interface. So only after this these two processes have occurred the reaction between these two species can occur. So therefore the third step is the reaction between species A and species B at the gas liquid interface. It has been assumed that the reaction occurs at the interface however the reaction need not be confined to the interface as where the cases that were covered in lecture 26. So these are the three processes which are actually occurring in order for the reaction to actually occur. Now suppose we can assume that the liquid which is actually flowing from the top of the tank so as if you look at the tank again so the liquid which is actually flowing from the top of the tank through the tank and leaves the bottom of the liquid. So this is this can be assumed as a continuous liquid phase. So we can assume that the liquid is actually a continuous phase. So the liquid is actually continuously flowing continuously flowing and in fact it perhaps it can also be assumed that it is well mixed it can be assumed that it may be well mixed that is the concentration of the species in the liquid phase is almost uniform inside the reactor. Now that is not really true but may be we can assume for the time being that it is well mixed in order to actually appreciate what is happening inside the gas liquid CSTR and particularly in order to appreciate the nature of the non-ideal behavior. Although in reality even the liquid phase will not necessarily be well mixed but if it is a continuous phase and it may be assumed to be well mixed for the time being. So the question is what about gas phase? In fact comparing gas phase the liquid phase can actually easily be assumed as a well mixed phase. Now what about gas phase? Before we understand what happens in the gas phase let us try to actually understand how the what are the different properties that actually control the reaction rate. In fact it is that which gives an insight as to what is the nature of the fluid flow in the gas phase. So the reaction rate is actually proportional to the surface area. Suppose AB is the surface area of a particular bubble. So remember that the gas which is actually flowing from the bottom to and leaves the top of the reactor is actually bubbled inside. So it forms bubbles and then the bubbles raise inside the liquid stream and then while it raises the reaction occurs in the gas liquid interface and then the bubble leaves the reactor. So the reaction rate is actually proportional to the surface area of the bubble which is available for reaction. It is the surface area of the bubble which is actually available for the reaction to occur. Now the surface area of the bubble which is available for the reaction what does it depend upon? It actually depends upon the amount of time that the bubble actually spends inside the reactor. So therefore the surface area of the bubble available. So remember it is not the surface area just the surface area of the bubble it is the surface area of the bubble which is available for the reaction to occur when the bubble is actually rising from the bottom to the top of the reactor and that depends upon the time spent. So that depends upon the amount of time that the bubble actually spends inside the reactor. So the gas bubbles when it is actually generated when it is passed into the liquid they are generally not of same size so different gas bubbles are going to be of different sizes. So therefore so different size bubbles one can expect different size bubbles to be created and these different sizes are actually simultaneously they are raising up and because the bubbles are of different sizes different bubbles are going to raise at different velocities. So therefore clearly some bubbles may actually escape immediately. So some bubbles actually they will escape immediately which means as soon as they are created they will quickly go to the top of the liquid stream and then they will leave the reactor. And so the amount of time that these bubbles would have spent which have left immediately will be extremely small. Now others might spend more time other bubbles may spend more time inside the reactor and as a result of this the amount of species which is present in the gas phase can actually get completely consumed because the bubble is now spending sufficient time inside the reactor for all of the reactant to actually diffuse from the gas phase and reach the gas liquid interface and actually contact the liquid phase species in the liquid phase and the reaction to occur. So therefore some of these bubbles gets completely converted. So the gas species present in some of these bubbles gets completely converted. So there can be complete conversion or complete consumption of all the species in each of these bubbles. So when I say complete conversion it means that in one bubble which actually spends more time inside the reactor or in the bubble in bubble which actually spends more time inside the sufficiently more time inside the reactor. So that is what is meant by complete conversion in that particular bubble. So now as a result of this observation that different bubbles spend different amount of time inside the reactor and that some bubbles actually leave immediately and some bubbles actually spend more time in order for all the reactants present inside the bubble to have undergone reaction or to get consumed the gas phase cannot be assumed as well mixed cannot be considered as well mixed. So therefore it is important to consider the amount of time spent by the bubble inside the reactor while designing these kinds of gas liquid CSTRs. So just to define the time spent by the bubbles in the reactor is called bubble residence time that is called the bubble residence time that is the amount of time spent by bubble inside the reactor. Now as observed earlier different bubbles spend different time different bubbles spend different time inside the reactor and therefore different molecules of species A species A will have with different residence time. So different molecules of species A although all of them would have actually come into the reactor at the same time because of this feature that different bubbles spend different amount of time inside the reactor different molecules of species A would also have different residence time. So clearly this is going to affect the reaction rate. It is important to note that RTD affects the conversion but does not affect the intrinsic reaction kinetics why is that because the reaction rate is a function of the available surface area and the available surface area depends upon the amount of time that is actually spent by the bubbles inside the reactor. So therefore if different molecules of species A they have different residence time that is going to clearly affect the extent of the reaction it is going to affect the reaction rate. And therefore it is important to consider it is important to consider this aspect of different bubbles having different residence time into the model analysis. So therefore it is important to incorporate the bubble residence time in the analysis in the analysis of such reactor and moreover it is actually important it is need to consider it is important that one considers the individual bubble individual bubble residence time and not just the average. So it is not sufficient to consider only the average residence time of the bubbles it is important to consider the residence time of each and every bubble which is actually created because the bubble is being sparsed into the liquid. So and as a result the net reaction rate as a result the net reaction rate is simply going to be sum of the reaction rate in individual bubbles individual bubbles and summed over all bubbles. So if there are 100 bubbles inside the reactor then one needs to actually find out what is the reaction rate in each of these 100 bubbles and sum them all and that gives you the net reaction rate inside the reactor. Net reaction rate here refers to the observed total reaction rate and not the intrinsic reaction rate. So now let us look at another example of a packed bed reactor.  So let us say that these are the catalyst particles which are actually present inside the reactor. So these are the catalyst particles which are actually packed inside and suppose if a fluid stream is actually flowing into the reactor let us say that it has a flat profile that means the velocity with which the fluid is actually flowing and the concentration with which the fluid is actually entering the stream is actually uniform across a given cross section. So suppose if it flows uniformly inside then because of the packing the resistance to flow is not going to be uniform at every location in a given cross section. So therefore one can observe that the fluid stream is now going to bend and then it is going to move through the crevices of the reactor and then they are going to leave from the other side. So clearly one can observe that the fluid behavior is not going to be uniform. So clearly the fluid flow is going to be a non-uniform fluid flow and why would that be the case? So some sections can actually offer more resistance. So some sections will offer more resistance to flow and as a result the channeling of fluids will occur. So as depicted here in some sections of the reactor the fluid will actually quickly go from the inlet to the exit of the reactor and leave the reactor while in the other sections they spend a lot more time. So clearly the amount of time that is spent by different molecules of the species that is entering the reactor is going to be different. Which means that there is going to be a distribution of residence time that is clearly going to be a distribution of residence time of the molecules which are actually entering the reactor and is participating in the reaction. So let us take another example of CSTR, a well mixed CSTR. Suppose we take a well mixed CSTR, so CSTR is a tank, that is a tank and it has a mixer. So let us assume that it is rotating in this direction and if the species is actually entering through, entering into the reactor, suppose this is the feed stream, species A is entering into the reactor at the feed, via the feed stream and let us say that the outlet of this reactor is at this location. So this is the out and this is the in stream and what happens is that often the inlet and the outlet streams of the reactor may actually be placed close to each other for various reasons and because of that what happens is that some of the fluids would actually quickly, some of the fluid that is entering the CSTR would actually quickly leave the reactor and in fact that process is called as bypassing. So the, some of the fluid particles which are actually entering into the reactor would actually bypass and leave the reactor and as a result what is created is some of the, some locations of the reactor are actually underutilized or unutilized and those zones are called as the dead zones. So what has been observed is that the, there is bypassing of fluid stream and because the inlet and outlet may be placed close to each other and so some of the fluid particles will quickly bypass and of course if one needs to model such kind of a reactor this has to be incorporated in the model and the second problem is the presence of a dead zone where the reactants are actually where the, where there is no reaction occurring in the dead zone so there is no reaction and not just that there is no reaction there is actually no exchange of materials from the dead zone to the well-mixed zone. So in addition to that no exchange of material from dead zone to, from dead zone to well-mixed zone. So clearly this suggests that there will be a distribution of residence time. So there will be distribution of residence time even in the case of where there is a CSTR with bypassing occurring inside the reactor. So all these three examples are actually a good motivation to think that there is a requirement for strategies to handle non-ideal behavior. So it is important to come up with strategies to handle the non-ideal behavior of reactors and this is very common because the ideal reactor such as the plug flow and the mixed flow reactors are commonly the not, they are not a good representation of the real world reactors. They do not behave exactly like the plug flow and the mixed flow and in fact we will see in one of the, in the future lectures that the one can actually clearly show using the residence time distribution that the real reactors do not necessarily behave like a plug flow or the mixed flow. So there are three concepts which are involved here. There are three concepts that one need to understand in order to come up with strategies to handle the non-ideal behavior of reactors. So the first one on that is the residence time distribution. So that is the amount of time that is actually spent by a given fluid particle inside the reactor and the distribution says how much time different fragments of the fluid particles are actually spending time inside the reactor. Then the second important aspect is the quality of mixing. So what is the extent of mixing that is actually undergoing inside the reactor due to various reasons. So one needs to understand and characterize the nature of extent of mixing in order to be able to understand the non-ideal behavior of reactors. And then the third aspect is basically to model used to describe such systems. So one needs to come up with ways by which one can actually model such kind of non-ideal behavior and so we are going to see that what are the various ways by which we can actually characterize the non-ideal behavior using these three concepts. And several examples will actually be shown to explain each of these concepts. And in fact, the RTD, the residence time distribution, it actually is used to describe, it describes the deviation from non-ideal behavior, from ideal behavior. So the residence time distribution actually describes the deviation or it sort of captures the deviation from the ideal flow behavior and we are going to look at how it captures in a short while. So the first step towards handling this, handling a real world reactor that is the actual reactor which may be present in an industry. So the first step is basically to model them as an ideal reactor. So the first step is to assume that the reactor is an ideal reactor. What it means is that it needs to be modeled either as a PFR or a CSTR. So one can actually model it as a plug flow reactor or a CSTR reactor. Remember that even in a CSTR, the residence time is not same for all the particles that actually goes through the reactor. However, it is a thoroughly perfectly well-mixed system. So it has certain ideal properties and we will see in a short while how to characterize them. And then suppose if this model does not predict the actual behavior of the reactor, then one needs to actually introduce the non-ideal behavior that is the non-ideal flow pattern. One needs to introduce the non-ideal flow pattern and in fact, in order to introduce a non-ideal flow pattern, one has to actually account for the ineffective contacting. While some of these fluid, for example, let us take the packed bed reactor case. The some of the fluid actually enters and leaves the reactor immediately because of the channeling effect. And so the contact that actually these fluid stream has with the catalyst particles present inside the reactor is not very effective. And therefore, one needs to account for such kind of ineffective contacting and also one needs to account for low conversion compared to ideal reactors. So one needs to account for these two factors if one has to introduce the non-ideal behavior into the ideal reactor model. So once we know once we know that the reactor behaves like a non-ideal reactor, then we need to account these two aspects into the model to capture the dynamics or the behavior of the reactor. Now the question is how do we account these two factors? So the first, so one needs to actually look at the macro mixing, macro mixing which is basically the residence time distribution which captures the macro mixing. One needs to account for macro mixing in the system and the other aspect is the micro mixing that is the, so this is the mixing at micro scale. So one needs to account for these two factors and in fact these two factors will actually help in characterizing the non-ideal behavior of the reactor. So let us first look at the residence time distribution which actually account for the macro mixing. So the residence time distribution was actually originally proposed by MacMullin and Weber in 1935. However it was actually ignored for nearly two decades and later Danckwerts came and actually gave a special structure to the residence time distribution and defined various types of possible distributions. So it was Danckwerts in 1953 gave structure to RTD. In fact he came and took the idea of MacMullin and Weber and developed it further and gave some special structure to RTD. Therefore most of the RTD work is actually attributed to the seminal work done by Danckwerts in 1953. So now we said that the plug flow reactor is an ideal reactor. So why is it an ideal reactor? So let us look at the ideal plug flow reactor. So plug flow reactor can actually be an ideal reactor under certain situations. So what are the properties of an ideal plug flow reactor? So in an ideal plug flow reactor all atoms and material, all atoms of the material have same residence time. So suppose there is a fluid which is actually flowing through a plug flow reactor then all fluid particles that actually entering the ideal plug flow reactor they spend exactly the same amount of time inside the reactor before they leave the plug flow reactor. So that is an important characteristic of an ideal plug flow reactor. And what about an ideal batch reactor? What about ideal batch reactor? So ideal batch reactor is one where all atoms inside has been in the reactor for same time. So all atoms that are actually present inside the batch reactor, ideal batch reactor they actually have been there, all atoms have been there for exactly the same amount of time as each other. And so therefore the time that is actually spent by these atoms inside the reactor is called the residence time and both these ideal plug flow reactor and the ideal batch reactor they actually have all the molecules inside they have exactly the same residence time. So there are actually only two classes of ideal reactors. In fact there are only two classes of reactors in which the residence time can actually be same. So it is the ideal plug flow and the ideal batch reactors, two classes with same residence time. So all other reactors there is going to be a distribution of residence time including CSTR. So suppose what happens in a CSTR, CSTR is something that has been commonly studied in this course in many different in the first course of the reaction engineering. And so what happens in a CSTR? How can we describe what is the nature of the residence time distribution in a CSTR? So suppose if we take a tank and then we feed a certain species into the tank which is undergoing a reaction. So if we consider the feed at a particular time, suppose we look take the feed at a particular time, suppose we consider feed at a certain time then as the feed stream actually enters into the reactor, the feed stream because it is a CSTR the feed stream immediately gets completely mixed with the materials which are already present inside the reactor. Now not just that the there may be a small fraction of the feed stream which is actually carried along with the fluid stream and it leaves the reactor. So therefore it is possible that some fluid stream, some fluid stream leaves immediately, some fluid stream actually leaves immediately. And so therefore the residence time of these fluid stream which actually leave the reactor immediately is going to be very small and in fact it is going to be different as compared to the residence time of others be other particles which are actually staying inside the reactor. So other particles they are going to stay for a much longer time and in fact most of the particles it has been observed that most of spend approximately the mean residence time. So most of the fluid particles the amount of time they spend inside the reactor is approximately equal to the mean residence time. So therefore the residence time distribution actually characterizes the extent of mixing. So in a CSTR the some fluid stream leaves immediately and the other they stay for a longer time which means that there is going to be a distribution and in fact the residence time distribution it characterizes the extent of mixing inside the reactor. So that is an important aspect it is a characteristic of mixing. So residence time distribution henceforth will be referred to as RTD and it is actually a characteristic of the mixing which is happening inside the reactor. So now if I take a plug flow reactor there is no axial mixing in a plug flow reactor. There is no axial mixing in a plug flow reactor which means that the if there is a tube and if it behaves like a plug flow reactor then the fluid stream which is actually entering inside they actually move like a plug which means that the fluid particles which is actually entering the reactor at a certain time they do not mix with the fluid particles which are actually entering just after it or just before it. So therefore there is no axial mixing of fluid particles inside the reactor if it behaves like a plug flow reactor and this can actually be seen this behavior or this aspect of no axial mixing can actually be seen in the residence time distribution. And it will be shown in one of the lectures in the one of the future lectures that for a plug flow reactor there is actually no axial mixing and that can be deciphered from the residence time distribution curve itself. And let us look at CSTR. So the CSTR is actually thoroughly mixed which means that the concentration of the species inside the reactor is going to be uniform at all times and so it is a thoroughly mixed system and that can also be seen in the residence time distribution of the reactor. So now and in fact one will observe which we will see in one of the future lectures is that the RTD of CSTR is actually very different from. So the residence time distribution observed for a CSTR is going to be very very different from the residence time distribution of a plug flow reactor. So at this point one needs to also know that not all residence time distributions are actually unique to the reactor type. So it does not mean that every reactor type has a unique residence time distribution and there is no 1 to 1 correlation, there is no one residence time distribution for a particular reactor type. So what it means is that different reactors can actually show identical residence time distribution. In fact different reactors of completely different configuration they can also very very similar residence time distribution. So residence time distribution can actually be used to decipher the nature of the functioning of that particular reactor or nature of the non-ideality that is present inside the reactor. So now the question is how do we detect these non-ideal behavior, how do we detect the residence time distribution experimentally. So it is actually possible to measure, it is possible to measure the residence time distribution and in fact it is experimentally determined using what is called a tracer. So suppose if there is a reactor a fluid stream is flowing through this reactor which is actually participating in a certain reaction which is getting consumed to form products. Now in order to find out what is the residence time distribution, in order to detect whether the reactor is ideal or non-ideal we need to know what is the residence time distribution and the way to do that is basically to use a tracer. So what is done is at time t equal to 0, so a tracer is introduced. So a tracer chemical is actually introduced and then monitor the tracer concentration as a function of time in a fluid. So one can actually measure the tracer concentration that actually is going to flow along with the fluid. So the tracer is introduced at the inlet of the reactor and the tracer is now going to be taken forward, taken by the fluid along the reactor and it is going to leave the reactor. So one can actually measure the concentration of the tracer material as it leaves the reactor and that way one can actually construct the residence time distribution. Now it is not possible to conduct such an experiment with any kind of tracer. The tracer has to have certain properties. So for example the tracer must actually satisfy certain important, must have certain important properties in order for it to be used to measure the residence time distribution and these properties are basically they have to be non-reactive species, they have to be non-reactive otherwise is going to get consumed inside the, otherwise is going to get consumed because of some reaction and if it gets consumed then one cannot observe the non-ideal behavior or non-ideal flow pattern using this particular tracer and then it must be easily deductible. So the tracer chemical must be easily deductible that means that there must be methodologies well established methodologies in order to measure the concentration of the tracers in a very short time which means that the equipments must be sensitive enough to distinguish the small concentrations of the tracers. The physical properties should be such that similar to that of the reacting mixtures. So if the physical properties are not similar then it does not reflect the exact flow behavior of the reacting mixture which is of interest to actually study. So now in addition to that it must also be completely soluble, it must be completely soluble in the reacting mixture and it actually should not absorb to wall or any other surface of the reactor. So it should not absorb to wall or any other surface because if it gets absorbed then the sum of the species are being consumed and that is not going to help in actually measuring the residence time distribution of the reactor. So typically colored and radioactive materials along with inert gas are actually commonly used as tracers. So inert gas with some colored and radioactive material. So these are all commonly used tracers for actually finding the residence time distribution. So there are actually two common strategies for injecting the tracer. So two strategies for methods. So there are two methods for injecting the tracer in order to study the residence time distribution. The first one is the pulse input and the second one is the step input. So these are the two classical methods of tracer injection in order to detect the residence time distribution. So which is what we will see in the next lecture and what we have seen today is basically to introduce what is the non-ideal behavior and that to appreciate that the real world reactors do not behave like the ideal reactors such as the plug flow and the mixed flow reactors that we have studied in the in the past. And what are the definitions that is the residence time distribution definitions that are actually involved to characterize such kind of non-ideal behavior. So what we will see in the next lecture is to look at what is this pulse input and the step input method in order to track the residence time distribution of a given system. Thank you.


In this video, we will show you how to create datasets within DHIS2. We will create the RMN-CAH dataset using the metadata we have already configured earlier in this course. The first step is to create a default dataset where we can figure the basic information about the dataset, including entering its name, selecting the period of collection, adding the data elements associated with the dataset, and assigning it to the organization units for which data will be entered. The second step is to create the sections. For each section we create, we need to define a section heading and assign the data elements to the section in the order we want them to appear within the data entry form. Let's see how it works in DHIS2. To create the new dataset, open the maintenance app. Next, select the dataset tab and choose dataset from the left menu. This will open the dataset maintenance page, where you will see a list of the data elements created in the system. The datasets that you see here are dependent on your access within the system. Since this is a new database, we do not see any datasets. Look on the plus icon to begin creating the new dataset. Start by filling in the name. In this example, we will use rmncah. The next required field is the period type. The period type defines how often these data are collected and entered into DHIS2. In our case, we will select the period type monthly. Notice the field above the period type is the days after period to qualify for timely submission. The default setting for this field is 15. This means that the dataset must be submitted within 15 days after the entry period has ended to qualify for a timely submission. In this example using monthly periods, it means we have to complete the data entry on the dataset by the 15th of the next month for it to be classified as a timely submission. This can be changed to a different number of days depending on the specifics of your program. Category combination is the next mandatory field. For our example, we will leave it as none. For more information on category combinations as they relate to datasets, consult the DHIS2 documentation. Now scroll down to the data elements section to add the data elements to the dataset. All of the data elements in the available list are ones we want to assign to the dataset. Click on assign all to move them all to the selected box. The final step is to assign the dataset to organization units. This determines where the data will be captured. In our example, we need to select all facility level organization units. Organization units can be selected in multiple ways by opening the hierarchy and selecting particular units by using the organization unit level field and selecting all organization units at a particular level or by using the organization unit group field to select all organization units within selected groups. For our example, use the levels option and select facility level organization units. Then click on select to select them in the hierarchy. Notice the facility level organization units are now listed in orange as they are selected for the dataset. To save the dataset as a default form, click save. To wrap up, the steps to create a dataset as a default form in DJI's 2 are, open the maintenance app, select the dataset tab and select dataset from the left side menu, then click the plus sign to create a dataset. When open, define the key fields, name and period type. Add the data elements to the dataset and assign the dataset to organization units. We will learn how to change the form type from a default form to a section form in the next video.


We've had the development of an American film culture and American film narrative, you know, that has been very kind of very Western specific because hardly anyone else was allowed to participate in the creation of narrative and the creation of films besides white men, even until today. An issue in our American media culture is the absolute invisibility of native people in American media, you know, lack of representation and invisibility, not only in education, but in popular culture that also can impact the public policy process regarding health, education, welfare, resource management, every issue that tribal governments deal with on a daily basis that are connected to federal government decisions. I think a great opportunity for impact I think just on the American public would be for the average American to understand that there were and are people here who are indigenous to this land and no matter where you go in the United States it's indigenous land. Everyone might not be open to it, but I think that some type of empathy would really be great, I think, towards the native experience and the fact that native people exist today, you know, and I think a great impact idea is to just really try to figure out how to uplift this idea of native representation, you know, within our education system and within our media culture. As native people, we just we want to have a narrative in media, you know, because of the invisibility factor, we don't have one.


We have developed a new special explicit map of pit location, extent and depth for the tropics. We see a bias in our understanding of where current tropical are located towards Southeast Asian Indonesian. What the map is suggesting is that there is much more tropical pit located in Africa and in South America, in particular Brazil, being the host of the larger amounts of pit. The degradation that IPCC is taking? Yes, it's interesting development now. Countries already submitted their nationally determined contribution, NDC, and some countries already included pit in it, but some do not because they do not know exactly what's the role of this particular ecosystem they have. So in the next round of the NDC, I think it's important to consider including pit land. Carbon stocks of pit lands? I do think the livelihood issue is central, and I think we need to make sure that in the climate change convention, we need to make sure the people focus on that and keep that in the focus. It's not just about carbon. When we talk about pit lands, everybody focuses on the carbon just because the emissions are really so high. But we have to remember people living in these landscapes, they need to be able to meet their economic needs, they need to be able to provide for their children and their families. So if we bring this all together, I think we can find rational solutions.


This is my co-speaker Karan Rudeja. He is a UX designer from Global. Hi everybody. We would like you to please put your phones on silent. That is, don't switch them off. Just put them on silent and sit back, enjoy and we hope you like this sensorial ride. So, if you have anything in your hands by any chance, just keep it aside for a second. Yeah, release your hands and then just sit back, calm yourself down, settle down.  Breathe out. Hear my voice. Hear the sounds inside the room. Feel your hands. Join your hands. Breathe in. Breathe out. Thanks a lot. Now you can open your eyes. Now you will find this little peanut or groundnut that may have been given to you.  So, this small little daily object that we find called the groundnut or the peanut. Hindi may they call it Moon Pali. It's very interesting because it's got color, texture, it's got this certain form. You can peel it in your hand and you open it up. It's got this sound and you can smell it and of course eat it. So, basically this small little object is in a way reaching out to all your senses. Next thing, what we have is a small sense test that we'll try to do with you. What we are going to do is that I'll show you a small video. A syllable is going to get repeated. Then I'm going to ask you what you're hearing and you can tell me about the show of your hands. This is the part where it goes like ba, ba, ba, ba. So, what are you actually hearing? It's the first or the second one. It's the first or the second one, can you please? Right. The next one, ba, ba, ba, ba. Was it the first or the second one? I'll do the first one again. I'll try. I hope I can do it as well as this guy did.  Ba, ba, ba, ba. Open your eyes. What were you hearing? So, that's what happens.  And what happens is that when the brain is competing for both these information, it wants to make sense of what is happening in the environment and it immediately jumps to conclusions. So, you think that I'm saying ba, but actually I was saying ba. It's the same syllable. This effect is called the McGurk effect. So, we have another small thing that we can try. So, you will find a small candy on your seat or next to your seat. So, if you can just please open it and so, this might be a bit uncomfortable. So, what you need to do is you need to close your nose and without breathing chew the candy for like a few seconds and then open your nose. So, you might feel that once you open your nose, there is a difference in the sense of flavor that you have. So, what happens is that what we often think of as taste is a combination of what we actually taste and what we smell. So, these two little things are just to illustrate the point that as children we are taught that we have five senses and they have their own individual functions. But actually the perceptions that we have are actually made of multiple senses. So, what do you see affects what you hear also. So, this is. Next thing is a short story that I'll tell you which is which happened recently in my family and that was the moment when I got this realization that you know the senses are actually quite important to us and they affect you know decision making. My dad wanted to buy a dining table and he had this thing in mind like you see in hotels which have a stone top and he was really crazy about it running after it and one day all of us went to the mall, he found the dining table, he was very excited, he almost bounced on it, sat down and few minutes later he comes to me and tells me that I like the dining table, but I'm not going to buy it and I asked him why. He said that when I sat on it and I kept my hands on it, my forearm fell cold so I don't want to buy it and that was the moment where I realized that you know the sense of touch and the temperature was something that completely entirely changes the decision of going for that table and that's when I felt that you know these senses are a lot more important and we shouldn't probably take them for granted.  Suppose these are the caveman children, we can probably call them boogers for now and their senses were very like you know good and proficient in comparison to us because they're survival dependent on these senses and because they would get like you know attacked by predators and all so they would always have to be on high alert and that's where these senses help them. Moving like fast forwarding in time, we have the zone act. The zone act are the people like us, the civilized kind so ones who are living in these urban artificially designed environments we don't have threats from predators, nobody's coming and attacking us and that's why we may have seen that you know our dependency on the various senses has kind of gone down which I'll elaborate through this graph. This is called the bandwidth of senses which is showing us that we are heavily dependent on sight, then touch, hearing, smell and finally taste. This is also showing the amount of information that your brain is getting at any particular second where sight being the maximum followed by the other senses and with this we can see that you know since this study was done on people like us like zone act we can in a way infer that because of this dependency and the way the biological evolution is happening the way design is also proceeding is also changing which is why we have seen this heavy reliance on screen and interaction design seems to be chasing screens for some reason. So for last I think few months like 6 months or 8 months we have been like exploring this domain of alternate senses and so we came across this interesting way of analyzing our daily interactions in terms of what senses they are catering to. So if you go to the next slide so this is the graph of cooking so you can see that cooking as an act involves all the senses so there is like sight, touch, smell whereas if you look at something like driving so it's heavily dependent on sight and sound so maybe on touch. So piggy bank is something very interesting where it's not really dependent on sight as such but you can sort of pick it up and feel the weight of the piggy bank or shake it and hear the sound and that sound and the weight informs you of the contents inside and the quantity inside then if you look at any of the mobile applications so most of them are obviously dependent on sight and maybe slightly on sound Just one last thing I want to add here is that so using this graph you can actually see whatever you are designing what all senses does it map to. Now designing for the other senses Yeah so for this we have a couple of interesting examples that illustrate how we can design with other senses So this is one of the projects that cater to majorly to the sense of taste This is a project that we both worked on along with two other people Okay we are super sorry the video isn't playing because of some technical glitch you can talk about. Okay so what this project does is that so right now we are creating a lot of digital information through our fitness bands and our mobile applications and every transaction that we do on payment portals So we are thinking about how this data can be experienced by people not just through numbers or through emails but through some other senses. So this is a project called Data Jelly we bought where it is a bought which asks you a certain information about you let's say you are attending a conference so it asks you certain questions like what are you here for what do you do like are you a designer are you an engineer these kinds of things and it takes that information and converts it into an abstract form which is then printed in the form of a jellybee which is an edible Indian sweet that is actually like then fried and dipped in sugar syrup and then you end up consuming it. So the idea is to in a way in an abstract form consume the data through taste through smell through touch and not just through sight I would have really enjoyed all of you seeing this video because that's where you actually get the sense of the project and if you actually want to see it happening in real please come to design up that's where we are showcasing on the 10th and 11th of November this project was initially showcased at Interact 2017 it was a recent HCI conference in Mumbai and this is Hitachi they are using Hitachi project yes we have you can also check out the website datajellybee.com meanwhile we have in the experiment that we are trying to investigate alternative ways of data consumption but up till now we have solved about 300 plus people it has been a fun journey because people come provide their data can be their professional profile the project was trying to capture the interaction pattern that people have when they come to conferences and they have a simple conversation and they would exchange like it's a small talk that happens so I'd probably come and say hi to Karan Gideja and I work as a UX designer out here and this is like I've worked for about two and a half years or something my interest career there so and so forth and I'm your other presenter or the visitor so she gets a certain idea of who I am and in this project DataJellybee what we've done the same thing where this entire profile gets captured and then it is in a way represented using a visualization which is borrowing the aesthetic from the patterns of rangoli and mandala which are in a way integrated to the Indian culture DataJellybee what this is the graph that would happen for like you can see that it since it's a food related project it will be equally high on parameters for all the sensors next project that I will show you is Sonic Bells which in which the person has a small weight and they're trying to show that there is a couple of activities that we do on a daily life they're taking the example of exercising where so you will see the activities that she's doing and the sounds that are being created by the phone they allow her and the group to understand so for this project this would be the mapping where size and touch are heavy and so is sound this is a project where people have taken this idea that whenever gas leaks happen and people can't see it they would induce little bit of an artificial smell inside so that people know that there is some sort of a threat or a danger and they've taken the same context and applied it to how we have our computers connected to the net and we are in a way potentially possibly it can get attacked by a threat or virus attack so this small device whenever it senses that you are getting attacked it releases fragrance and cryoscope this is the final project where what it does is that there is a small aluminum box and it is connected to the... the cryoscope is a haptic weather forecasted device it consists of an aluminum cube which is heated or cooled as far as forecasted temperature the users enter their location into a web app the cube then automatically adjusts to the forecasted temperature again it would be very high on touch and now you want to know why are we advocating this entire thing of designing for the sensors because we feel that as you saw in the previous framework of the graph that once your sensors are being mapped through the project they are a lot more engaging, a lot more emotional and a lot more experiential. So now the part about how actually we can go about doing this. So you might say that okay this is interesting but if we are to design with other sensors how can we do that so now the thing is we have spent a lot of time understanding how the sense of sight works and a lot of psychology and cognitive psychology has done research on that but we have to understand that the other sensors are fundamentally different from how sight works so if you are to design for them there will be certain different things that we should keep in mind and also one of the good things is that the other sensors allow us a certain key advantages that sight does not have. For example the other sensors like unlike sight where we are only seeing what is in front of our eyes something like smile or something like sound is something that we always hear wherever it's coming from. So we can actually utilize something like that nature of the senses and communicate information through less smell while you are already engaged on a screen so you can have to break your flow to complete that new information that is coming to you. Then the second thing is that this is in a way a limitation because our sensors sight is so tuned to understanding so much information but the other sensors are not that trained in accessing information so we have to keep in mind that if you are trying to communicate something through less smell it should be very simple something like binary states of right versus wrong or success versus failure or so for example something like success of a payment process or success of order can be communicated through a pleasant smell whereas failure can be communicated through unpleasant smell which is something that is happening in the background in a slightly abstract manner. Then the third thing is that as we saw in the beginning that all our perceptions are actually made of multiple senses so we can also think of designing for screens where there is maybe like one or two additional senses which are complimenting what is happening on the screen. And the fourth thing is mapping so although current will now turn on the Bluetooth speaker and now we will turn it off so you can see like certain even without knowing anything about the speaker you can know or you can detect which one is the turning on sound and which one is turning off because it is catering to certain basic human understanding of right we can fall in the pitch of the voice or the sound. So what are we mindful of these associations that we have for example smell is something that is very subjective so you have to be aware of these associations and design in sync with that. We will skip the ideas because we are short on time. We hope for some of this as a primer to designing for the other senses made sense to all of you. Thanks a lot for your attention I am Karan and this is Gaurav. We are host graduates from Media Design NID. Hope you have a nice day and enjoy the sessions to you. Thank you so much.


This is Think Tech Hawaii, Raising Public Awareness. Aloha, I'm Kaui Lucas, host of Hawaii is My Mainland. Think Tech is important to our community because instead of the usual 30-second soundbite, we have enough time to have the discussions to come up with real solutions. And for the first time, Think Tech Hawaii is participating in an online web-based fundraising campaign to raise $40,000. If thanks to Think Tech will run only during the month of November, and you can help, please donate what you can so that Think Tech Hawaii can continue to raise public awareness and promote civic engagement through free programming like mine. I've already made my donation and look forward to yours. Please send in your tax-deductible contribution by going to this website. Thanks for thinktech.causevox.com. On behalf of the community enriched by Think Tech Hawaii's 30-plus weekly shows, mahalo.


Poly, anisopropylacrylamide, PNIPAM, hydrogels are being increasingly used in biomedical applications due to their unique properties such as temperature-sensitive swelling behavior, tunable mechanical properties, and high water content. These properties can be further enhanced by incorporating other polymers such as poly, ethylene glycol, PEG, and or poly, epsilon caprolactone, PCL. Additionally, biopolymers such as collagen and hyaluronic acid can also be used to improve the biocompatibility of these hydrogels. Furthermore, advancements in three-dimensional bioprinting technology will enable the development of novel medical devices and tools with temperature responsive properties. This article was authored by Sonia Lanzalaco and Delayne Armelen.


Hello and welcome to a lecture on distance vector routing. Learning outcomes by the end of the session student will be able to illustrate distance vector routing algorithm. Here you may pause the video and answer this question. What do you mean by adaptive routing algorithm? Adaptive routing algorithm modify their routing decisions or the routing tables to accommodate the changes in the network topology and changes in the traffic as well and these adaptive algorithms are also called as dynamic routing algorithms. The distance vector routing is a adaptive routing algorithm means it accommodate the changes going on in the topology of the network and changes going on in the traffic as well. An autonomous system is seen as a graph with nodes representing the routers and the arcs or the line connecting the nodes represent the link. The distance vector routing is based on a graph theory. This graph theory uses an algorithm called as Bellman Ford or also called as Ford Fulkerson algorithm which find out the shortest path between the nodes in a given graph provided the distance between the node is given. The basis of this algorithm is very simple. If all the neighbors of the node i knows the shortest distance to node j then the shortest distance between node i and j can be calculated by adding the distance to node i and each neighbor to the neighbor's shortest distance to the node j and then selecting the minimum among all. In distance vector routing algorithm each router maintain a routing table and that table contains the best known distance to each destination network and which output line to be used to forward the packet so that it reach the destination network. These routing tables are updated by exchanging information with the neighbors. The router is assumed to know the distance to each of its neighbor. The distance is nothing but a metric. The well-known metric for distance vector routing is number of hops. The distance to the adjacent node when the metric is hop is just one hop. The other metrics are also possible like bandwidth, traffic, cost, communication cost and so on but generally for distance vector routing the metric used is hops. Distance vector routing uses Bellman-Ford algorithm and what is that let's see. In Bellman-Ford algorithm the cost normally used is number of hops so the cost between or the distance between any two directly connected routers or the network is set to one. Each router needs to update its routing table independently whenever it receives some information from its neighbor. Once a router has updated its routing table it should advertise the results, updated results to its neighbor so that the neighbors also can update their routing tables. Each router should maintain at least three pieces of information for each route entry and the first piece of information to be maintained is destination network, the cost to that destination network and the next hop to reach that destination network. The update advertise has only two pieces of information in it. The destination network and the cost for each route is advertised. Advertise means it is sent to the neighbors. The next hop information is not included in the advertised message because the next hop is nothing but source address of the sender itself. Then how the routing tables are updated. Whenever a update reaches a router the router searches its routing table for the destination network received in the advertisement. Then there are the two chances if the corresponding entry for that particular received destination network is found then there are two cases. The first is if the cost to the advertised network plus one is smaller than the corresponding cost in the routing table which is already present. Then this implies that the neighbor has found a better route to the destination network. Then the second case is if the next hop is same as that one in the previous table it means some change has took place in the some part of the network. If the destination network received in advertise is not present in the routing table of the router then the router add this entry to its table and sort the table according to the destination network address. Let us see how distance vector routing updates the table with simple example. Here we have one autonomous system as distance vector routing is an interior protocol which handles the routing inside this particular autonomous system. This autonomous system has 5 routers router A, router B, router C, D and E. Each router has their routing table which is prepared or filled with some entries upon booting without any updates. It is on booting the routing tables have the entries of their directly connected networks. Now let us understand how the after receiving updates how the routing table is updated. Consider that router A sends 4 updates 4 update advertise or updates to router B ok. Then here you can clearly see that here these 4 updates are sent to B from router A ok. Then when the first update reaches the router B then router B search for the network destination network here the destination network is net 1. Search for this address in its routing table and as it does not have the entry for the net 1 he will add that entry and as router B does not have the entry for net 1 he will straight away add this entry to its routing table with increasing the cost by 1. The received cost or the distance is 1 so he will add to that another distance 1 and it becomes 2. Then in the next hop entry column he will add the address of the advertiser the advertiser is nothing but A so in this column the entry will be router A. Then when it receives the second update then he will check his new updated routing table whether the net 2 this destination net 2 is present yes it is present and the advertised cost as it is equal to an already cost which is present in the routing table he will not update or he will not add this entry to the routing table. Here is your second table which shows that it has already net 2 when he receives the third routing update that time he will check whether net 4 is present as it is not present in its routing table he will add that entry by increasing the distance or the cost by 1 and next hop as A similarly after fourth update he will add the net 5 network 5 with cost of 2 and next hop as a router A. All the 4 updates are now accommodated but the routing table of B is not yet complete because B does not have any idea about this network 7 ok so some more updates are required similarly you can construct the routing tables of all the routers these are the references used and thank you.