My great pleasure to introduce the distinguished lecture today, and this is the grand finale for the Purdue Engineering Distinguished Lecturer Series this academic year. This is the eighth distinguished lecture this year, and we have had fantastic speakers throughout the year in different views. And today is very special because finally we get to talk about the people factor. And as Donna mentioned, that today's speaker holds a special place in the world of engineering education. She is the Richa Wayland Professor of Mechanical Engineering from Stanford University, where I had spent some time as a student. And her impact is felt in industry, academia, and also nonprofit world. I think that she had her PhD from Michigan here in the Midwest. We'll have to be careful with that. But at least it's. Yes. Well, we welcome her back to the Midwest. And she worked in Detroit with the three big automakers. And then she also spent a lot of time with the Carnegie Foundation for Advancement of Teaching. And over there, she initiated multiple major national centers in the field of engineering education. Then she also served in multiple roles at Stanford, including, I think, associate chair of the Department of Mechanical Engineering, the associate vice provost for graduate education, and then also the chair of the Faculty Senate at Stanford. Her impact is felt both in scholarship and across society. She is the force behind multiple major national initiatives. And she also has been recognized with multiple awards, including two top awards in ASWE. Now there's one particular award that I know very well is extremely competitive and prestigious, the Gorsuch Award for Teaching at Stanford. It is the highest award for teaching excellence at Stanford. And I know that only the very best teacher in the world stand a chance to compete for that. And our speaker here today received that a few years ago. So it's such a great pleasure to welcome Sherry Shepherd from Stanford to talk about something very timely and important, and may I say, holds a special place in terms of excellence and history here with great pride and heritage in the School of Engineering Education at Purdue. So thank you so much, Sherry, for visiting us. Yeah. Yeah. Good. Great. I do feel like I'm coming back home being in the Midwest. My roots are in Wisconsin. As well as in Southeast Missouri, if I say the name correct. So it's good to be back here. I have to admit, right now I'm a little bit envious of all of you. You're at the end of your school year. We just entered week five, and we have five more weeks ahead of us, so our term, we're on the quarter system, goes until the middle of June. I have to say, where it switches for me has come the end of August and September, when all of you are heading back to school. We're just, you know, ramping up for the new school year. So congratulations on almost being done with a new academic year. So you've been working a little bit on your assignment. If you don't have your five adjectives, or three adjectives, if you could write those down, it would be great. And then we'll go on to the next thing we're going to do with that worksheet. Who has three adjectives? OK. Great. OK. So what I'd like you to do next is more quantitative. So I'd like you to turn to the person next to you, and you've got a scale that goes from 0 to 100. And as engineers, we like numbers. And this is the cohesiveness and consistency scale. So I'd like you to compare sketches and adjectives. And on a scale of 0 to 100, kind of say, are you consistent with one another? That would be 100. Or you're totally inconsistent, that's 0. Or is there elements that are consistent and elements that are not, which would put you kind of in the middle? So turn to the person next to you and figure out what your scale should be. Ah, OK. Great. That's perfect. Thank you. That's very helpful. Yeah. Perfect. Thanks. OK, thank you. And you could join them too? Yes, I was going to, but I'm thinking of my average. OK, OK. This is my set. OK, that's why I'm here. I was trying to think of a word that describes somebody who thinks about users of. So that's 50-50, 2 for 4, 1 half.  So who has an alignment score who's still working on it? OK, if you can take about 30 more seconds to figure out where your X is on that 0 to 100 scale, that would be great. Their partner are in the 90 to 100 range. Anyone? Nobody, OK. Who is in the 40 to 60 range? OK, so let me call on a few people. The two people in the back, what did you agree on and what was different in your visions? OK? OK. And then what did you disagree on? And what were your pictures of? OK, that's OK. The assignment could go on. OK, somebody else who was in the 40 to 60 range.  So anybody else have a gender to their person? Anybody else? Yeah, OK. So gender might be there. Did anyone have somebody who might be in a wheelchair? OK, OK, great. And anybody in the 0 to 30 range? Yes, OK. What were you disagreeing about it? Yeah? Yeah. OK, great. Good. So thank you. This was a warm-up exercise, really, to have us all recognize that this thing, what is an engineer, who is an engineer, is a really complex problem. There's no single answer.  Were you drawing the image that you want to attain? I mean, there's a lot of ambiguity in this whole assignment. And I would say, this actually assignment really is suggested by the draw an engineer test. So I didn't create this kind of the maybe some of the new elements are starting to be those adjectives. And I've been using the idea of descriptors with my students. So this is a word cloud from 80 sophomores that I taught in the fall in a strength and materials class. And I asked them to come up with five words used to describe engineers, because I wanted to understand what they were bringing into the classroom in terms of their images. And some of those are really great, innovative, curious, logical, persistent, intelligence, dedicated, precise, open-minded, thorough. I also like to look at the words that only a few people answered, because that also says that there are edgier pictures of what engineers could be. And some people talked about us being adept, adventurous, calculated, calm, clear, clever, artistic. OK, that's a good one. But again, that was only said by a very few of the people. I also asked them five adjectives they would use that would not describe engineers. And I didn't give you that assignment, but you could think about that. Any idea what the biggest word was, most often, that we are not? Social? OK. We're not dumb? OK, anything else? OK, you're going to be surprised. We're not lazy, which is a really interesting idea that sophomores are thinking that's something that we aren't in terms of maybe the work habits, the course load. I think one could tease out, why is it that lazy ends up being the dominant one? We're not selfish, we're not unimaginative. Now again, some of the ones that came up that you would not use to describe an engineer, to me are troubling too. We wouldn't be called fun. We wouldn't be called loved. We wouldn't be called sympathetic. We wouldn't be called thoughtful, or well-versed, or whimsical. And so if those are some of your images of what could you could bring to engineering, and you feel like that that's not part of the canon, what does that say in terms of your joining the engineering team, if you will? So this is all really a warm-up to a question that nags me, puzzles me, baffles me, and has intrigued me for a long time, that simple question, how do we make a better engineer? And even that question has a lot of parts to it. So what does better mean? The wonderful group of graduate students I talked with, talked about have we realized the engineer of 2020 report, now that we're at that year. Does that define what a better engineer is? Is it a better engineer, one that's more socially rounded, that's more sympathetic? I mean that, we could spend a long time saying, what is better? What's an engineer? Is that someone with a degree? Is that someone with an image of themselves? Is that somebody who has a job role that says engineer? So even that is a puzzlement of what do you say an engineer is? What does it mean to make an engineer? I use that word intentionally, but is that to educate, to foster, to initiate? We could look at a whole set of words on what's involved in, I've also assumed there's a transition from not being an engineer to being an engineer if we're making something. Who's the we? So is that parents? Is that K through 12 teachers? Is that higher ed teachers? Is that the individual themselves? Is that society as a whole? Is it journalists? Who's the we that's involved in this endeavor of making a better engineer? And then how do, makes an assumption that's kind of engineering like. It's saying, how do we go about doing this? Should we even make better engineers? Should we invest nationally or internationally in that question? And then A, so the question is even posed around a singular individual. And really is it a set of engineers that are endeavoring to do things? So you can see why I sometimes have nightmares or dreams or think a lot about this seemingly simple question and where my work or our work collectively could actually advance our understanding of what engineering is and who's at the table. So I'd like to share with you five ideas that have informed my thinking about the question. And let's start with idea number five. So you know this is the idea that engineering enables many possibilities. So I've got a number up there, 3.9 million. And I have a quiz for you. So is that the number of babies born in the US in 2017? Is that the number of individuals in the US with a US engineering BS degree? Or is that the weight in newtons of 230 average automobiles on earth? Okay, who thinks it's A? Okay, who thinks it's B? Who thinks it's C? Okay, who thinks I was not a very fair person because it's all of the above? Okay, so 3.9 million is approximately the number of individuals with a bachelor's degree of some form in the United States. And that's about 1% of the population of the US. And that becomes really a very sobering number when you recognize how rare engineers are and how possible it is that kids in growing up may have never met an engineer, much less having had a conversation about what the work is. So this really sparks our imagination of how can we give more interactions or sponsor more interactions between engineers and the more general public and K through 12 students. So in terms of thinking about the pathways of those engineers or the people with an engineering degree, it's also interesting to look at how many of them go on to get master's degrees. So about 20% of them go on for masters. What you also see is about 17% of them choose masters or graduate programs in other things other than engineering. So it might be an MBA, it might be a medical degree, it might be a law degree, so other things. And actually that's a healthy flow, if you will, as well. What you also notice are those two other little pathways into that master's. And some of them are people with non-engineering bachelor's degree. And that's also an interesting recognition that to do graduate work in engineering does not mean that you have been on the engineering train all along. And then also there's this interesting group that had no bachelor's degrees that go on and do graduate work. And so what's happening and who are those individuals in terms of their pathways? And then we've got a smaller group, 3.6% of that original 3.9 million individuals that go on for engineering PhD. Some of you are in this room, you know. And some of you don't have engineering undergraduate degrees and some of you do. So this is kind of a pipeline thing looking at the education. Of the 3.9 million educated engineers, 3.6 million are in the workforce. Okay, so what are some of the reasons that that 300,000 aren't in the workforce or aren't counted by the US Department of Labor? Yes. They've retired, yes, okay. Other things that maybe aren't in for pay. They're doing volunteer work, okay. Other reasons people might not work for a while. They're unemployed, okay. They might, yes. They could be going back for a graduate degree so they would be out of the workforce in the official. Now they'd be counted probably if they had an RA kind of thing that it gets complicated of who you count as being in the workforce or not. Other things people might do. They could be a parent or they could be taking care of their parents. So there could be family reasons why they could be sick. So there's lots of reasons to understand why people might choose or be forced to not be in the workforce. Or they could have done a startup and be retired at 35. Who knows what their stories are, but they're an incredible interesting set of stories I'm sure to be found on why there's that difference between the educated and in the workforce. So we've got this 3.6 million. Now the question for you is how many of, what percentage of those people in the workforce are actually working as engineers? How many of you think it's 80 to 100%?  Okay, okay. 50 to 80%, okay. Less than 50%. Okay. So this is the number of people working as engineers. So, and the overlap between the number working as engineers and the number educated as engineers is 35%. That means of that 3.6 million people who got bachelors in engineering, 35% of them are working as engineers. This is also interesting because it shows us with that blue that's outside of the green circle is there are people working as engineers and the US Department of Labor has an official definition of what is engineering work and what is not engineering work are doing this engineering thing without an engineering degree. In some cases, they have no degree and they've worked in an environment and in a field for a long time and built up their tacit knowledge and are very expert in that. In other cases, they may have been a physics major, they may have been an English major and they make a transition to actually working as engineers. So this is interesting from multiple standpoints, you know, how do those individuals without the engineering degree get to be engineers? What are their pathway stories? And then what's the story of all these individuals who've invested in an engineering degree that aren't working as engineers? Is that a loss or is that something to celebrate because in fact that degree opens up a number of possibilities? All questions that could be searched and should be searched and understanding who engineers are and what their pathways are. Okay, this is another really interesting picture of that 3.6 million. So this is an interactive visual on the US Department of Labor's website and it's interactive in that you can highlight, for instance, you can highlight engineering and it will show you all the places that engineers go in terms of their employment. So if I was interested in those people who'd gotten psychology undergraduate degrees, I could see where they go in terms of their work. I could also play it backwards. I could say we've got all these managers of non-STEM, what were the feeding into those positions from the various degrees. You can also play with this in terms of gender so you can look at the patterns for women and for men if you're going with the gender binary. And you know, I put this up here because it really emphasizes there's lots of pathways and lots of possibilities in terms of an engineering degree and I also really challenge all of us to think about what is the visualization of the data that we're gathering. As we gather big data sets, how do we make it accessible to a broader range of people to ponder things and ask questions about pathways? Now, I do want to talk a little bit more about this 35% because there's other data that help us understand that. So this was a study that looked at people's occupation in 2003 and these were individuals that had gotten their engineering degree between 1996 and 2002. So it was a snapshot from 2003 what they were working in in terms of engineering, computing, engineering related roles, management, other science and engineering, non-science and engineering and not employed and what they were doing in 2008. So over that five-year window what happened to them in terms of did they stay in engineering and where did they move into other things? So what we find is that roughly 75% of those that were working in engineering at 2003 are still working in engineering five years later. So that looks like fairly good persistence. We also see that those in 2003 that started out in management associated with engineering, about 23% of them migrated back into engineering. So recognizing someone may start in a non-engineering role and then migrate back into engineering. It's also interesting that looking at over a quarter of those that were not employed at 2003 actually migrated to engineering five years later. It's also, if we read this across a row we can see there is a diaspora of engineers. So from the 2003 while the bulk of them, three quarters of them were still in engineering some of them migrated into these other professions. And I show this because that other picture of the 35% seems so stark and it doesn't really acknowledge that one has a career that happens over a number of years and the 35% number represents those who just graduated with a BS in engineering degree and those who are 80 years old. And so being careful not to over generalize and saying, oh, everybody's walking away from engineering on the day they graduate or the bulk of them there. Most of them are still actually going into engineering as their first job. This is another thing about the engineering workforce that I ponder a lot is representation. And as of 2015, 14.5% of all practicing engineers in the US are women. On the number has been slowly creeping up, but very slowly. And in my own field in mechanical engineering, it's the lowest representation of women of any field that's 8.6%. In the background on this slide, you see the messier table on which this was pulled from. And if you looked at the table, the one thing that isn't there that increasingly informs or should inform thinking is intersectionality. So the data that was represented in the back figure doesn't look at the combination of gender and race. And what does that say in terms of the unique experiences of individuals? But I think we are making inroads by having those classifications, but we still have things to ponder on why these numbers are relatively low. So that was kind of a dim sum or a data sample from a brand new report, now so new, that came out in December called Understanding the Educational and Career Pathways of Engineers. It's available free. The National Academy of Engineering. The National Academy of Engineering is a foundation in Washington, DC that does several things, including honoring people who've made major contributions to engineering, but they also do studies. And these may be studies that Congress would like to see done on a particular technical issue or studies like this, which is really around what is the health of the engineering workforce in the United States. And I happen to be on the author team of this report. So highly recommended in terms of looking at lots of data tables and information, which I just showed you a few of them. I was primary co-author of chapter three in the volume. And this chapter I'm actually proud of and happy with because it really looked at the social science of people being in engineering and what attracts them and what sustains them in engineering and what sustains them in the workforce. And this is the social cognitive career theory that really talks about how people inputs and learning experiences ultimately map into goals around staying in engineering. And so we use that as a window into the various stages an individual would go through in persisting. And I really wanna shout out to my primary co-authors, Nadia Fuat, who's at the University of Wisconsin in Milwaukee and Amy, Jester Nick Will, who's at the University of Colorado, who were terrific co-authors. And I wanna flag Nadia's other work. So she has an incredible study out called Stemming the Tide that looks at women engineering graduates and what their career paths are a few years out and longer term. It's actually a very influential national study on that question. And then Amy's work has largely focused on the question of how does service learning and working in international scenes translate into career goals? And what are the kinds of places that individuals who have chosen to have a significant component of service learning in their graduate or undergraduate studies, how does that translate into where they had career wise? So really good work to think about. I also wanna flag some of the cool appendices. Let's see the cobweb model of the engineering labor market. So two of the members of this committee were economists, which were a real learning experience for me in terms of working with economists, but it's a model on does the market solve the problem? So if you say that the problem is under representation of minorities and or women, an economist might say, well, if it's a problem, the market will solve it. Our salaries will be higher and we'll attract more. We could talk about whether that works or not. And the appendix E is advancing our understanding of engineering education, pathways, employment, dynamics and economic impact through the innovative use of administrative data. So if you like data, this is also a really good place. Okay. So we could talk about implications. Instead, I'm gonna actually give you a choice on where we head now for this talk. So you've heard the design near adventure thing. We have four different paths we could go through now on where I head with this talk.  So that'll also let you know what the other interests are in the room. So I could talk about what is engineering work. So we've done studies that have done a dive into really looking at an ethnographic manner on what is the real work of engineers and how does that vary depending on where you are. And then what are the implications on where do you learn to do that stuff? To what extent do you learn it in school? To what extent do you learn it in the workforce? So we could talk about that. We could also talk about what things in school seem to matter. And you could say matter in terms of what way. The large focus of that would be on internships and what role they play in building self-confidence among students in a sense of agency and direction. We could also talk about the power of belonging. So what is the responsibility of faculty and an institution in making students really feel like they belong in the classroom and what are some of the practical things we might be doing to increase that sense of belonging for everyone. Or we could talk about expanding what we teach. And there I would be talking about a new course that we introduced about four years ago called Expanding Engineering Limits, Culture, Diversity, and Equity that essentially looks at who's at the engineering table, who's not at the engineering table, and how can change be driven within the academy and organizations. So tough choices. I'll pause for about 30 seconds, and then we're going to do a vote on 4, 3, 2, and 1. And I'm just going to ask you to put up fingers, like 4, 3, 2, 1. OK. So fingers up. All right. OK. So it looks like I'll start with 4. I'll start with 4. And then if there's time, I will go to 2. 4 is kind of nice because it's the next in the set. So in this study, we looked at, and this was actually an interview study, talking to early career engineers. I won't say young engineers, but early career engineers, who'd been out in the workforce for a year to two. And we were really using a critical incidence approach, which means you talk about, in interviewing someone, you ask them what happened along this line of things. And they talk.  And we asked them along the lines of an incidence in their work where they really felt they were being innovative. We also asked them for an incidence that was a high point for them. And we asked them for an incidence that was a low point. And then you take those transcripts, and you have them transcribed, and then you use coding to actually look at what the patterns were. And we happened to use a lens based on this transformative dimensions of adult learning as a set of codes to pull out incidents. And the five categories of stuff that was happening were action-related, so that were they talking about, I had to move those parts from here to here as part of the story. Were they talking about a cognitive dimension of their work? Like that finite element model was really biting me. I couldn't figure out why I couldn't get it to converge. And I had to consider the materials. And so there was a real cognitive component. Was it contextual? They were talking about, well, we couldn't get the parts shipped because there was a strike in Detroit. And so we had to think of other ways of getting the parts there. Was it emotional? Like, whoa, I got praised for my work. Or my boss really just told me that I did that totally wrong. And so there was an emotional component. Or there was a social. I really had to get Mary persuaded to do that. And then I had coffee with her. And then we made that happen. So those were the five dimensions that we took. And you could only code things in one of those five categories. So when you look at those five categories, which one do you think was the most prevalent in their experiences on critical incidences? Who thinks it was action? We're thinking about engineers out there doing their thing. Who thinks action? Who thinks cognitive? Who thinks contextual? Who thinks emotional? And who thinks social? So there's a scattering of. Here's what we found. Well, those are definitions, but. Okay, so nearly 66% of their work was either action, getting stuff done, or social. Cognitive was next at 16%, contextual 10%, and emotional 8%. And so where I find this particularly interesting is I think a lot of our structures in terms of engineering programs are centrally, and not exclusively, in the cognitive domain. But that really is a dominant component of how and what we teach. You know, I think we're making inroads on the social, but what's interesting there is the social that's actually practiced in engineering is not the social we necessarily do in school. I mean, yes, we're having students beyond teams, but you tend to actually be face to face for long hours together as you're eating pizza and you're moving a design project forward. But the social we saw there was much more little sound bites and email messages that you would share with one another and the persuasion and the negotiation of people at a level of hierarchies in an organization. So it's a lot more complex. Okay, so we've also looked at where do you learn the stuff that you need to be practicing? Engineering and a teeter-totter. And so what we found there is stuff that's learned mainly in school, stuff that's learned mainly on the job and learned in both. And what we find, again, based on interviews, this was an interview of 100 engineers in four different organizations, is that learning in school was problem solving, content knowledge, and modeling and analysis. So it's really good to know that some of the dominant things that engineers say they do are learned in school. Project management skills and software skills are a little bit more on the school side. And here's some of the things we see mainly on the job, time management, communication skills, working with people, info-finding skills, equipment and processing skills that are particular to a company. We also saw these being reported only on the job. Organizational skills, context skills, and this is the one that bothers me, work ethic. So for me, that's a major disconnect on why isn't the work ethic we hope that we're helping foster in the academy the same as or complementary to what's in the workforce. So we could talk about lots of implications for that and how are we doing on time, Maria? Okay, I still, so any questions on that one? I'll jump to actually, was it number two I said I would also do? Okay, so I'm gonna go to the power of belonging. So I'm gonna flash through those. Okay, belonging and this is from Jeff Cohen and Greg Walton who are two faculty members at Stanford in the Graduate School of Education. And they define belonging as the perception of being accepted, valued and included. Belonging can help learning by increasing effort and decreasing negative, destructive thoughts. And so we as an institution have really been working with this concept both with undergraduates and PhD students and how can you increase the sense of belonging of PhD students. And we have now purses our provost and the Dean. She sent this memo out back in 2016 and she was really challenging us as faculty in the graduates in the School of Engineering to what are we doing to ensure that the Stanford engineering environment and educational experience is as inclusive and welcoming as possible for all of our students regardless of their backgrounds and our identity. And so we launched that school year with kind of this challenge or opportunity from our then at the time Dean. This concept of belonging is also making its presence in I will call more like teaching manuals. I don't know if any of you have seen the ABC's of teaching book. The first author, Dan Schwartz, is the Dean of our Graduate School of Education. And if you look at it, letter B is actually, B is for belonging. And so they talk about belonging. I wanna show a little bit of a video about this idea of belonging. And it's important in terms of our working with all engineers and all students. But in particular, I think we're being challenged around the sense of, let's see, finding the right thing to press. With first gen low income students. And so more energy around helping faculty understand what does it mean to be more open in working with students. And this is a video, and I'm not gonna play all seven minutes of it. I'm just gonna play a little bit of a teaser. We're a group of a first gen and we call them fly students or they actually call themselves fly first generation low income students produced as a message back to us as faculty on what some of the range of their experiences were and then what we as faculty could do to increase their sense of belonging. So let's play. When people are thinking of Stanford students, they don't think of us. In my family, I am the first one to attend college. Growing up, it was a really big emphasis in my family for my three siblings and I to do as well as we could in school so that we could receive a better education and go beyond working class employment that my parents have been doing their entire lives. I need professors to assume that because most Stanford students come from privilege, most Stanford students come from privilege. Professors will often say things like you've probably already seen this in your AP physics course when some students high schools don't have AP classes or physics. The professor said it as a joke but it's something that's stuck with me about what are our parents paying all this money for. And I was just like, A, parents, no, not me. Paying money, no, not me. There is this talking assignment basically speaking in class and he called me out on the question, describe your bedroom back home in Spanish. And I was put on spot. I just have to take a moment because I just completely had to imagine this bedroom that I never had. When it happens from someone who's teaching here who's supposed to have a relationship with their students, it hurts because it plays into those fears that you have as a freshman of, will people notice me? Will my voice be heard? Hi. So I'll make sure you all have the link. And the next part, it really does move into some really constructive ideas that the students offer about how do you increase that sense of belonging. So I also offer that as an example of how students can influence change by saying there's a problem here and how can we be part of both showing what the problem is but also suggesting solutions. So I'll go back. I want to go here. Let's see. From current slide. Okay. Let's see. A few more things. So a couple of ideas about how we as teachers can think about increasing the sense of belonging. It comes down to in part from me who my teaching team is and really looking at the TAs or course assistants as being part of that larger picture of how can engineers be and how they can think. And this happens to be my teaching team from introduction to solid mechanics, statics and strength and materials courses. We do some intentional activities in a class and I know 80 sounds small here but for us at Stanford that is a large class. How can you include some exercises where students are actually getting to meet one another. We also do some interesting things of taking a large classroom and dividing into pods. And so spades, hearts, diamonds and clubs. So a quarter of the class actually sits together and knows one another more and there's a TA that's assigned to that group to really say it matters that you're here today and how did that exam go and really add those additional personal elements to the class. We also do a lot of hands on. I've given up in this class thinking that the lab is a separate thing you do somewhere else. If this was the classroom, we've designed labs that where we bring the stuff in and so all 80 students are doing the lab at the same time. It does as an instructor, mean you get used to a little more chaos because the noise level and is everybody keeping pace and we've introduced more projects so that students can more intentionally see the connections to the real world and working as teams. So I think there are a number of strategies one can bring in terms of the power of belonging. So with that I think, and the whole complete slide set will be there, I think I wanna do one last thing. So the we is a really important thing because the we is everybody in this room in thinking about the education of engineers and you may have your own ideas in terms of how to advance that idea of the better engineer. And I really want to acknowledge both what's going on here at Purdue and other places in terms of helping nurture an even more thoughtful set of future faculty. You may know about the engineer education pioneers website that Cindy Atman put up but I think we actually need to add another chapter to that. Who are the new pioneers? I happen to be one of the older pioneers. The NSF is supporting more for research and practice grants on engineering education. There are departments, our schools like all of you so you should be applauded and journals and other things. So I think there is a team that is dealing with all of this. So how might our images be expanded? And with that, let's talk. Yeah, so we'll be running mics around. So if you have a question, be sure that you ask it into the mic so it gets. Hi. What are the trends in K through 12 level in engineering education? Okay, well in some ways you have people, well in many ways you have experts in this room that know much more about that. I would say in some ways it's state dependent because states really do establish a framework and whether engineering is part of that framework for K through 12. My understanding is Indiana has recently adopted an engineering framework. Boston or in the Massachusetts has had one for a number of years. I think it does have some interesting challenges in thinking about what is engineering in K through 12? Is it becoming comfortable with computers? Is it becoming comfortable in making things in your imagination? So I think there's really healthy conversations around that. And is the goal of that more engineers or more people having an awareness of what engineering skills are that they might bring into their work? So I think we're making great inroads in developing curriculum and helping teachers learn what it is, but I think there's still a lot of research in terms of particulars. Thank you, nice talk. What is the impact of the work that the group called Fly, FLI is doing? How is it impacting faculty? I know you're doing some things, but what about the general faculty on campus? How are they responding to these needs expressed by the students? I think, and I showed that complete video to the group that I'm in and all the staff were there. And it was interesting, the reaction was many of us had tears running down our faces because realizing how little things you say might be incredibly hurtful to others. What was interesting, we were engineers though, we kind of said, what can we do that's better? And one of the recognitions was the cost of classes. And so a lot of engineering classes, you're making stuff. There's material involved and who is paying for that and how does your ability to pay limit what you're able to do? So now we're working with the Bursar and the Registrar to really figure out how can students get easier access to funds and how can we make our projects less expensive? So I think there's actions on that. Our Center for Teaching and Learning has also developed a set of strategies for use in the classroom. I think there's like 21 ideas for having a more inclusive classroom, particularly around first gen. So in some ways I wish I could say that the provost could say make it better, but that's not how universities work. So it's the Center for Teaching and Learning and all of those individuals slowly working with faculty and showing the video. So I'm curious, is there any here at Purdue some organization that's thinking about first gen students? Okay. Okay. Hey, good. There's a question up there. Hi, so I'm doing research with first generation college students as well and one of my participants, she was already an industry. She was halfway through her program at Aerospace. She got a job as an intern or a co-op actually at an Aerospace company and she was there for about a year. She realized that that's not what she wanted to do. Like she didn't want to be an engineer. And but from my understanding that she didn't want to be the engineer she saw in her company, but not really the engineer that she imagined herself to be. So how, I don't know, I don't know what to do with that. Like how do we move forward and how do we get students to see that like these companies are not the only defining features of engineers, but technically that is where they go into, I don't know. Well, and there are a range of kind of companies and organizations. And so for me, we have another project that's looking at just the school to work transition and the use of the career center and how should internships play in a role in that? And so for me, a question is how can we help students try on organizations to get better insight of what is the culture? And is it a culture that they can imagine being in? Because it's too bad that one might make a decision based on one experience. Nice talk. So you asked me a very tough question during my PhD defense. So this is my chance to ask you one.  Retaliation, eh? No, that's a joke. But there's a lot of reason for what we call the skills gap in the manufacturing industry, for example, and many other industries which are sort of complaining that many of their incoming workforce, which is coming directly from K through 12, is not prepared for it. And if you go to these different companies, they have various levels of skills. But yet the education and content in K through 12 is still the traditional STEM curriculum. Perhaps it's a different kind of STEM that needs to be put in place to prepare them for doing these skilled job in these industries. Do you have any suggestions or thoughts towards this big gap there? That is such a philosophical and political question. So if you look at the German educational system, and I've spent actually a fair amount of time working in Germany, they traditionally have had two routes in high school. One is the university route. So you're being prepared, Gennasium and take the Abitur, which is a test to get into university. And then there's another path that really is getting you prepared for a trade. And that's been well respected traditionally. I think it's kind of fallen away because I think there too there is this belief that the college education is the standard that everybody should achieve. So the philosophical is, do we want to track people early into PAS? Or do we actually recognize that people develop at different stages and rates and you don't want to shut off any options? So I don't have an answer, but I think in some ways states and communities actually need to struggle with that question. There's probably words other than tracking. Yeah, did you have a comment that looked like? On that? One second. Oh, okay. So it's about possibilities and it's quite interesting. So how you show that engineering creates possibilities and but those set of possibilities also sort of underwritten by this political larger context that we function within and therefore, so it begs the question, shouldn't we, the V that you are using also start to worry about that, right? So it means that these conversations that are about policy level conversations are sort of at the heart of the issue or at least very critical. So that's sort of what I was thinking about and I was wondering, yeah, so do you agree with that? And can you say, I want to know what I'm agreeing to or not. So in a sense that so as we care about education of engineers or what constitutes an engineering work, we have to, we are by implication, at least thinking about a political question. So therefore activism in that sense is inseparable from engineering education work. Yeah, I would say, and I would also say that engineers tend to not be that political in some ways. I mean, if you look at the presence of engineers in Congress, we're not very there and that actually bothers me why we're not more because we do have some good thinking skills in that. You know, I do see, and this is kind of anecdotal, some of the women's students really want more than their technical education. So they're involved in a lot of extracurricular things in terms of moving an agenda or a set of agendas. You know, I would say if we didn't, I didn't play the clip in the fly, but we're also recognizing those students have a stress in terms of choosing a major of the fly students that is kind of orthogonal to a lot of the Stanford philosophy. So when you're admitted to Stanford, you can choose any major. There's no required GPAs or anything. And so we really say to students, explore. You know, if you're interested in French literature, think about majoring in that or whatever. The quote from this student is really talking about is he does not have that freedom because he feels an obligation to community to know that when he finishes in four years, there's going to be a good paying stable job. So I think those, the wider range of individuals at the engineering table are actually gonna push us to ask deeper questions. More questions? Someone has a question and is afraid to ask it. Andrew. Thanks for your talk. This is a very generic, like very generic kind of question. So you can take this in any way you want. And so obviously you've had a very long and great career. So over the course of your career, what are some things that you've found particularly surprising? Things like some of the stuff you might kind of expect to see, but what are some things that maybe have really stuck out with you in terms of just things that you wouldn't have ever expected in the course of your research? Okay, how hard it, one thing is how hard it is to affect change. And you got to stay in the game, that a change might seem obvious to you, but there's a lot of politics and persuasion to actually affect change. So they're not quick fixes. Another thing is how engineers are conundrum to me. I am one, or I try to be one. Sometimes I have imposter syndrome too. But as engineers, we like data and numbers. And I'll have colleagues that make arguments based on models, physical models, and then you'll ask them about their teaching and what their strategy is. And there it's kind of seed of the pants. And so we've got this conundrum of wanting hard data and collecting data, but in other parts of our lives, we're okay with just more opinion of things. So I've learned to work with that, and I still have, and I have some of those dilemmas too. I would say another thing is just, and this is, I keep seeing it again, how hard learning is, and recognizing again, there's no easy fix, and how miraculous it is when you watch somebody learn to command something. I mean, that's still just, that there's puzzlement there, they're working hard at it, and then those light bulbs that go off is still is what keeps me in the game, yeah. All right, that's a nice, oh, is there someone else? No, one more question. Yeah. Thank you so much. My question is more on a global scale. I was wondering, I mean, especially that CESA you showed based on the skills that students learn in school and in the practice. I was wondering, have we looked outside the U.S. to adopt, I mean good practices, or have you compared this CESA across? I haven't compared the CESA. I mean, that's a really good question, and that's future research. The one thing I have been, so I'm involved with a center called Unternehmertum, that's part of the Technical University of Munich, and Unternehmertum in German means entrepreneurship. And it's an interesting center that was founded by Maria Klotten, who is the founder of, or the owner of BMW, and she is, Susanna Klotten, she is worried that too many German engineers don't want to take risk and want to work for BMW. And she's worried because new ideas are about taking risk, and it's so orthogonal to the German culture about failing. And so there are some things that they're trying to import from our culture about risk taking, but you're also right in terms of looking at their work, so future research. Yeah, the comparative international thing is very cool. All right, I think that that's it. So if we can all thank Sherry. Well, thank you all for coming.


In the previous class, we have learnt about melting practices. Once we obtain the molten metal, there is a need to treat the molten metal. So, in this lecture, we will be seeing treatment of molten metal. What is the meaning of treatment of molten metal? Treatment of molten metal means removal of slag, removal of unwanted materials or gases from the molten metal. Treatment of molten metal means addition of alloying elements or modification of the solidification pattern. So, all these activities together constitute treatment of molten metal. Means either we will be removing some material or we will be adding some alloying elements or we will be removing some gases or we will be changing the solidification pattern. Now, this treatment of molten metal is carried out at some stage in the sequence of operations shown below. What are they? Once this can be done or this treatment of molten metal can be done when the molten metal is in the furnace. So, this is the furnace or this treatment of molten metal can be done when we tap the molten metal into a ladle. This is the ladle and this is the furnace or this treatment can also be done after we pour the molten metal into the mould. So, this is the mould. At any of these stages treatment of the molten metal can be done. Now, these are the different treatments of molten metal. One is control of chemical composition means here we add alloying elements to change the composition of the molten metal. And next treatment is the initiation of nucleation sites. Third treatment is the refinement of grain size. Fourth treatment removal of gaseous impurities and fifth treatment removal of undesirable elements. And last is the skimming of molten metal means removal of dross, dross means mixture of slag and other impurities mixing with the molten metal. So, this is the dross. So, this dross can be removed in the skimming. Now, let us see all these what say treatments one by one. First, let us see the control of chemical composition. In the control of chemical composition, this is achieved by adding required elements in the form of granules powder into the molten metal. Suppose the molten metal requires suppose if we are melting steel, if it requires chromium we will be adding chromium granules into the molten metal or nickel granules into the molten metal. So, this can be added in the furnace charge or in the ladle. You see this can be done at two stages. One is the furnace charge or in the ladle or at some time after the metal is molten amounts from 0 to several percentage are typically added. So, these are the best examples. In the steel say we require chromium as an alloying element or nickel or molybdenum as the alloying elements. So, these alloying elements will be added into the molten metal in the form of granules. So, ultimately the chemical composition will be changing. Similarly, in the aluminum we add magnesium and zinc, copper these are the very good alloying elements of aluminum. So, these will be added into the molten aluminum so that the composition will be changing. So, this is the one of the treatments that is the control of chemical composition. Now, the chemical what say elements alloying elements can be added like this. Here we can see so this is the furnace, this is the furnace or the ladle. So, in fact this is the ladle and here the molten metal is coming into the ladle and here we can see there is a hopper. In this hopper there are granules are there. So, these are the granules of the alloying elements different alloying elements. So, these will be dropped into the molten metal one by one these granules. So, these granules are coming inside and they will be still and they will be mixed together. Finally, the composition of the alloying what say molten metal will be changed as per our requirement. The next treatment is the initiation of nucleation sites. What is this initiation of the nucleation sites? Initiation of nucleation sites and modification of solidification structure is known as inoculation. So, here we add certain elements to change the solidification structure. The material added for this purpose is known as nucleating agent. In the first case we have seen the alloying elements we were adding here we will be adding nucleating agent. So, that the solidification structure will be changing. So, that the solidification structure will have better properties. This is usually made at some point after charging inside the furnace. Now, amounts are usually small and may be as small as 0.02 percent to be effective. Now, let us see an example production of spheroidal cast iron. This spheroidal cast iron is also known as ductile cast iron or it is also known as nodular cast iron. Now, initially there is a grey cast iron. See, if we see the grey cast iron, so this is the what is a structure solidification microstructure of grey cast iron and here we can see these are the graphite flakes long graphite flakes are there. This helps us in machining. So, they will help us to get the what is a discontinuous chips that way it is good, but mechanical properties may not be very good. So, to improve the mechanical properties we will be modifying the solidification structure. Now, we produce the spheroidal cast iron during production of spheroidal cast iron, calcium or barium or strontium or zirconium or magnesium and even rare earth metals are added in very small quantity to the cast iron molten metal. The elements added to promote spheroidization react with the solute in the liquid to form heterogeneous nucleation sites. Now, these elements that we add as the nucleating agents will be acting as the nucleating agents means they will be spreading all over the melt all over the molten metal. Around these nucleating particles the molten cast iron will be solidifying they will be solidifying like spears that is why it is known as the spheroidal cast iron. The alloying elements are injected into the mould before pouring. Finally, graphite nodules are present instead of flakes. Now, what happens previously in what say grey cast iron carbon was present in the form of the graphite flakes. Now, here because we are adding these nucleating agents around the nucleating agents the cast iron is solidifying so many spears are produced that is why we also call it as the spheroidal cast iron. Now, here we can see this is the structure of the spheroidal cast iron and so many what say spears are there we can see so many spears. So, these are all the graphite spheroids here we can see. So, these what say what say spheroids improve the mechanical properties of the spheroidal cast iron or the ductile cast iron or the nodular cast iron whereas, the microstructure of the grey cast iron is like this it is not so favorable as far as the mechanical points are concerned. Generally, a carrier material is doped with a minor additive or the nucleant which produces the nucleant particles in the iron melt. So, to add this nucleant to the molten metal a carrier material is used this carrier for example, silicon and iron combined as ferro silicon. So, here the ferro silicon acts as the carrier should have the following characteristics it should provide fast and homogeneous distribution of the nucleant in the melt. It should have a composition that is compatible to the melt means it should not disturb the composition of the melt and it should form an alloy between nucleant and the carrier and it should be cost effective. So, these are the what say characteristics required for a good carrier material. Next one let us see the third refinement that is the third treatment that is the refinement of grain size. What is this refinement of grain size? Grain refinement is a method of strengthening materials by changing their average crystal or grain size. The additive used for this purpose is known as grain refiner. Now, these are the typical grain refiners for various casting alloys. So, these are the metals for cast iron the grain refiners are ferro silicon, silicon calcium and graphite. For magnesium alloys the grain refiners are zirconium and carbon. For copper alloys the grain refiners are iron, cobalt and zirconium. For aluminum silicon alloys the grain refiners are aluminum 3 boron, aluminum 4 boron, aluminum 5 titanium, aluminum 1 titanium 3 boron, aluminum 5 titanium 1 boron. And for lead alloys the grain refiners are A S and T E. Next one for zinc alloys it is the titanium and for titanium alloys aluminum, aluminum, titanium, intermetallics. So, these are the what say grain refiners used for different molten metals. Method of grain refinement, how these grain refiners are added to the molten metal? One is grain refinement using master alloys. Next one grain refinement using carrier gas for or for powders. Next one using electromagnetic vibrations. In the case of the grain refinement using master alloys grain refiner master alloys will be made in the form of rods or bars. So, these generally these are made as the circular rods. So, these can be turned on a lathe machine and chips can be produced. So, chips will be produced by drilling or they can even be drilled and the chips can be removed. So, these chips will be added to the melt after it is tapped into a ladle. Next one this is the second method of grain refinement. Grain refinement using carbon powder with carrier gas. Now, here we can see this is the molten metal. So, this is the base metal is magnesium here. So, it is inside of electric furnace.  Now, this carbon powder is kept in a chamber we can see here. So, this is the chamber now this is the argon cylinder. From the argon cylinder the argon gas will be coming and here we can see a unit for pulsating motion right. So, means at one stage the motion will be high at one stage the what is a movement of air this argon gas will be less. So, it will be going inside this chamber and it will be taking certain amount of carbon along with that then it will be going inside the furnace and it will be mixing with the molten magnesium. Now, this carrier gas is inert gas. So, it does not react with the molten metal, but only the carbon powder which is going along with the carrier gas will be mixing with the molten metal and grain refinement will be done because of the carbon powder. So, this is another method of grain refinement means using a carrier gas. Now, let us see the third method of grain refinement using grain refinement using electromagnetic vibrations. And here we can see this is the molten metal right. So, this is the we can see here this is the vibrating rod and here we can see piezoelectric transducer. When we pass electricity through this piezoelectric transducer this electrical energy will be converted into mechanical energy means this vibrating rod it will be making vibrations ultrasonic vibrations. Because of that here we can see this is the solidifying melt the grains will be refined their size will be changed that is how the grain refinement will be done using electromagnetic vibrations. Till now, we have completed three treatments that is the control of chemical composition initiation of the nucleation sites and refinement of grain sites. Now, let us see the removal of gaseous impurities removal of gaseous impurities the absorption of gaseous persists in ferrous as well as non ferrous gaseous in every molten metal there will be gases and gases will be absorbed at different stages of melting. So, there is no exemption every molten metal is prone to absorption of gas then what are the gases absorbed by the molten metals. So, these are the common gases absorbed in molten metals. So, iron metal the gaseous elements absorbed are hydrogen, oxygen, carbon and nitrogen then these gases will be coming out of the casting as the molecular gases like carbon monoxide carbon dioxide H2O, molecular hydrogen and molecular nitrogen initially they are entering as the what say atomic elements and they are coming out as the molecular gases. Next one when the base metal is copper the gaseous elements absorbed are hydrogen, oxygen, carbon and sulfur in turn these will be coming out as sulfur monoxide, sulfur dioxide, carbon monoxide, carbon dioxide and H2O. So, these are the molecular gases coming out from the casting during solidification. Now, this is the magnesium melt the gaseous element absorbed is hydrogen initially it will be going inside the hydrogen melt as the atomic hydrogen, but it comes out from the casting during solidification as the molecular hydrogen. Similarly, when the base metal is aluminum the gas element absorbed is atomic hydrogen, but it comes out from the casting during solidification as molecular hydrogen. Now, the question is from where these gaseous elements are coming how they are entering into the molten metal one source is atmospheric humidity, so in the atmosphere there is what say humidity. So, because of that there is always moisture now we keep the what say molten blocks are the charge several times outside the charge that is kept outside will be absorbing moisture and that charge will be kept inside the furnace and we melt it that is how the hydrogen will is trapped and also oxygen is trapped. Next one, so even this wet metallic charge is the same thing next one wet furnace lining most of the furnace they have lining refractory lining will be there. Now, these linings can absorb moisture because of the humidity in the atmosphere now what happens when we put the metallic charge inside and when we heat this moisture will be decomposing and it will be forming hydrogen and oxygen that will be going inside the molten metal. Next one wet foundry instruments means for steering purposes we used to insert some rods and we used to stir the molten metal that time these what say foundry instruments may have moisture this moisture will be decomposing and it will be releasing oxygen and hydrogen. Next one wet fluxes and other consumables we add fluxes into the molten metal these fluxes are sometimes they contain hydrocarbons these hydrocarbons will be decomposing and releases hydrogen and other consumables also may contain other gaseous elements. Next one furnace fuel containing hydrogen sometimes most of the times nowadays we use electric furnaces sometimes we also use what say oil fired furnaces oil fired furnaces what is there what is the fuel we use some oils as the fuel. So, these are the hydrocarbons when these hydrocarbons are burning what will happen hydrogen will be evolve. So, this hydrogen will be going inside the molten metal. So, these are the sources of gases in the molten metal now the question is so what if the gases are going inside the molten metal what is the problem what are the adverse effects of the dissolved gases one is the gas porosity defects we get gas porosity on the defects. Second one hydrogen induced cracking this is also known as cold cracking third adverse effect of dissolved gas is hydrogen blistering. Now let us see all these details now this is the first adverse effect of gas absorption in the molten metal. So, we get the gas porosity on the casting here we can see this is a casting, but the solidified casting is ok, but on the surface of the casting we can see so many small small what say holes are there tiny holes are there we can see several holes are there this is due to the absorption of hydrogen gas. The hydrogen gas will be releasing from the casting during solidification and it will be occupying on the surface of the casting that is how there are several holes on the casting. So, this is the gas porosity defect this is the second adverse effect of gas absorption in the molten metal hydrogen induced cracking this is also known as cold cracking what is this now here we can see this is the what say hydrogen we can see these are all the hydrogen these hydrogen atoms are going inside the molten metal at several stages may be during what say melting in the furnace. So, it is going inside as the atomic hydrogen yes, but after what say we pour the molten metal into the mould during solidification what will happen initially crystals will be forming these crystals will be enlarging and they will be forming grains. Now, these atomic what say hydrogen they will be what say making bond with the neighboring atoms. Now, it will be forming into molecular hydrogen it is entering as the atomic hydrogen during solidification it is becoming as the molecular hydrogen.  So, this occurs when the what say casting pulls down it does not occur when the casting is in a hot state when it occurs only when the casting pulls down that is why it is known as the cold cracking. So, this is very what say severe adverse effect of gas absorption in the molten metal and another adverse effect is hydrogen blistering what is this here we can see this is the casting and here we can see here there is a hydrogen atom is there and here hydrogen atom is there. So, hydrogen atom and hydrogen atom they become molecular hydrogen now they are trapped inside the grains inside the casting they will be exerting some pressure that is how there is a bulging of the casting you see this is the bulging of the casting actually the casting should be like this the casting should be like this there is a bulging. So, this is known as the blister and inside there will be gaseous what say what say presence will be there gas presence will be there. So, this is a another severe defect and it is the blistering or blister formation. So, this is another adverse effect of the gas formation now how to remove these gases how to removal of removing the gases impurities intensity of hydrogen is more in nonferrous castings especially in aluminum castings all the molten metals absorb gases, but in nonferrous alloys it is more absorption of gases is more especially in the aluminum alloys. So, allubility of hydrogen in liquid aluminum at its melting point that is 660 degree centigrade is 2 point c c per 100 grams whereas, solubility of hydrogen in solid aluminum is just below its melting point is just 0.05 c c per 100 grams thus the dissolved hydrogen causes porosity in the castings as it is released. Now, here we can see solubility of hydrogen in aluminum in the solid state you see the hydrogen solubility is this much whereas, during melting once it is a liquid metal the hydrogen solubility is 4 times or even 5 times in most of the above cases moisture or vapor from different sources react with the liquid aluminum and release hydrogen. You can see here here we can see aluminum and of water reacting aluminum oxide and nascent hydrogen is released this nascent hydrogen can do any harm to the casting it can go inside and it will form the molecular hydrogen and it causes cold cracking or the hydrogen induced cracking also or it can also cause the blistering. Now, how to get rid of these gases de-gassing methods de-gassing is the most effective way of reducing porosity different de-gassing methods available are de-gassing by tablets de-gassing by fluxes rotary de-gassing ultrasonic de-gassing and the vacuum de-gassing let us see this one by one de-gassing by tablets chlorine is the element in which hydrogen diffuses very much. Now, what we do is we insert the chlorine tablets inside the molten metal. So, chlorine tablets are forced deep into the bottom of the molten metal bath by the help of a metal plunger or the baskets. Now, chlorine generated by the de-gassing tablets takes away the dissolved hydrogen and other gases. So, these are the typical chlorine tablets and the it is their formula is C 2 C L 6. So, these are the tablets. So, these tablets can be forced deep inside the molten metal once we dip these tablets inside the molten metal chlorine gas will be released this chlorine gas takes away the all the dissolved gases. Now, next method is de-gassing by fluxes. Mixer of chloride based fluxes is sprinkled all over the bath of the molten aluminum. Now, here we sprinkle chloride based fluxes. The flux components react with aluminum forming gaseous compounds like aluminum chloride aluminum chloride etcetera. The gas would bubble and rise through the melt. The bubbles escape from the melt and the gas is then removed by the exhausting system. Next one the rotary de-gassing. In the rotary de-gassing method an inert gas or a chemically inactive gas like organ or nitrogen is perched through a rotating shaft and rotor. Energy of the rotating shaft causes formation of a large number of fine bubbles providing very high surface area to volume ratio. Now, this large surface area promotes fast and effective diffusion of hydrogen into the gas bubbles means what we are doing is here we can see. So, this is the melt and so this is the shaft and it will be rotating and here we can see there is a rotor and this is the liquid aluminum. Now, we will be passing organ or nitrogen. Both these organ and nitrogen they are chemically inactive with the molten aluminum. Now, this will be passing through the rotor and through the rotor they will be released and the shaft is rotating and they will be released and they will be forming bubbles tiny bubbles. Now, these bubbles have a tendency to adhere with the what say hydrogen. So, hydrogen gas will be coming and it will be adhering with the gas bubbles of organ or nitrogen and they will be coming out they will be coming up and at the top there will be exhaust system will be there. So, it will be to what say all the time it will be pump taking and collecting all the gas and it will be sending out that is how the all the gas both the organ or the inactive gas or the carrier gas and the gases that are observed in the molten metal will be removed from the molten metal. So, this is the rotary degassing and it is very effective. Next one ultrasonic degassing the injection of ultrasonic vibrations in molten aluminum causes alternating pressure in the melt. Now, cavities appear as a result of tensile stress produced by an acoustic wave in the rare fraction phase. The gases elements diffuse into the cavities some of the dissolved gases escape when cavitation bubbles at the molten surface collapse. Now, here we can see this is the modes of the ultrasonic degassing nucleation of cavitation bubbles on nuclei usually. So, these are the solid inclusions containing cavities because of this there will be growth of the bubbles due to diffusion of hydrogen atoms from the surrounding melt to the bubbles. So, when what happens is during this ultrasonic degassing there will be nucleation of cavitation. So, because of this the hydrogen atoms in the melt will be diffusing towards those that nucleation region. Next one covalence of bubbles to form the large bubbles finally, float of large bubbles to the surface of the molten metal and escape of bubbles at the tau melt surface. And here we can see this is the chamber used for ultrasonic degassing and here we can see this is the ultrasonic transducer and this is the electric furnace and this is the vacuum chamber. And here the molten metal will be there and this will be causing the ultrasonic vibrations. Now, what are the advantages of ultrasonic degassing? No moving rotating parts in the degassing system. So, the system is more robust in this case of the rotary degassing what is happening all the time the rotor is rotating. So, that is how the what is a system may be what is a shaking, but here there is no such case the system is robust. Fast degassing the bubbles formed in this technology are much smaller than those in a conventional degassing system. Minimal capital investment and also the operating cost the capital investment is not very high less draws formation. Draws means mixture of slags, unwanted materials and molten metal. So, that is the draws sometimes this draws will be floating on the molten metal. So, here in the case of the rotary degassing because of the rotation of the rotor this draws will be collecting at the top of the molten metal. And removal or segregation of the draws sometimes becomes tough, but here less draws formation. The melt surface is not disturbed due to ultrasonic degassing the melt surface is not disturbed. Once it is disturbed what will happen the top layer will come to the bottom, bottom layer will go to the top means new new what is the surface is exposed to the atmospheric oxygen. And hence there will be oxidation, but here all the time only one layer one what is a region is exposed to the what is a atmospheric conditions. So, here repeatedly different surfaces are not exposed to the atmosphere. So, that is an advantage. Next one the vacuum degassing here we can see this is the molten metal. And here we can see this is the vacuum pump and here it is the addition of hopper if we want to add any alloying elements and also this is the vacuum chamber. Now, from one way we are sending the inert gas that is the argon. This argon will be going and the we are getting the molten metal like this you see it will be falling into this container. Now, because of this now at the same time we will be applying the vacuum because of that the gases that are present inside will be removed. Other precautions to reduce gas absorption use big pieces of molten charge metal charge as they are least susceptible to contamination. Second one avoid the use of contaminated scrap. Next one use preheated charge most of the times the charge what is a contain some moisture if we heat this moisture will be removed. Next one alloy additions fluxes and ladle tools should be perfectly dry. If these what is a fluxes or the ladle tools are not dry or if they contain some moisture then there will be gas absorption by the molten metal. Next one avoid overheating of the melt. If we what say overheat the melt what will happen it will be observing more and more gases allow the molten metal to cool slowly so that a large portion of dissolved gas may escape. Longer the time of solidification what will happen longer the escape of the gases from the metal. That is why allow the molten metal to cool slowly so that a large portion of dissolved gases may escape. Next one removal of undesirable elements so this is the fifth treatment of the molten metal removal of undesirable elements. First of all what are the undesirable elements in the molten metal the common undesirable elements in castings especially these appear in steel castings in steel they are excess of sulphur excess of phosphor. So these are the undesirable elements now these must be removed. So removal of excess of sulphur from the melt is known as desulfurization means sulphur content is removed it is reduced. Similarly removal of excess of phosphorous from the melt is known as dephosphorization. So this excess sulphur excess phosphor must be removed desulfurization desulfurization means removal of excess of sulphur from the liquid metal. Sulphur in steel is removed by adding small quantity or amount of manganese to the melt. So this manganese reacts with sulphur and forms manganese sulphur and it comes out along with the slag that is how the excess sulphur in the molten steel is reduced. The desulfurizing agents are injected into the molten steel by the following methods. Manganese powder transported is transported by an organ gas is blown into the steel through a lance means lance means a long pipe. So manganese powder which reacts with the steel and forms sorry with sulphur and forms manganese sulphur is transported into the molten metal through a lance. Next one corvair containing the powder of desulfurizing agent means this corvair contains the powder of manganese that will be continuously fed into the molten metal. Now here we can see this is the powder injection desulfurization unit. So this is the what say liquid steel now there is a lance is there. So this is the lance means a long pipe. Now we are sending organ plus desulfurization powder means the what say here we can see that is the manganese powder. Manganese powder and organ is sent through this lance. Now what will happen this manganese will be reacting with sulphur and forms manganese sulphide and that will be collected as this lac at the top and it has to be removed. And here we can see this here is a system for fume extraction. So that is how the excess of sulphur can be removed from the molten steel. So that is the desulfurization. Next one this is the corvair desulfurization unit and here we can see this is the liquid steel and this is the wire guide is there. Now here there is a corvair is there. This corvair takes the what say manganese powder along with that and this corvair is continuously fed into the liquid metal. This manganese again this manganese powder reacts with what say sulphur in the molten steel and forms manganese sulphide. Again it will be coming up as the slag and it has to be removed. Again here we can see there is fume extraction system is there to what say remove the hot gases and fumes. Now there are other desulfurizing agents are there. Sometimes slag mixtures also act as the desulfurizing agents. Slags are unwanted materials in the molten metal but they help us to cause the desulfurization or to remove the sulphur content in the steel. Here we can see this is the CAO it can present from 50 to 90 percent and this is the calcium fluoride and it can present from 10 to 20 percent aluminum oxide and it can present up to 30 percent. Now calcium carbide and magnesium lime magnesium calcium and aluminum so these are all the slag mixtures. These slag mixtures will be helping us to remove the sulphur content or to act as the desulfurizing agents. Next one dephosphorization just like desulfurization here there is another method dephosphorization. Dephosphorization means removing excess of phosphorous from the molten steel. Here slag helps in removal of phosphorous from molten steel. Here we can see this equation will reveal us how slag will help us in the removal of sulphur. See here in this equation we can see this is the slag is what is it created so this is the slag. Now the slag should have free dissolved lime is there. So high base city of slag is required for effective dephosphorization. Next one skimming of molten metal. Skimming is a technique of metal refining. It is the removal of dross or any other particles that are floating on the surface of the molten metal. So sometimes the dross will be floating on the surface of the molten metal. What is dross? Again I am telling what is a mixture of slags and impurities they will be floating on the molten metal. Unmounted material this is the dross. Sometimes this dross if it is only floating on the liquid metal yes it can be removed. It can be easily removed. Sometimes it will be going inside the molten metal. At such times it is very difficult to remove the dross. Now how to get rid of this dross? By skimming of molten metal. Now here we can see for this skimming there will be what is a skimming, what is a apparatus will be there. So this is the dross skimming station will is available. So the machine slowly rotates the preheated skimming tool inside the crucible. Here we can see this is the crucible. So this is done after we collect the molten metal from the furnace and when we collect it into a crucible at that time this skimming can be done. So here we can see this machine. So here we can see this is the crucible and here we can see there is a skimming tool is inside. This is this is the skimming tool. So this will be rotating. So at a very slow speed it will be rotating. Then what happens as it is rotating the dross is collected from the molten metal surface and the base material is then placed in a recuperation bin and next to that here there is a recuperation bin is there means like a dust bin. So this tool will be rotating and dross will be though it may be present inside it will be collected because it is rotating because of the centrifugal force what will happen the dross density is very less compared to the density of the molten metal. So this will be collected at the center because less centrifugal force will be falling on that. Now this will be collected at the center then it will be removed and it will be kept inside the recuperation bin. Again it is done in stages again this what say skimming tool will be rotating again the dross will be collected at the center that will be removed and it will be kept inside the recuperation bin. That is how the dross can be reduced removed from the molten metal. Well friends in this lecture we have seen different treatments of molten metal we have seen control of chemical composition means we add the alloying elements. If we the molten metal requires certain alloying elements if they are deficient we add them in the form of granules. So this is the control of chemical composition we have seen. Next one initiation of the nucleation sites this is for modifying the what say solidification structure so that we get better mechanical properties from the casting. So this also we have seen. Next one refinement of the grain size means altering the size of the grains or the crystals and we have also seen another treatment how to remove the gaseous elements from the molten metal in different cases we have seen. Next one removal of undesirable elements we have seen how to remove undesirable elements like sulfur and phosphorus we have seen. Finally removal of dross from the molten metal that is the skimming of the molten metal. So these are the different treatments given to the molten metal. We will see in the next class the fluidity of the molten metal. Thank you.


What's going on, you guys? Welcome to the Single Guy channel. I am not the single guy, but I have an important question that I'm going to talk to you guys about. So my name is Lloyd, and today we're going to be talking about what women like more than sex. In fact, I would say they need this more than sex.  In fact, the older I get, the more I realize that women don't like sex just as much as men. They probably like it more. Okay. And you know, the more you learn this, the more you hang out with them, the more successful experiences you get. It's just that women, when it comes to men and women, they both want it just as much, but they want it in kind of different flavors, meaning that women are more particular about who they have sex with. And men are a little less particular about that. They both want it just as much, but for women, it's a little bit more of a big deal for a variety of reasons. Okay. So women like sex just as much as men, but what do they like more than that? Okay. This is going to surprise some people, and I'm going to come at it from a different standpoint than I think a lot of other, other people have talked about it. Okay. What women want more than sex is a sense of belonging. Okay. Now, what do I mean by this? I mean that a lot of times you'll find a woman will pick a partner, a woman will pick somebody who, although they might not desire as much, they pick him for security reasons. Maybe their family likes them more. Maybe they're thinking about having kids and they feel like this guy would be a better option to take care of the kids. They've sacrificed some pleasure that they would get from sex to be with a man that they generally think would be just overall good. They feel like they belong more into them. Typically this guy is someone who agrees with their culture more, their parents like more, you know, it's kind of like the job that they want. They feel like they belong in that environment. I can't tell you the number of women that I've dated who we had amazing sex.  Why would they pick that guy?  Like that's not the lifestyle for them. They don't feel like they belong in that environment as much. So they sacrifice a little bit of pleasure that they would get from me to be with someone who they feel like they belong with. So where does this feeling come from? This feeling comes from the fact that women are constantly scared in life. They don't go around the same way that you do. If you walk down the street, you feel probably okay. But for a lot of women, they don't. They sometimes feel scared. If they're in an environment where they don't know anybody, they feel it very strongly. Women are smaller and weaker than men. And so as a result, they feel like they're more at risk. They feel like they're more of a target because a lot of guys are trying to get at them. So if you put yourself in their shoes, you begin to realize that this nagging fear, this nagging doubt, this voice in their head that's telling him all these negative things is a really strong factor in the way that they do things. And if they find a position, if they find a situation, if they find a person that allows them to alleviate that voice in their head that makes them feel more secure, it's a huge sigh of relief. It makes them feel really great. Doesn't give them as much pleasure or much desire or like as much fun as they might like, but they will sacrifice that to get that sense of belonging, to get that sense of safety that they feel around people. Women want to feel accepted. They want to have a sense of belonging and fit in. That's why they like social causes. That's why they support each other. That's why they do all of those things that a lot of men get confused by. Why do women do that? It's because they'd like to have a sense of community. They'd like to have a feeling that they belong in a certain area. I give you the example about a girl who will marry someone who might not necessarily be the most desirable guy for them, but they marry them because they get a sense of belonging from them. But also too, women will join friends groups. Women will hang out with certain people that might not be the best for them, but they feel like they belong with them. They feel like they have a sense of acceptance. Once you understand this, once you understand that she's looking for a sense of belonging, you can give her both. You can give her an intense amount of desirability and you can give her a sense of belonging. If she feels like she belongs with you, if she feels important, that's going to be a huge factor in keeping her around. Yes, the sex part is good, but ultimately I'd say that women enjoy being in an area where they feel like they belong. If you can give them both, that's the ultimate thing. But at the end of the day, if they have to pick one, I find a lot of women. When they're younger, they choose sex, they choose desire, they choose pleasure over that sense of belonging. But the longer it nags at them, the closer they get to 30 or even past 30, and the older they get, the sense of belonging becomes stronger and stronger. And so I think for that reason, that's exactly why I picked belonging is more important for women than sex because they do make that decision on a regular basis. So now that you know that, you can use it to your advantage. So make the woman that you're trying to date, make the woman that you're going for, make her feel like she belongs and you'll have her. Thanks a lot you guys. Good luck out there.