Mod-01 Lec-5 What is Chemical Reaction Engg. Part I

So, now the next question is: What is chemical reaction engineering? Chemical reaction engineering, okay, we will abbreviate it. This is a wonderful question. Do you have a definition for this? What is chemical reaction engineering? That is the question. Well, some of these concepts we understand, but we often struggle to explain them clearly. It's similar to legal terminology. Chemical reaction engineering isn’t so bad, but the definition itself—the title "chemical reaction engineering"—provides a good insight. Essentially, you are engineering the chemical reactions, and that is a solid definition.

But again, unless you know what you mean by engineering, you cannot explain further. I don’t know if some of you have noticed, but there are many new books coming out in the field of chemical reaction engineering. One of the books, which I believe is by Schmidt (spelled S-C-H-M-I-D-T), is titled "Engineering of Chemical Reactions." Have you seen that book? What do you think of its title?

Yeah, excellent. Data engineering is the engineering of chemical reactions, and that is truly what it means. I really appreciate the name itself. Do you know who suggested that name? In fact, it is one of the latest terms in chemical engineering.

By the way, who suggested the name "unit operations"? It was Arthur D. D. Little, and I think you should take note of that. After giving the definition, Little has become quite significant in the field. However, before him, there was another person named G. A. Davis. You may not know this, but how did you come across the name? Perhaps you searched for it and found it from us. Actually, the idea originated from Davis, who was based in the UK during the 1860s and 70s. He worked as a factory inspector.

Actually, he was the first person to teach a course in chemical engineering. That was, I think, in 1895 or 1897. At that time, when he was a factory inspector, there was a significant amount of pollution, particularly from sulfuric acid and chloralkali industries. A lot of chlorine was being released, and there were high levels of sulfur dioxide as well. This is why the UK government appointed him as a factory inspector. His job was to visit these factories and investigate the issues. During his visits to various industries, he noticed something common among them: fluid flow was present in every industry he examined, as well as heat exchange processes.

That means different forms of condensation are a kind of heat exchange, as well as normal heat exchangers. There are all kinds of heat exchange equipment, and you also saw distillation columns. However, without knowing the names, they were still performing distillation. They understood the process, but the unit operations nomenclature was not available at that time. He recorded all of that. Before this, chemical engineering was taught by discussing industries. For instance, in pure chemical technology, you would take a specific industry, like the chlor-alkali industry, and then discuss various chemicals, their production methods, temperatures, and pressures. At that time, applied chemistry departments didn't have chemical engineering programs. I am referring to the 1870s, 1880s, and 1890s.

So, he mentioned that there are many common operations, listing them as part of a course that included about 12 lectures. I want to access the original lectures, but I'm unable to do so. He explained that instead of focusing on a particular industry or chemical, he would discuss general operations, such as fluid flow. The topic of materials of construction was taken very seriously during our B.Tech program. We had one or two courses on materials of construction, and I believe you had Ranganathan as well. However, that has since changed, and I'm unsure if you've taken any courses on materials of construction or plant utilities. Some universities, particularly older ones, still offer courses on plant utilities. As a result of this knowledge, we learned that similar teaching methods were being employed in the UK. Arthur D. Little discovered this and decided to give it a name: "unit operations." What a wonderful name!

So, now under unit operations, you have distillation, extraction, and crystallization. I mean, of course, heat transfer and all these operations will come into play. Then, beautifully, McCabe and Smith used that title: "Unit Operations in Chemical Engineering," which is the title of their book. Similarly, in 1957, which was quite late—chemical engineering was already somewhat established by then—chemical reaction engineering had not yet been fully recognized. In 1957, there was a conference in the Netherlands, where the title of the conference was "Chemical Reaction Engineering," and they wanted to focus specifically on reactions.

And they wanted to concentrate only on reactions. In a unit operation, all the focus is on separation or mass transfer, heat transfer, and that kind of thing. There is no chemical change, only physical change. That is why all unit operations deal with physical changes. Then they wanted to know if a separate course on reactions could also be offered. Until then, reactions had not been taken very seriously.

They do not know how to determine the kinetics, but approximately they understand that this is related to temperature and pressure. That is why applied chemists engage in exploratory research, which I mentioned earlier is based on trial and error. Through this method, they learn that a particular reaction will occur at a certain temperature and pressure, and what type of equipment can be used. All of that has been established, but it was not classified as science or even engineering. I will also clarify the difference between science and engineering. At that time, the person who named this field was J.C. Vlugter. In Europe, the "v" is pronounced like "f," so it is referred to as "Fluchter." Yes, J.C. Fluchter Vlugter. He was the one who provided this name for chemical reaction engineering for that conference. They wanted to discuss it at the conference, as Gani mentioned, and Abduljab was explaining how the reactors work.

What information is required for reactors? All the proceedings from the first conference were published in the 1958 edition of *Chemical Engineering Science*. In 1958, there were several issues published; I believe there were about six issues or so. I should clarify that I am not only speaking in English. There is a journal called *Chemical Engineering Science* that I think started in 1953, which would be the first volume, correct?

Volume 51 and 53 are the second and third volumes, respectively. The Chemical Engineering Science journal began in 1951. For the 1958 volume, we compile all the issues from that year into one volume. This means that all the papers published or discussed at the conference are included in this volume, which is available in our library. It is also accessible online; simply go to Science Direct, navigate to Chemical Engineering Science, and look for the 1958 volume. I believe it may be the June or July edition, but I'm not entirely sure. You can verify this information.

So, he has given that name—a wonderful name. You are engineering chemical reactions. What do you mean by engineering chemical reactions? To understand this, you should know the difference between engineering and technology. These are words we frequently use without knowing their meanings. I will tell you something interesting. When you want to pursue engineering, you have to write an entrance exam. It could be JEE (Joint Entrance Examination) or other state-level exams. Each state has its own set of exams, such as KEAM for Kerala, EAMCET for Andhra Pradesh, and TS EAMCET for Telangana. All these are different examinations for admissions. So, what subjects do you need to choose for that examination if you want to become an engineer? Math, physics, chemistry, right?

So, once you pass or achieve a good rank in the entrance examination, where do you go for engineering? You enroll in an engineering program, right? In the end, what degree do you receive? You might read "Bachelor of Technology," but have you ever thought about the connection? This year, we have only taken the entrance examination in subjects like math, physics, and chemistry. Then someone tells you to join chemical engineering, mechanical engineering, or civil engineering. Ultimately, we all end up with a Bachelor of Technology, but where is the connection? Do you know the connection? Even after completing an M.Tech, do you know the connection? Forget about B.Tech; have you ever pondered those fundamental questions? I think it's important to question this yourself: Why am I here? Why was I born to these particular parents? Some people seem very happy, living in beautiful houses, not having to do anything aside from taking over their father's business, and already being rich. They might not even know where to keep their money; they can sleep on currency, eat currency, and live in luxury. All those beautiful things are great, but unfortunately, we may not have that choice; however, we are happy with who we are. These are the kinds of basic questions I think we should all consider. I don't know if any of you have thought about them, but if you have, please raise your hand. That would be very good.

You thought about that? What is it—what time is it now or earlier? Before. Before? Okay. Yeah, that is very good; that kind of thinking is required, right? Then what is the difference anyone has been exposed to? What is the connection, or what is the definition of science, engineering, and technology?

Some teachers would have told you that people like me think there are individuals who can communicate effectively, and that is important. I'm not quoting anyone specifically, but I believe an excellent teacher not only teaches the subject but also provides an approach to it. If you want to understand that approach to a particular subject, you need a strong foundation; otherwise, you'll never grasp the concept. I could have completed 50 percent of the syllabus in the last two weeks if I had started with first-order reactions right away. However, I believe you need this kind of background knowledge—these conceptual seeds in your mind. It's mind-clearing. Before you can absorb new information, you must eliminate any irrelevant data; it's like cleaning your mental hard disk. That's what I'm trying to do now. I want to clear my mental hard disk so that only chemical engineering knowledge remains. One of the definitions given is that the application of science is engineering, and the application of engineering is technology. However, if I ask you to explain that definition again, you might struggle to do so, right?

Yes, should I write that the application of science is, in fact, a small abbreviation of engineering, and the application of engineering is technology? In essence, technology is the highest form. However, unfortunately, you can become a technologist without knowing any engineering or science. Nevertheless, we have been doing this for a long time. The human race has constructed beautiful forts, houses, temples, churches, and mosques. I believe they have done this wonderfully, even without having a civil engineering degree.

So, they are the people who are knowledgeable in technology. How do they know? Feel. We also recognize the practice of medicine in villages. Of course, we think of villages as places where there are doctors who possess certain knowledge. However, at that time, there were no MBBS or MS degrees, yet they had developed that kind of expertise. Now, let me explain how to produce bricks. Before we get to bricks, let's talk about how to make curd at home. Your mother knows this process very well. What does she do? Initially, she doesn't just take the curd and put it somewhere. The first step is not simply taking the curd and placing it somewhere.

Boiling. In the mouth or somewhere. Yeah, the first thing is to find out where the milk is. Take the milk and boil it. Who should you boil?

Pasteurization. Everything is a question. Who should you boil? Pasteurization. Pasteurization.

What is pasteurization? Pasteurization is the process of heating a liquid to kill harmful microorganisms without destroying the beneficial ones. This is why we boil the liquid first. After boiling, it becomes clear that some microorganisms, like weasels in the kitchen, are always present. The first weasels, the second weasels, and third weasels keep coming back, likely due to the use of pressure cookers and other cooking methods. Essentially, cooking is all about managing these microorganisms.

So anyway, I think you know she knows when she has to stop that boiling. Then what will she do? She will add cold water. Anyway, I think you know she knows when she has to stop that boiling, and then what will she do? She will add it to cool it down. Cool it down.

Cool it. Cool it. Why can't you eat immediately? Because microorganisms will die. They cannot withstand heat, much like being placed in a furnace at 100 degrees Celsius; that would be the end for them. Similarly, when you boil something and then immediately introduce microorganisms, they will die.

So, that is why she cools it; it is not a sudden cooling. She will not use brine at minus 5 degrees and then suddenly cool it; she will wait patiently. Every time she goes to touch the surface of that container, she knows the right temperature. At that time, she adds yesterday's curd or yesterday's buttermilk, where there are microorganisms. Then her duty is over; it is now the microorganisms' duty. After maybe 6, 7, or 8 hours, you will have beautiful curd. You know how to eat curd, but I think about how much technology is involved in this process. Without having any degree or knowledge of biochemistry, mothers still manage to do it.

She does not know what heat transfer is, yet she knows how to boil milk properly. She doesn't measure the temperature; in fact, she never measures it at all. However, she is aware that when the milk starts to froth, it is close to boiling. Once or twice, she will notice the foam rising and will then switch off the heat and wait for a moment. While she may occasionally try to speak during this process, it's not necessary for liquids. Some people may stir the milk while waiting, but she doesn't feel the need to do that.

So, actually, my mother is an excellent technologist. Without knowing anything, she can cook food that you can enjoy for a lifetime. As I mentioned last time, mother's food is something you can eat forever. But if you go to Tiffany's, after two days, at most, you will feel like saying, "Go to hell; let's go to some other house or some other place." You can see the appreciation for the mother in that. That is the kind of technology she has developed. Now, a technologist is someone who knows how to make things by finding the right conditions, which could be temperature, pressure, etc. I am talking about our chemical technologies. We have various chemical technologies, for example, fertilizer technology, rubber technology, polymer technology, and cement technology. All these advancements have been made even before the emergence of chemical engineering. How did they manage to do this?

By trial and error. They may have spent 50 years, 60 years, or even 70 years coming to those points. After stabilizing for those conditions, the transfer of knowledge becomes very easy. You train one person to maintain these conditions, and then the next person comes along to train others. This is how it continues. This is what we often consider to be the most basic technology, but that is not correct. For instance, how do they make bricks?

Because most of you were born in cities, you may not know how brick kilns are made. However, if you visit rural areas or the suburbs of cities, you will see many brick kilns. They use mud, but not just any mud; they select a specific type that contains sand and clay with a certain percentage of solid content, which is very important. They do not measure this precisely, but from experience, they can tell by the feel of the mud in their hands whether it will produce good or bad bricks. After selecting the right mud, they add a sufficient amount of water to create a paste. Most of the time, they use their legs to mix the mud and water together. This method is part of their traditional technology. The mixtures they create are based on experience, and they instinctively know how to achieve the right consistency.

That is the technology. Actually, these are the mixtures. Correct. Not like this, like this, like this, like this—you do it all the time. Then they mix it; they know the right consistency. They would not put in more water, nor would they put in less water. Less water is also difficult, and more water is also not the right amount. Then they take the molds; you know, big molds.

Then they just paste it, pour it, level it, and then remove it. However, leveling is not something that all of us can do. They know how much pressure they have to correctly apply to that mold on the surface of the mold. Otherwise, you will not get the right brick again, and the strength will not be there. After that, you need to dry the bricks; you know, natural drying, or solar drying. Right after solar drying, if you use the bricks and then it rains, they will dissolve.

So, that is why they have to sinter it; sintering is done in a kiln. Then, you will have the strength you know—the bond between all those particles, all that mud becomes very, very strong. But where is engineering, and where is technology? Various signs are displayed here. When a mother makes curd, what signs is she using? What engineering is she implementing? Now, I will ask a question: when a mother makes curd, what is the scale of her production? Typically, it’s a maximum of one liter. If some guests come, maybe she can go up to three or four liters. Now, ask her to try producing 100 liters—it's impossible; she would run away.

That is where chemistry stops; I told you that engineering starts. Yeah, I mean, it's not exactly chemistry there, I'm telling you. That is where scale-up comes into play because now we are talking about large scale. We have 7,400 students in the hostel – not even 8,000, I think it's about 7,400 students. Now, we want to make curd for 7,400 students.

How do you make it? As a chemical engineer, what do you do? You know that every student may use about 300 ml of curd, which is quite a lot. I think 100 ml of curd is sufficient. Many North Indians might not use curd, but for South Indians, curd is the main point; they only stop eating after they have had curd, continuing to eat until then, either curd or buttermilk. Recently, I went on a tour to Leh and Ladakh, and I noticed that in North India, people from Delhi onwards start their mornings with curd.

Many people you know enjoy aloo paratha. When we ask them how they eat it, they mention that they serve it with achar. I didn't know what achar was.

Achar was pickles. Yeah, I mean it is mouthwatering. It is good and very tasty. So, this achar with curd—it has a wonderful taste, I tell you. It's a very good taste; I liked it. Unfortunately, we cannot make that kind of beautiful aloo paratha on this side.

But the problem is that I can guarantee that health will be compromised in 2 to 3 years. So, if you eat this every day, it's concerning because achar is very bad due to the tons and tons of salt. Salt is always detrimental to health, and of course, they also use a lot of oil to make aloo paratha. Regarding curd, I think it's actually unnecessary for human beings. I have a separate theory on this, and when I have time, we can discuss that particular topic. Anyway, the curd is a large portion; do you realize it's 100 ml per serving? Considering there are approximately 7,000 to 8,000 students, you can calculate how much milk you need to boil for that many servings.

How do you boil? First of all, you need a large vessel. You also have to decide whether you want continuous boiling or continuous cooking. I remember thinking about a continuous rice cooker about 15-20 years ago. This would mean you could feed rice into one end and have cooked food come out the other end. However, it turns out that this is not an easy process. Why is that?

Because I have to maintain a very clear plug flow, I will discuss what plug flow is later. That is why ether can be used in a system or batch system. Most of the time, in all cooking, you opt for batch cooking. It is a wonderful concept; without knowing what plug flow is, people utilize batch cooking. In batch cooking, every particle stays in the system for exactly the same amount of time. For example, if you specify a cooking time of 10 minutes, all the particles will be in the system for those 10 minutes, resulting in uniform cooking.

If you allow them to flow, there may be small particles that come out faster, and there may also be larger particles. You know, uniform rice is hardly ever achieved. I think nowadays basmati rice can be almost one inch long. I'm not sure how you would put that in. When it flows, the shape factor is very poor; the fluid mechanics suggest that it will not have a nice flow for this kind of particle. Anyway, whether you choose batch or continuous processing, you cannot simply boil it because there is a large amount of milk in the vessel. When you boil it, which portion or part of the vessel will receive the heat first?

The bottom and sides of the pot are also important, especially if it is made of metal. When you are boiling milk, the top layer of liquid does not receive sufficient heat. If you continuously boil it, the milk near the surface can spoil and become charred. This is why stirring is necessary.

Then only will you achieve uniform heat for all the milk. Now, that is an engineering principle. How you supply heat to this vessel is also an engineering principle. All of these considerations weren't present when mother was doing it. She knows how beautifully it can be done and what kind of vessel she needs to use.

Normally, we never use a mud vessel for boiling water or milk. There are mud vessels available, but we never use them. Do you? We only use metal because heat transfer is better with metal. You see, all these things that people do not understand, yet they still follow these practices—that is what being a technologist is about. Now, consider how engineering automatically comes into play when you're thinking on a large scale. So, what is engineering? You need to learn what it truly is.

So, now what is engineering? First, you have to learn about heat transfer: how do you supply this heat, and what equations are required. If you want to raise the temperature from room temperature to 100 degrees Celsius, or maybe 80 degrees Celsius for milk, you need to calculate how much heat is required. All of these calculations are based on engineering principles. Next, consider the stirring process. What kind of stirring is required, and how do you achieve this? You can use people to stir manually or implement a motor connected to an electrical supply. All of this needs to be discussed. When you want to design an actual mechanical stirrer, you will again need that information. That is why you have to delve deeply into topics like mechanical operations and fluid mechanics. You will learn about agitation and mixing—there is indeed a chapter on that, isn’t there?

Yeah, so all of that is what engineering is. Now that we know what technology and engineering are, it means that engineering cannot be described simply in terms of words. When it comes to engineering, you need to use equations to calculate or find something. For example, I can tell you that it takes approximately 67 hours for curd to finally set.

Now you want to make instant curd. You don't have the patience to wait. In 10 minutes, you should have curd. What do you do? What is responsible for curd making?

Converting milk into...? Is it a chemical operation or a physical operation? Very good, it is a chemical operation. Why? Because the starting material and the final material have different properties. That is why we can classify this as a type of chemical reaction. So, what was the question I was asking?

How quickly can you increase the rate of a reaction? Earlier, it took 8 hours. Now you want it to take only 10 minutes. What do you do? One option is to find a catalyst, but a catalyst for what? Where do you apply this catalyst? We know that microorganisms are responsible for the conversion, so should you add the catalyst to the microorganisms?

Yes, you have to do it. Really, it is necessary to do so. How do you accomplish that? By changing the genes of that microorganism. That is what science is all about.

Now you are really talking about science. You know about technology, engineering, and if you want to delve into science, you can study microorganisms. For example, you could modify a microorganism to convert milk into curd in 10 seconds. That is what Hitler tried to do during the Second World War. He wanted to change people, asserting that Aryans were the superior race. He actually separated the best German boys and girls during that time.

They have to get married, and they have to produce children. The best breed, when chosen, will ensure that the children automatically become very intelligent. That is what he tried; unfortunately, that experiment was not successful. However, that is what it means—he did not know at that time about sequencing and all that. So, one of the simplest truths is that when you get married and have children, what are you doing? Nature has chosen all living beings to propagate their own species.

We are not here to pursue chemical engineering or any other job. Our primary purpose is to produce children. We must recognize the nature of this planet; we should not be ashamed of this role. Otherwise, our species will face extinction.

That is why you take anything that has life, even trees. You know, one tree—why should it produce thousands of fruits, and within one fruit, again thousands of seeds? What is the reason? Nature wants to maximize every species in its own way to propagate. If you really observe nature, I mean, I truly appreciate it. Nature aims to maximize every species in its own way to propagate.

And if you look closely at nature, I mean really appreciate it, you will see there are different shapes of fruits and various constructions of them. Why does a coconut have that pit and thick shell? It’s not just there for us to remove and break open. It's not simply for our convenience because the thick casing actually changes its density. The pith, that thick layer, plays a significant role in altering the buoyancy of the coconut. If you take the inner shell, you will notice that its density is different. So, what do you think will happen if you remove all the pith from a coconut and then place it in water?

Yes, if it goes down, it cannot propagate its species. That is why nature has constructed that extra pitch, allowing it to float and travel from place to place. Most of the time, coconuts are found wherever there is a large amount of water; I think that is the ideal environment for them. They travel on the water and, when they reach a suitable location with fertile land, they settle and germinate, leading to the growth of another coconut. Every fruit, like cotton, has a wonderful mechanism for propagation as well.

Now, cotton seeds are present, and cotton has beautiful fibers that allow them to float in the air, eventually falling to the ground where they can germinate. If you look at mangroves, you'll notice some trees with fruits that resemble long sticks, similar to the drumsticks we eat. At the end of these fruits, there is a sharp point. This sharpness is also found in the mangroves that grow near the sea. In coastal areas, there are fluctuations between high tide and low tide, creating a muddy environment in those areas.

So, now that this fruit is ripe, it will simply fall, and the sharpness will diminish. Then, it will stick to the soil and germinate there. Every tree has a wonderful story. That is the essence of nature's propagation. Our job is simply to propagate; in fact, we often don't listen to nature.

That is why we have all the problems. If you listen to nature, I think the planet will be excellent. There is no sustainability because you are designed by nature only for sustainability. However, we have intelligence, and our intelligence is spoiling the planet. Truly, I tell you, we think that we are very intelligent, and then we create all kinds of materials that generate pollution.

That changes the constitution of the atmosphere. So, that is why I think, given the chance, I would want to go back 10 million years to see how people lived without technology and all that. That is what is sustainable. Anyway, good. So, now that is the science I was trying to discuss. I was trying to tell you that if you want to change the genes of this microorganism, you can create a super bug whose sole duty is to convert milk into curd.

So, when you analyze any process involving a catalyst, you may discover that some catalysts are effective under certain conditions. However, science can inform you about the specific type of surface needed for a highly effective reaction, the orientation of the molecules, and how they should interact and arrange themselves to facilitate conversion. Essentially, what happens is that the molecules undergo adsorption, where they adhere to the surface of the catalyst. After adsorption, they break down into various intermediate compounds. These intermediates can then recombine, but the process of breaking bonds requires energy—commonly referred to as activation energy. By reducing the activation energy, the reactions can occur more rapidly. Now, regarding the scientific principles involved, I mentioned the term "Ertl" (E-R-T-L). I'm not sure how many of you are familiar with it, but Ertl's work has significantly contributed to our understanding of the type of surfaces and the surface phenomena necessary for effective catalysis.

Your catalytic reaction must occur in seconds instead of minutes. That is what science is about. Now, I think you at least have an idea of what science is, what technology is, and what engineering is. Science is the highest form of inquiry; it does not concern itself with applications. For instance, genetic engineering started because of this fundamental understanding.

You already have the bugs available; nature created them. You take one of those microorganisms and try to introduce some other genes into it, so that it becomes very, very active. That is my theoretical belief: we can also undergo such changes. There are many science fiction movies now where they perform experiments aimed at creating superhuman beings, like Superman and others. However, these experiments often lead to unintended consequences, resulting in creations akin to Frankenstein's monster. Ultimately, the Frankenstein experiment failed; they aimed to produce the most beautiful and intelligent person, but instead, they ended up creating Frankenstein.

Frankenstein is a devil, very awkward and all that. So, that is what science is, the highest form without discussing any application. They want to know, "Just how do I change this bug genetically?" He never considers whether it will change the curd or if it will affect wastewater; biological wastewater treatment is also performed by microorganisms. Currently, biological treatment takes about two to three weeks. You know those big ponds you have—how do you make them immediately convert waste into some product, or neutralize all the waste, so that it can be easily discharged?

So, that is where genetic engineering comes in. Science is a field where you start with some ideas and ask yourself how to make a process very fast at the molecular or microorganism level. When you apply this to engineering, you have an engineering discipline. For example, we are currently using catalysts to produce ammonia on a large scale through catalytic reactions, or we might focus on other reactions where catalysts are involved, such as converting SO2 to SO3. The conversion of SO2 to SO3 is also a catalytic reaction. I can utilize different molecules or other catalysts, but when I am working at the scientific level, I do not worry about which specific operation is involved; I tend not to concern myself with those details.

So, that is why the highest form is science, the application of that to engineering, and now the next highest form is, in fact, technology. Unfortunately, technology can be developed without this knowledge, but if you create it with this knowledge, you achieve wonderful and excellent technology. One example is planes—airplanes. Airplanes cannot be built by trial and error; science is essential there. That is what makes the technology wonderful, because they are applying science and also engineering. From science, they progress to engineering, and from engineering to technology, leading to the production of airplanes.

I tell you that the maximum technology is found in airplanes, and the next most advanced is electronics. The correlation between electronics applications and theory is very rapid. The moment a theory is developed, a product can be created immediately without any time lapse in between. In contrast, in mechanical engineering, chemical engineering, and civil engineering, it takes a minimum of 25 to 50 years to implement new theories. For example, if I develop a new theory in chemical engineering, we are discussing micro-reactions and micro-reaction engineering.

Even now, I think it's almost 75; it’s nearly 35 years. However, we still do not have ready-made plans for that. The theory is different for us, particularly in mechanical, chemical, and electrical engineering, and even in combustion. For example, when I develop a new theory for combustion, I cannot immediately apply it; it takes time, a slow process of trial and error to see whether it works or not. In contrast, in communications electronics, the moment you have a theory, it is immediately applied; for instance, a satellite is set up right away. In these two areas, the gap between actual practice and theory is very, very small. In fact, medicine operates similarly. When someone discovers a new piece of equipment, it is immediately used on patients.

But chemical engineering, civil engineering, mechanical engineering, and metallurgy require at least 20 to 50 years of experience. This is what I wanted to share, as I know you have the class. I will close it for now. I think we will continue tomorrow morning.