Hello and thank you for providing me with this opportunity to speak with you on the occasion of this OER Africa convening presentation. Unfortunately I couldn't be in Nairobi to be with you, but I was asked to say a few things from my perspective. OER Africa's overarching vision is a vibrant and sustainable African education systems and institutions that play a critical role in building and sustaining African societies and economies by producing the continent's future intellectual leaders through free and open development and sharing of common intellectual capital. Those are very lofty goals and based on these excerpts it's clear to me that an important part of OER Africa's mission is to help address the weakened state of Africa's tertiary education systems. This is not just about embedding OER in African tertiary educational systems. It's about OER Africa aspiring to play a transformative development role in Africa. So it's quite a big vision. The question is to what extent has it been able to play this transformative role from its inception to date? I think that it's been instrumental in evangelizing for OER and has achieved significant impact in reaching out to the higher education constituencies to sell the value added of OER. It's clear that the recognition of OER's value is visibly higher now than before OER Africa started early in the new millennium. Most recently the participation research initiative being undertaken in collaboration with a cohort of African universities has provided an opportunity for a deep dive, an opportunity to ground truth the theory of OER and learn critical lessons about what it really takes to lift the constraints to implementing OER in higher education in Africa. But obviously transforming Africa's tertiary institutions is a massive agenda that OER Africa cannot deliver on its own. In the area of OER remains a pioneer however it needs to connect more systematically and effectively with other Pan-African higher education initiatives that share this overarching vision I just spelled out and that are making progress in working with networks of universities to build capacity. I'll come back to this at the end of my presentation. I first interacted with OER Africa when I was asked to review a communication strategy that had been developed in 2009. So the second issue I'm going to address is the extent to which a communication strategy is important for OER in Africa or for any higher education initiative. One of the key lessons we've learned from decades of engagement with development is that you're only as effective as you are visible. Visibility has many dimensions which I won't go into in any detail but two dimensions are worth mentioning here. One of them is selling the OER concept to key stakeholders and the second one is delivering proof of concept which can then be used to develop further partnerships. In 2010 I reviewed the OER communication strategy and I posed six clusters of questions. The first cluster was whether there was a common understanding within OER Africa and in terms of communication and in terms of how OER Africa was integrated with its parent organization Saidi and I asked how central communication was to the work of the initiative. Secondly I asked how sustainable communication was when it relied very heavily on two people travelling to conferences and to talk to institutions delivering PowerPoint presentations, keynotes addresses and networking as a means of raising awareness of and creating demand for OER. How proven was the OER concept in Africa and to what extent should the strategy be focusing on case studies or stories which would showcase areas in which it was working for example in health OER. The third questions were related to OER Africa's messages. Were they the right ones? Do they clearly and effectively articulate OER Africa's unique selling points and were they appropriate or realistic? So there was a question there about OER saying what it intended to do as opposed to what it could actually prove it could do. Fourth, there was a question about the complexity of the OER Africa offering. It's not an easy thing to explain to people. Do the current materials communicate the core elements of the offering clearly and effectively? Was there a need to simplify and de-jagonize the language describing OER Africa? Fifth, OER Africa had gone through this iterative process of identifying its course stakeholders and potential partners which is extremely good practice as the first thing you need to do for any initiative that's predicated on engagement with others is to be clear about who you want to engage with. And this speaks, you know, this is as true for communication as it is for anything else. To what extent has this process enabled the mapping of key target audiences for the communication work and how rigorously has the strategy matched its products with the audience? And then the final sort of cluster of questions was which stem from the audience question. Should the website be the primary means of communication for OER Africa? Particularly given the fact that a lot of people don't have the bandwidth to access websites to the extent that they should. How much should be invested in the website and web platform as opposed to other communication tools and media of which there are many, including social media and many forms of engagement which don't necessarily rely on technology? How realistic is it to create a platform and expect others to own that platform and to populate it with content? This is a huge problem that most developers of websites and strategic communicators have which is that, you know, you expect ownership to transfer from yourselves to the audience but the audience don't necessarily engage with the platform in the same way that you envisage it. To what extent is it realistic to expect online communities to be self-organizing? And this was a hallmark of the OER Africa kind of offering. And how plausibly can attribution for enabling the work of others be claimed and measured? Can the gathering of statistics on the website be used to generalize into a results culture that sees OER harnessing evidence to inform its communication? Most of the challenges that arose and were implied by these questions seem to have been addressed by the OER Africa team either fully or to the extent possible. Of course a lot of this stuff is at the very technical and operational nature. OER Africa has made great strides in particular by its focus on health OER in demonstrating the power of OER and health being a particular sector where OER is gaining traction. Now I think there needs to be some sort of a shift in this effort. What should now take center stage is the effort to take OER beyond the realm of the converted integrated as a key tool for transforming higher education systems in Africa. For this to happen there is a need to elevate the pitch by sharing lessons of what OER Africa has learned so far with wider audiences. This convening clearly represents an important first step in such an effort. Additionally, however, there needs to be a purposive, well-crafted effort to cultivate partnerships with other actors in higher education in Africa. Some of these are intermediaries who can be critical in ensuring OER delivers on its promise. Others are funding higher education capacity and development. The third question I'd like to try and sort of address is the question of whether technology and innovation amount to the same thing. Policymakers tend to conflate the two things, but when it comes to higher education in Africa how useful is this conflation? If Africa is to revitalize its higher education sector will either technology or innovation suffice? My sense is that there's no either or in determining whether OER's transformative potential resides in technology or innovation. Technology is clearly hardwired into the concept of OER which identifies digital applications such as streamed video webcasts, webinars, podcasts and so on as key educational resources adding to the traditional materials that we commonly associate with higher education. The means of delivery of OER also heavily emphasize the need for reliable and affordable internet something that is now widely recognized in tertiary education as a fundamental condition for effective learning. How technology is applied in higher education makes the difference between whether it is innovative or simply ritualistic. Innovation applies as much to the content itself as to the means of communicating that content. The concern here is that policymakers are still at the stage where they fetishize technology as a solution to all of Africa's problems when in fact the real transformative potential of OER lies in the pedagogical innovations inherent in the concept. The proliferation of ICTs presents an unprecedented set of opportunities to deliver education to millions who in the past have been unable to benefit. Telecoms costs are falling dramatically as access to mobile phones approaches a saturation point. This can only be a good thing for many perspectives. However, more efforts needed to sell the innovative potential behind OER itself how it can revolutionize teaching and learning. At a time when there are existential questions being asked about the relevance and appropriateness of the pedagogy many African universities have borrowed from the Western Academy and are struggling to implement. The innovative power of OER has the potential to change the game and technology is an important part of the story but by no means the full extent of it. The last point I'd like to address is the role or roles that initiatives like OER Africa should play going forwards in transforming pedagogical practices in Africa's higher education sector. I think not being an expert on teaching and learning there's not so much I can say about methodologically or content wise what OER Africa needs to do to actually try and shape the higher education sector substantively. But what I can say is that at the beginning of the presentation I mentioned that OER Africa could not realistically take on the burden of transforming the tertiary education sector in Africa single-handedly and in my work I come across many new and emerging players in higher education in this ecosystem that OER Africa really needs to work with. There are a number of initiatives that typically involve networks of universities which do things like develop common curricula. For example there's PASGA, the Pan-African Social Governance Research Initiative which is working with at least 12 universities that I know of to develop a common curriculum and masters in research and public policy to try and fill the gap in this area. We have masters programs in disciplines such as economics but there is no masters program in research and public policy which A prepares students and graduates to engage in public policy and B prepares them to be potential PhD scholars. So this is something that PASGA is spearheading. It also works on issues such as research methods and has a whole training program for that. I see them as a potentially important partner for OER Africa. If anything, if the partnership is not already being pursued with them it should be. Another important higher education initiative is the public policy schools initiative which I think Vitz University is centrally involved in. It's funded by a number of prominent private donors and it seeks to build a caterer of future African scholars who will not only be very strong in terms of adding to the body of knowledge in social science but will also be practically engaged in addressing Africa's development challenges. Another initiative that I think PASGA, another initiative that I think that OER Africa should be engaged with is something called CARTA, C-A-R-T-A. CARTA is a doctoral training program that was conceived of and initiated by APHRC, the African Population Health Research Center, which is also based in Nairobi. It's been extremely successful. I was privileged to teach the policy influence module with another colleague last year and be exposed to PhD candidates who were almost finished. These are scientists and researchers who are of the highest caliber throughout Africa. I think that they would all benefit from great exposure to OER resources and to the whole OER philosophy and system. There's also the Pan-African University, which most of you would have heard about, which is a recently launched concept supported I think by the Swedes and others. There is ample evidence of a purposive effort to try and rebuild and revitalize the tertiary education system in Africa. There are a number of players based on the African continent with the Pan-African footprint who are working towards this endeavor. I strongly suggest that OER Africa needs to elevate its pitch. If the last 15 years have been a period of incubation, exploration, learning for OER in Africa, then these have been very successful years, but the time is now ripe to take things to a new level. OER Africa as a vehicle, I think, needs to be bigger, stronger and more engaged. In terms of its visibility as an entity, it needs to be able to be the same pitch as some of the other Pan-African initiatives. It needs to engage much more in strategic communication. It needs to also work much more closely on issues such as the uptake of research, which is a growing focus of a lot of universities now in Africa, sort of designing research processes to ensure that uptake is hardwired into the DNA of the research initiatives, making sure that at every stage policymakers are engaged with the research as it emerges. I think that OER as a concept can actually make a huge difference to research uptake. I think this is an area that requires a more muscular presence by OER Africa and a much deeper engagement and a much more visible engagement. Again, please accept my sincere apologies for not being able to be with you in person. Thank you very much for giving me this opportunity to present to you. Thank you.


This video will teach you how to install and run Home Assistant on Mac OS. There are two key components to Home Assistant, the Core and the Supervisor. Mostly all users will require both components to be installed in order to have a fully featured Home Assistant experience. It is possible to run the Home Assistant Core natively on Mac OS, however running Home Assistant without the Supervisor would not be recommended for most users. A better way to run Home Assistant on the Mac is to use UTM to create a virtual machine, which will allow Home Assistant to be run using Debian Linux. This tutorial will guide you through the process of configuring UTM and Debian Linux, which are both completely free to download and install. With that said, let's begin by downloading both of the necessary components. Follow the link on screen to visit the Debian download page. If you are using an Intel Mac, you should download the AMD64 package. If you are using a newer M processor, you will need the ARM64 package. If you are unsure which architecture your machine has, click the Apple logo in the top left hand corner of the screen and then click about this Mac. Here you will find the details of the chip that is inside your machine. Follow the link on screen to visit the UTM download page. Download UTM and unpack it into your applications folder. When Debian has finished downloading, go ahead and open UTM. We will now begin creating our Home Assistant virtual machine. First, create a new virtual machine and choose the virtualize option, then choose Linux. Next, click Rouse and navigate to the Debian file that you have just downloaded. You can leave the hardware and storage settings as default for now. You can change them at a later date if necessary. On the summary page, enter a name for your virtual machine, such as Home Assistant, and then click Save. From the main screen, right-click your newly added virtual machine in the left-hand sidebar. Right-click the display device and remove it. Then add a serial device and check that the mode is set to built-in terminal. Click on Network, and change the network mode to Bridged. This will allow your Debian virtual machine to connect to your network as if it was an independent computer with its own IP address. Once done, save the changes by clicking the Save button, and then close the dialog box. We will now begin the Debian installation process. Click the Play button to boot the virtual machine. When the boot menu loads, choose Install. Run through the various option screens, choosing the correct language and keyboard settings for your region. After configuring the keyboard, enter a host name of your choice, for example, Home Assistant. Enter your domain name. If you don't have a domain name, just leave it blank. Next, we will enter a password for the root login. We will also create a new user account. First, enter your full name. Then enter your desired username and password. These are the credentials that you will use to log into Debian. Now we can configure the virtual hard disk. We will choose guided partition for the entire disk. Next, we will choose all files in one partition. Then, choose to finish partitioning, and write the changes to disk. The base system will now be installed. We do not need to scan extra installation media. Now we need to choose our location, so that Debian can locate the most optimum archive mirror. You can choose whatever archive mirror you prefer. If in doubt, choose Debian.org. We can leave the HTTP proxy information blank. Choose whether or not you want to participate in the popularity contest. You can read the details here for further information. Now we have the opportunity to add the graphical user interface, but it is not needed for running a home assistant server, so we won't include it. I would recommend installing the SSH server and standard system utilities only. Once the installation is complete, ensure that you remove the ISO image from the virtual drive, then reboot the virtual machine. The virtual machine should now boot to the Debian login. Enter your username and password that you created during installation. Once at the command prompt, log in to the super user account. First, we will back up the network interfaces file, in case of any problems during the home assistant installation. Next, we will install all of the dependencies required. Now we can install Docker, the program that will manage our home assistant container. We also need to install OS agent, which will allow the home assistant supervisor to communicate with Debian. Follow the link on screen to open the OS agent download page. Scroll down and locate the .deb file for the latest release. Make sure you choose the correct file for your processor. Right click the link and copy the link address. We can download the package at the Debian command line by using the wget command. Type the command and then paste the link address copied from the OS agent download page. Once the package has downloaded, use the dpkg command to install it. Following the installation, we can test that OS agent is working correctly. The command should produce similar output as is shown on screen. Now we are ready to install home assistant. First, we will use the wget command to download the .deb package. Once it has downloaded, we will use the dpkg command to install it. You will need to select your machine type. Use QEMU ARM64 if you are using an M-series processor. Use QEMU X8664 if you are using an Intel processor. The home assistant server will begin, and you will be taken back to the Debian command prompt. Your machine IP address should be displayed, but you can also use the hostname command. Using a browser, navigate to your Debian IP address using the port 8123. This will take you to the home assistant onboarding screen. Congratulations! You have successfully installed home assistant on your Mac. Visit sitech.com forward slash home assistant for more tutorials like this.


Okay, so one thing I want to make clear is that it's not like a new story that that we in the West have are going to invent and then bring out to the world and show everybody here's the new way to do it you know we've been telling you here's the way to do it for a long time and well we were wrong but now we know what the thing is. So it's it's if it is new it's new for for us meaning us the dominant culture of this planet or the culture that dominates the planet it's new for in that context but it also draws on ancient roots and incorporates ways of being ways of seeing ways of thinking that older cultures that are still around have preserved with varying degrees of fidelity and that can offer to us right now if we approach them with humility rather than trying to appropriate what those cultures offer to fit it into our own attempt to construct an identity. So that's that's one thing I'd like to clarify that that you know new story maybe it's a useful shorthand but I want to explain that it's not something new on the face of the earth but it's rather more to bring something very ancient on this earth and to and and to say how would that what would a mass civilization look like if it was in touch with these ancient ways because I'm not advocating going back to the past either so yeah the new story is not something that we can articulate I mean I'm tempted to quote the famous Einstein quote that our problems will not be solved from the same level of thinking that created them we are not coming from the story of separation the story of control the story of domination the story of ascent over nature that so deeply infuses the thoughts and perceptions of anyone who's grown up in this culture from there we cannot even tell we cannot produce a new story that is not actually some retelling of the old story that's not how it works we're not going to sit down in a group and say okay let's think of what the new story is and then impose it on everybody else that's not where it comes from the first thing to understand is that this story exists outside of ourselves it's not something that we create it is a being or an archetype or a god that wants to be born on this earth and is calling us into service of it and revealing its face in little tiny glimpses these glimpses these revelations take the form of of an experience that you have that just is so amazing an experience of such deep connection an experience of cooperation an experience of of of participating in the regeneration of soil or of water the healing of land the healing of species the healing of each other it could be a deep spiritual experience or any reconnection with a layer of reality that's outside the current story and you have that experience and you think this isn't just some trick that that some diversion from grim reality this is a promise and it gives you hope hope being the premonition of a future i won't say the future as if there is one fixed future but it's a premonition of something that in a sense already exists outside of the linear time stream so once you've seen it then you can maybe describe it a little bit and you might try to weave like a whole utopian society based on that principle or something like that but you're going to get most of it wrong but what you have what you have what your treasure is is that glimpse you've seen it and you know it's real and maybe you meet somebody else who's seen it too and they say yeah you're not deluding yourself i know that this can happen i know that there's a path from a to b i know that there's a way to this beautiful world that i've caught a glimpse of i don't know what it is but i don't have to know all i need to know is the next step how do i know the next step the next step is comes through what calls to my care and maybe somebody else has seen another glimpse of it that's something different and and tells you their experience of being in that medicine ceremony or of being on that on that permaculture design course or whatever it was and you or of doing activism in a prison and or doing embodiment work i mean i i they might seem like something totally unrelated but this possibility that they've seen you recognize as yet that's part of the same thing that's part of the same story you may not be able to explain how you know that you may not be able to explain why you feel such a deep sense of alliance with this person who's work it is to liberate dolphins while your work is to i don't know um practice acupuncture like they seem so unrelated where maybe your work is to to uh find housing for homeless people like what is what do these two things have to do with each other but we sense we sense that we're all devoted to the same thing so that's how we come to know what i might call the new story or the more beautiful world our hearts know is possible it's another way i like to say it we get glimpses of it we get called into its service and with each step of service we maybe will be given more glimpses of it which come in the form of more experiences that say yeah you were right you're not crazy for following this path you're not crazy for thinking that if you just give your gifts in the most beautiful way that you'll somehow be taken care of that it's okay to do that you're not being irresponsible you'll get confirmation it doesn't mean that all of a sudden it's peaches and cream and that because you've stepped into the gift that you will be showered with monetary riches i mean no it may not be that but you will get confirmation in some form and you will also go through continued initiations that demolish the illusions that you took into it so the story reveals itself like a like this gigantic angelic being coming through the fog and sometimes the fog clears just enough to see one one facet of its of its wing or one little patch of its face and it's so beautiful that maybe if you saw the whole thing you would you would die or something you know it's just or actually what would happen is if you saw the whole thing you'd be you'd just have to turn away because it's painful a little bit to see what could be to see something that beautiful and then to know that the world is so far from that and to be aware of of just how much suffering there is how much wrongness there is how many children are being abused right now as we speak and the ones that even we don't recognize the abuse that they're that they're being you know walked into classrooms and subject to behavior management techniques and standardized tests and and minimum wage jobs and the whole thing and not to mention the ecological world so in contrast to that ugliness the beauty is almost too much to take so we're given as big a glimpse as we can handle and then that sustains us and we sustain each other by confirming that we're not crazy and by sharing the stories that showed us what was possible


Hey what's up everybody, it's Kevin Byer here, chilling with the princess. She just had some breakfast. We just wanted to remind everybody to practice social distancing at this time, stay home, stay safe. Want to make sure we ensure the safety of everyone around us, our loved ones, anybody that's maybe vulnerable to the COVID-19.   Me and my wife, we like to watch movies, TV shows, board games. We go outside, we play with our dogs and different things like that. So to all the medical professionals, I just want to do a quick shout out to you guys. Thank you for all your sacrifice and everything that you've been doing and helping us throughout this extraordinary unprecedented time right now. To all my Titans fans, man, just stay safe, stay home, do what we can, man, to stop this thing, man. Tighten up.


Welcome to the Knuckleheads of Liberty. And you said, who are they going to go after next? Well, that kind of brings us up to our next topic. And that was these 87,000 new IRS agents. Maybe we can get the visual for that one up again. So, you know, apparently the recent Inflation Reduction Act that was passed provides for another 87,000 IRS agents out there to go out there and audit people, I guess. And it does beg the question. I mean, there's only so many billionaires, I guess, you know? So, you would think you don't need 87,000 more agents to just focus on those people. So, and it sounds like the White House is being a little bit cagey, too, about whether or not these people are going to be going after people who don't make as much. And keep in mind, too, as we go into an inflationary spiral, you know, which we appear to be in, it may be that the average person is making over $100,000 pretty soon. That seems to be about where... I mean, my gosh, the average house in California, I think, is over $800,000 now. So, I mean, this is just absolutely insane land that we're being taken through, a lot by, you know, Democrat policies.  So, I just, you know, this is something where... You know, you could find yourself very easily in the crosshairs, I suppose. What do you guys think about this? Imagine an inflation reduction act, okay? Inflation reduction. Or when in truth, the piece of legislation inflates the number of agents, the IRS agents they're going to have. And it inflates their power to come after us. And it inflates the authority to come after us. And this is the Inflation Reduction Act. Like I said, these people are out of control and we've got to do something about it. We as voters, we as citizens of this great land, we have to do something about this otherwise you're going to lose our country. The IRS is already too powerful of a government agency.  They're going to audit me, they're going to come after me. What, what, what? You read it and you're already terrified. Just because they say IRS and now they're expanding their powers and authority? That's what they're doing. They're expanding their authority. So what's next? Well, Leon, thank goodness they only called it the Reduction Act and they didn't just call it the war on inflation because then we know we'd all be doomed if that were the case. Just never into inflation. Well, we know they have a war on taxpayers because that's the reason their budgets were limited before.  They weren't going after the rich. They were abusing poor taxpayers so they limited their budgets. So what they do, they went after poor taxpayers again. And now they're going to give them more agents and more money to go after people. The people at the top can want anything they want, but the people at the bottom are going to go after what makes their job, what hits their performance goals. You're not going to hit your performance goals if you're going after billionaires and millionaires. You can fight back. You're going to hit your performance goals by going after the people who can't. That's just the way the system is set up. In order to hit your goals, just like it's like a traffic cop, there's essentially no different than a traffic cop who has to meet their daily or monthly quota. And where's your monthly quota going to get set out? Parked outside of a school right around right before and right after school runs out, right? That's where you're going to park.  And it's no different. They're going to go after the low-hanging fruit. The low-hanging fruit is gig workers, which you've already seen them attack, freelancers, anybody who's small business owners, that's where they're going after. And you and me go on sending money to each other through Vimo. They've already set that up where they're tracking that. So they've already put the systems in place to attack poor and working-class people, and they're setting up the enforcement arm right now. But the old point is at the end of the day, James, and we are American citizens, okay? And we have certain amount of rights granted by God and granted by our Constitution, okay? And we have to protect ourselves against these people, okay? We have to use the courts or whatever we have to do, but we have to protect ourselves against it. Life, liberty, and the pursuit of happiness always.


Okay, so thank you for coming. So I'm Clement Verna, I'm working on Fedora infrastructure and I'm maintaining the container build system and today with Rado, we're going to talk to you about container testing with a library that Rado maintains, Konu. So my name is Rado Butenac, I'm maintaining Konu, I'm Clement, working for Fedora, and I'm also working in the user space containerization team in Red Hat. So today, how do we test containers? So we are living in the edge of CI, CD, all applications have unit tests, integration tests, and we have like continuous delivery, continuous deployment. But we are not really have a good and an easy way, a good framework to test containers that we are building and running on OpenShift Kubernetes as a black box. So that's the problem that Konu is trying to solve. And we have like really two main use case, it's testing standalone application, so make it easy to just spin a container and run some tests against this container. But also being able to test orchestrated application when you can actually bring up a cluster of containers and test interaction between each of your services. So here Konu comes to the way, and Konu is simple, a Python API for containers, and the word containers is important because it supports many container engines, also for standalone containers and orchestrated engines, and also provides helpful functions for testing containers. So I think the best way to show the demo. Yeah, we don't have many slides, it's mostly some demos. It's okay, the phone size. So I've prepared to turn on the book for this. So let's start with some Docker example. So it's as simple as import Docker backend from Konu. Here I'm just simply creating it. And I want to work with the NGNX image, so I will create the image instance. I already cached this image, so it's already downloaded. So I can inspect. Here is the output of the inspect. For this we are using Docker. So here I want to run this image as a container. So let's try. And we can verify if the container is running, and also get some useful information about the container, like IP address, ports, container name. And when we are finished with our testing, we can stop the container and verify that it's not running anymore. So this was very simple use case just to play with the Docker. And let's move to a more advanced example, maybe. So here I will use all, which I already pulled. And I will start the simple HTTP server here. So let's run it. So I can see that the server is running at the port 8,000. So I mapped the port 8,000 to the host also. And now I can use the HTTP request function to actually make a request on the container and verify the status of the request. And I can see that it was successful and show the content of the actual page that is served by the server. So we can see that it's just a simple list of directories. So we can make another request. That is on the specific path. Here is ATC. Again, verify that it's OK. And see that this folder is actually there in the content of the request. And this is the same step as we did before. So stop the container and verify that it's not running anymore. OK. So this was the example of the standalone image. But usually we want to test if our images are working in the orchestrated environment, like Kubernetes and OpenShift. So for this, Konu has also Kubernetes and OpenShift backend. So the workflow is the same as with Docker backend. So I will just create instance of Kubernetes backend. And in this example, I will combine these two. So I will also use Docker backend in the same way as in the previous example. So I will just don't want the OpenShift, the whole OpenShift image. And right now I can really easily try if my image is running in the Kubernetes with this method that is running in POT. We just specify just namespace. So now I can see that the POT, the whole OpenShift is starting. So I can verify if it's ready. And yes, it's ready now. And I can see some useful information about the POT. And when I'm finished with testing, I can easily delete it from the cluster and verify that it's already in the terminating state. So this is also the simple example of using the Kubernetes. But there is, for example, usually we want to use deployments in Kubernetes. So Konu has also support for this. And here I will do the same steps. I will just initialize the backend. And here I will use this simple template, or deployment template, and create the deployment object from this template. So let's run it. Okay, so I can see that there's a deployment creating and it's not ready yet. So I can, here I can get the status in the adjacent format. But anyway, it's ready and now it's ready. So all POTs for this deployment are ready now. And you can easily, again, delete the deployment. So this was for Kubernetes. And there is also support for OpenShift. So let's look at it. The beginning is just the same as the other backends. And here I'm just going to deploy this image. I'm using MariaDB. With MariaDB I need to specify some environment variables. Like this one is required. It's just root password. And I specify the project. So it's first import the image into the OpenShift internal registry. And then it creates new app. So I will verify if the POTs are ready. And yes, POTs are ready. Right now I can get walks from the deployment. And I can see that there was like MariaDB deployment. Don't be scared. It's like a full walk on this. But it's just all deployment of MariaDB. Okay. I can verify the status of my cluster and clean the cluster from the objects that were created by label of my app. So now I'm deleting all objects with label of my app. So that was like really easy way how to just try your image and deploy it in OpenShift. And verify that it works properly. But sometimes we want to get advantage of using source to I in OpenShift. So I prepared example also for this. So just check the status. So here I'm using the method create new app from source. And only difference is that I'm also specifying the source, which is actually the GitHub repo with my app. In this case it's Django. And I'm using source to I image of Python 3.6. So let's deploy it. So this is the same process. The image is imported. And the app is being created. So I can check the status. And I see that the build is running. And the deployment is actually... So now it's not ready yet. I need to wait a little bit. It's ready now. So the app is running in this spot. And the same way I can just clean my OpenShift cluster from the object that I deployed. So this was the quick demo. Like what you can do with OpenShift. But there is more things that you can do. And you can find it in our upstream repository, which is user.com. If you want to see... It's in examples here in docs. And there is like many more examples of how you can take advantage of Konu and test your containers with it. So right now the project is in the space that we would like to hear your feedback, actually. So if you would run some tests and try to write tests for your container, we would be happy if you provide us some feedback or some feature requests. So that would be great. Okay. This was for the demo. So in Fedora infrastructure we have started to use Konu to test our services. Because in particular, BODY, which is the Fedora update system, this is a very central service in our infrastructure that talks with the build system, talks also with the result of the CI that we run on the packages. So it's relatively important when we do our tests not to do only unit tests, but we wanted to be able to have integration tests and see how the interaction between all those services are working. So if you want to have an example of how we use Konu, the nice thing of Konu also is all the helper functions that it provides. And it provides a very nice interface to PyTest. So you can very easily create fixtures that are starting containers. And that's what we have in BODY examples. So if you want to have a look at what we have done, I've put a link to a very simple example. It's the PyTest fixtures that will start PostgreSQL container. And then you can use this container in Overtest to run your tests. That's very easy to use and quite convenient. We are also starting to build the CI pipeline for our containers. So in Fedora, we are building the Fedora-based image, but we are also building other services like PostgreSQL, MariaDB, or Source2Image images. And we would like to test the same way we are running CI on RPM packages. We would like to run CI on those containers and release those containers in function of the test results we have. So we are using the same framework that the RPM packages CI is using, but we are using Konu to be able to run tests and really as a black box testing, we start the image and we will just run a few tests to check if the container is behaving correctly. And I think that's it. So if you have any questions, we are happy to answer. So the question was can you use Konu to write tests that will be able to run on multiple back-ends, so maybe locally you want to run on Docker. So it might be doable using the fixtures in PyTest, so most of your test case would be generic and you would have a fixture per back-end, so you could actually choose, in function of the back-end, you would like to run, you could just swap the fixture. Yeah, we don't have a use case like that, but that's how I would try to do it. Any other questions? Yes, so the question was are there any ways of cleaning the containers in case of exceptions? So the question is, is there any plan to support container on AWS? And if it runs like, actually that might be a good feature request, as you said. So currently, I don't think there is any work on that, but there could be a valid use case. Any other questions? So the question was if you have already a configuration for your OpenShift cluster, can you feed it to Konu and manage and just reuse the same cluster configuration that you have that you deployed to run your test on? And if you can do with the specific objects from template in Konu? Yeah, I have a template that creates templates. Okay, and if you can individually work with these ports? Yeah, that's the good question. I think there is no support for this right now. But you can list your posts. Yeah, you can do this. You can see what objects you have right now and get the list of that. So technically you can do this, but in this one more step in between. For the use case where Docker Compose are used to set up developer environments, could you replace Docker Compose for Konu? So the question was, in the use case of a developer environment, can you replace, could you use Konu to replace Docker Compose using the podman backend? I think that could be. So the answer was that that could be done, but maybe Ansible is a better alternative for that. Okay, one more question? Thank you very much.


The depths that some people in this country will go to just for attention is genuinely Disturbing and depressing. Nonetheless, we have a situation where somebody who trolled AOC by literally filming himself sexually harassing her I'm of course talking about right-wing provocateur Alec Stein Well, he's now suing her because after he sexually harassed her and filmed himself doing so She blocked him on Twitter and now he's taking her to court alleging that his First Amendment rights Have been violated now for those of you who don't remember the story back in July of 2022 AOC posted this on Twitter about the incident saying I posted about a deeply disgusting incident that happened today on the Capitol steps But took it down because it's clearly someone seeking extremist fame It's just a bummer to work in an institution that openly allowed this but talking about only invites more just really sad She continues. Here's the video. He posted of the incident I was actually walking over to deck in because if no one will protect us then I'll do it myself But I needed to catch a vote more than a case today. Now. Here's the video that she shared Oh, I love it AOC That right there is textbook sexual harassment and he's doing it for attention and clout and AOC Isn't the only person who he has harassed. He showed up to the I believe headquarters of barstool sports Calling out Dave Portnoy and he brought some guy in I think a diaper and he does these things to illicit responses and gain notoriety So AOC what she was referring to there is his desire to get attention So what she did is she responded properly to a troll by trying not to feed the troll and she just blocked him But in this instance well since she is a public figure He's claiming that his first amendment rights have been violated and he's now suing her insider reports in the suit Stein claims that Ocasio-Cortez was actually flattered by his comments I'm sure supposedly evidenced by her flashing a peace sign at him But blocked him once she realized he was not a political ally The lawsuit also provides a screenshot from Stein's account showing that he was blocked Stein's lawyer requests that he immediately be unblocked from the AOC Twitter account Ocasio-Cortez's personal account which the suit describes as her de facto official account now Let's be very clear about this. Alec Stein is suing her so he can get more attention by talking about this right now Unfortunately, we're giving him exactly what he wants and by looking at his video reacting to his video in a negative way back in 2022 we all gave him exactly what he wants because there are some grifters online who they thrive on Negative engagement because even if it is the case that most of the people who react to them are reacting in a negative way That's still attention nonetheless and that still helps him build up his name recognition get his name out there And now he has a show on the blaze TV. So by him sexually harassing AOC and subsequently suing her We have to be real about the fact that this is a troll who is trying to get attention Having said that though There could be merit to his case because as insider continues the suit Knight First Amendment Institute versus Donald J. Trump In which a federal judge ruled in 2018 that Trump had violated the first amendment by blocking his critics on Twitter via his Personal real Donald Trump account the ruling established that personal accounts can turn into a governmental one if it becomes an organ of official business However, another suit Campbell v. Reich Maintained that certain accounts run by government officials even those that sometimes tweet about official government proceedings can still be considered Personal and therefore exempt from this rule So it seems as if there is a lot of legal gray area here and the parameters haven't really been established yet But because of the Knight First Amendment Institute v. Real Donald Trump case It does seem as if just as a general rule Politicians since they are public figures who represent the US government should not block their critics however, is there a difference between blocking a critic and Blocking somebody who is harassing you because in real life you can't take legal action against somebody who's criticizing you on the streets However, if that individual is following you around and screaming at you and harassing you you can call the cops You can get a restraining order on that individual. So is social media the same thing? We've also seen how when protesters show up to the offices of politicians. They can get arrested. So is Twitter tantamount to Public protest does harassment apply? These are open questions that don't actually have legal answers to you can make a moral argument against these things But it's difficult to say legally what exactly is going to happen now AOC actually was sued back in 2019 for blocking somebody who criticized her and in this instance It was very clear that she was not being harassed by this individual so she ended up settling and Apologizing to the individual who she blocked which is a former Democratic state lawmaker in New York who criticized her for calling Trump's migrant detention facilities Concentration camps so according to a court that violated his first amendment, right? That was legitimate political criticism, even if you and I disagree with it. So the question is What's gonna happen with this case and it's really difficult to say now AOC Has talked about this before and she's defended her reasoning for blocking individuals and she says that Harassment is not speech that she has to put up with even though she's a government official In fact, here's what she said specifically. I have 5.2 million followers less than 20 accounts are blocked for ongoing harassment Zero of them are my constituents Harassment is not a viewpoint some accounts like the Daily Caller posted fake nude photos of me and abused my comments to spread it No one is entitled to abuse. She added people are free to speak whatever classist racist false Misogynistic bigoted comments. They'd like they do not have the right to force others to endure their harassment and abuse So the legal question is does harassment constitute protected political speech? so What Alex Dine did there was obviously harassment and I'm assuming that he subsequently took to Twitter to harass her and brag About sexually harassing her in public. In fact, I think he did. I'm pretty sure I remember that but Is he entitled to view her posts given that one he harassed her That's not just legitimate political criticism and two. He's not a constituent of representative Acasio-Cortez and three Well, he's very clearly just trying to get attention. Is it the case that his First Amendment rights have been violated by AOC? because if she was forced to Unblock somebody who she blocked before will the same be true here Well, I think that this case is going to determine legally if there is a distinction between political criticism and harassment and I'm not qualified to make that legal judgment another interesting question is is an alternative remedy like muting them Sufficient. I mean, these are all questions that will be answered by this case But one thing is for sure regardless of the merit of this case It's clear that Alex Stein is a troll and a provocateur and this is nothing more than his lame attempt at getting attention But it is a complicated legal question about whether or not lawmakers Blocking individuals online is a violation of the First Amendment We've seen in limited instances that that does indeed seem to be the case But if it's harassment does that change anything? Well, I guess we'll find out because of this case But either way regardless of what happens in this case Understand that Alex Stein is a troll and is not to be taken seriously by anyone You


Welcome to the next lecture on multi-phase flows. What I want to do is before I start just want to summarize what we have done so far in the last 4 lectures or so in this class and to tell you what is going to happen at least in the next 4 lectures okay and you will have some idea about what is in store for you. So what we have done is use the fact that all of you have some basic knowledge of fluid mechanics okay and we have used that and we did not bother to you know derive the Navier-Stokes equations or anything. We just said that you all know fluid mechanics and then we decided to analyze a specific 2 phase flow problem okay and the thing that we respected ourselves to is laminar 2 phase flow. Now I just want to emphasize that as far as the entire course is concerned we are going to mainly be looking at laminar flows. We are not going to be looking at turbulence at all because there is a completely different ball game. You need to analyze situations using computationally intensive methods. The focus here is not so much on computationally intensive methods but on getting a good physical understanding. So if you were interested in doing a turbulent flow analysis of a 2 phase flow problem what you would be doing is looking at doing direct numerical simulations, doing computational fluid dynamics okay. So we are not going to be doing all that. So the reason I am telling you this is tomorrow when you are reading papers you will see that there are people who are doing fluid mechanics who are using those kinds of principles. You will see people who are not using CFD but they are using the kind of methods that we are talking about. But the idea is for you to know the differences and see if we can learn from one technique, one approach and how we can apply it to another. Similarly you are doing turbulence how I can use ideas from that method to this. So that is something which you should be clear about and that is something which not only as far as this course is concerned for anything that you are doing. You are going to be looking at working on a particular problem. You are working on an area which is maybe reaction engineering or fluid mechanics whatever. There would be so many things in the same area and you should be able to know what the similarities are and dissimilarities are between what you are doing and what somebody else is doing. Because that is the only way you can become more clear in your concepts okay. So that is what I am trying to tell you now is that what we are doing is mainly non CFD approach okay. But then that gives you a lot of insight tomorrow when you want to do computational fluid dynamics. So that is the way you have to take this course okay. So what we did is we looked at stratified flow towards the end you have to do the core annular flow and we want you to basically work out couple of problems. The idea is normally what you would think when I am pumping 2 different liquids in a tube if I pump 2 liquids with let us say the flow rates of the 2 liquids is Q1 and Q2. The volume fraction which is going to be occupied by each of the liquids okay is not going to be given by the ratio of Q1 by Q2 or the volume ratio okay. So that is one of the things which we wanted you to understand by the 2 examples that we did the stratified flow example as well as the core annular flow example okay. So that is the reason why we wanted you to calculate the velocity profile. We wanted you to calculate the hold up. The hold up is the volume ratio. So let us say V1 and V2 are the volumes occupied inside the channel by each fluid. We want you to be clear that V1 by V2 is not equal to Q1 by Q2 and that would be something which is normally the thing. I am pumping in 2 liquids with the same flow rate. So you would expect that half of the tube is occupied by 1 fluid half by the other but those of you who have done the assignment will realize that this is going to be decided by the ratio of the viscosities okay. And the reason why the other parameters do not come into the picture is because we are assuming that we are in the lower Reynolds number regime so that the density does not show up okay. So that is one thing which I wanted you would take from the lectures that we have seen so far okay. Now what we want to do is we want to do things in a slightly more formal setting we want to extend. We have assumed that the interface is not changing in size in shape as far as the position is concerned. So we want to get to the position where we are able to incorporate the changes of the interface.  So the theory is going to basically focus on deriving the Euler's acceleration formula which I have already seen which then we talk about the Reynolds transport theorem which is basically a conservation principle okay. And then we will see how we can generalize some of the boundary conditions that you saw earlier regarding the pressure jump across the curved interface. When you have a curved interface in a core annular flow the surface tension basically helps you evaluate what the change in the pressure is. You need to know the curvature you need to know the surface tension and you can estimate what the pressure difference is. So now what we want to do is we want to generalize that to the case where there is flow. So that is what we are going to do and then we start working out some problems okay. So next 3-4 lectures is going to be basically on trying to establish the thing on a firm theoretical footing. Some of it may be repetitive to what you already seen but it is always good to you know revise and revisit some things and then go forward. So let us look at the theoretical basis of let us say fluid mechanics okay not being very careful with the English here but it is okay. So normally 2 approaches you are already familiar with okay which you have seen in the past and the 2 approaches used in tackling flow problems. The first one is the Eulerian approach and the second one is the Lagrangian approach okay. So what is the difference between these 2 approaches? What we do in the Eulerian approaches? We are focusing our attention on a fixed region in space okay and we are trying to understand how things parameters like velocity, temperature, etc. change in that fixed region in space. So now this region in space can be very infinitesimal, it can be very small, it could be just a point and supposing you actually were to measure temperature at a particular point in a keep a thermo at a point, it is going to measure change in temperature. So you will get a temperature as a function of time but that is at a fixed position. So what you are doing is you are basically using an Eulerian approach whereas the Lagrangian approach is one where what we are doing is we are not looking at a fixed region in space but we are looking at a fixed particle or a fixed collection of molecules or a fixed molecule because it is a fluid flow problem the molecule is going to move. So in order for you to be able to track the change in the temperature you need to be able to have a probe which is tagged on to the molecule okay. If you have a probe, if you have a thermocouple which is able to sense the temperature of the molecule as the molecule moves you will be able to actually measure the temperature. So then you are actually doing a Lagrangian approach okay but now what is happening is this probe is going to occupy different regions in space but it is tracking the same molecule okay or same particle. So there is a difference between these two approaches. Now the reason why we need to be clear about this is because most of your fundamental laws that you have come across earlier like your conservation of mass, conservation of energy you have are used to those laws in the framework of the Lagrangian approach okay whereas because when you talk about mass cannot be created, mass cannot be destroyed you are talking about you know the stock piece same sort of molecules is going to remain. So you are talking about fixed set of particles fixed you know object whereas what you are talking about here is fluid mechanics where things are going to be flowing okay it does not really and what you are interested in is how is the velocity at a particular point. So you need to understand the difference between these two approaches because what we want to do is we want to see how we can extend the fundamental laws like Newton's law of motion where you say force is equals rate of change of momentum okay we want to see how because that is for a fixed particle we want to see how I can extend that to a fixed region in space because that is what we are interested in we want to find out rate of change of momentum and how that depends upon the forces etc in a fixed region in space okay. In fluid mechanics since you have a fluid flow problem we are so normally what happens here is in a fluid flow problem you know I just put a diverging channel because I am going to use this later on you will have you know let us say fluid moving from left to right. If you focus at a particular point here this particular point is going to be occupied by different molecules at different times because there is continuous flow. So if you want to measure the temperature here you will be measuring the temperature of different molecules but at the fixed point okay. So if we have a probe at let us say A okay this measures the property different molecules but at one point. So because the probe is here my thermocouple is right here okay because of the fluid flow it measures the average temperature of all these particles there. Now this is what approach is this? This is the Eulerian approach and this is what as an experimentalist you would be doing you would be measuring a fixed point in your reactor or your heat exchanger or whatever it is whereas in if the probe moves with the fluid and is attached to a molecule okay or a particle then the probe measures changes of the property of the particle okay which moves around in the fluid and this is your Lagrangian approach and the fact is what we are really not interested in what is going to happen to the temperature of the particle. So if you want to have a probe here stuck to this particle maybe some kind of a radioactive dye or something and you want to try to find out how the concentration is changing it moves. We really want to find out what is happening inside my system. Once it goes outside my system it may not be of interest to us. So there is no point in trying to talk about changes of the material particle because you are really interested in what is happening inside your heat exchanger distillation column reactor whatever it is okay. So we need to therefore go to using only the Eulerian approach okay but what is so special about the Eulerian approach the fact that to repeat most of the laws conservation laws are in the framework of the Lagrangian approach and we want to know how to relate changes in the Lagrangian approach to changes in the Eulerian approach that is the idea okay and once we know once we are able to do that then we can go back to solving the problems. In fact we have already seen this but maybe in a different context or in a different framework so we will just try to relate that. So just to summarize most fundamental laws are in the Lagrangian framework okay and we want to apply these laws in the Eulerian framework. Now I will go back to this problem of flow in a diverging channel okay to basically point out what the difference is between these two approaches okay just to clarify things. So let us go back to this problem in a diverging channel. Let us look at steady flow to make my life simple what I am going to do is I am going to assume that the flow is uniform across the cross section okay. So this is a rectangular channel which is extending to infinity outside the plane of my board and just to illustrate the idea okay. So I am going to say and I am going to put slightly smaller arrows here. So the length of the arrow basically is reflecting the magnitude of the velocity okay and what I am trying to tell you here is that the magnitude of the velocity is uniform here. So the velocity is not changing in the direction perpendicular to the flow. So if this is my flow direction is x and this is y direction does not change in the y direction the velocity does not change in the y direction everywhere. So since the channel is diverging one of the things we do expect is that the velocity is going to decrease as you go along the flow okay. So you have a uniform velocity here you have uniform here but the value of the velocity here is going to be different from the value of the velocity here. So if you want to call this point this section 1 and this section 2 and if you are talking about liquids then we all know from the macroscopic continuity equation that rho 1 A1 V1 equals rho 2 A2 V2 okay and we are talking about liquids the densities do not change you will have A1 by A2 equals V2 by V1. So if A1 is lower than A2 V2 has to be lower than V1 and that is the basically is going to decelerate. So now I am going to ask you the following question supposing I were to have a probe which is going to measure the velocity at this point okay you keep your pitot tube or you have some device by which you are trying to measure the velocity and if you were to measure the velocity here what would be the value of the velocity which your probe is going to measure? It is going to be V1 and this V1 is not going to change with time right because I am basically assuming that my flow is steady. Steady means at a fixed point in space the V1 does not change with time okay. So as far as my fixed probe is concerned so if we have a fixed probe V1 measured does not change with time and this is my Eulerian approach that is what it will tell us right. This is in the framework but now what is happening to the actual liquid particle which is moving from here to here. Liquid particle supposing you were to actually track a liquid molecule it has a high velocity here it has a lower velocity here. So now the molecule is actually decelerating okay. So the particle per se is having a change in the velocity. So if you were to actually sit on a particular particle you will find that you are slowing down clearly because V2 is lower than V1 okay. So in the Lagrangian framework the velocity of the particle will slow down okay since yeah we have a diverging channel okay. So it may appear to you like there is some kind of an inconsistency you are looking at a particular point things are steady things are not changing and whereas if you were to actually go but the idea is that you are using 2 different frameworks 2 different reference frames for doing your analysis. So depending upon the frame of analysis that you are working in you will have 2 different observations. So what we want to do is we want to see if we can actually relate these 2 things okay and that is basically our thing and we are going to extend this to a macroscopic region and that is what Reynolds transport theorem is. So first we will do it for a very simple case which is for an infinite simul. So let us relate the observations using these approaches for infinite simul region in space basically what I mean is point in space occupied by an infinitesimally small object okay. So basically I am not talking about I am talking about points I am just trying to make relate changes in points to changes in infinitesimally small particles that is the idea okay. Now just to try to make things clear let us talk about a scalar quantity like temperature. Now because temperature is something which you can measure using a thermocouple okay. So now let us focus on the temperature in the system. So now if clearly in the most general situation the temperature in that particular system is going to vary with the spatial coordinates x, y, z okay and also time if you have an unsteady state situation okay. So now temperature is can be written as temperature of x, y, z and t okay. This is the most general variation of temperature that you can see spatially as well as temporally okay. You suppose have your probe suppose you can think of an ingenious probe which is tagged on to a particular particle okay and it is moving around the fluid. This particular probe is going to change its position is going to move around right. So what this means is the spatial coordinates x, y and z are not fixed anymore. They are also going to be changing because now if you want to use a Lagrangian approach if you were to actually try to change to find out how the temperature is changing of this particle you are going to measure the temperature change not only as a function of time but also as a function of position okay. So in the Lagrangian approach if the probe is tagged to a particle the temperature that is measured is going to be depending on x, y and z which change with time because the particle keeps moving and it also has retains this explicit dependency on time okay. So what we want to do is we want to basically talk in terms of rates of change of the temperature that you are going to observe from your reading okay. So if you have a temperature probe which is giving you data signals you will be getting temperature as a function of time and position okay but for the same particle. So this particular change of temperature with time the rate of change of temperature with time is going to be what is called a material derivative because I am focusing on a single particle okay. So dt by dt is nothing but the total derivative. So this is rate of change of temperature with time of a fixed particle okay and I am using this particular symbol capital D you will hear this kind of nomenclature when you are reading books some people call this material derivative some people call it substantial derivative. This is basically taking into account the changes of temperature with respect to both position and time okay. So in this framework dt by dt is nothing but dt by dt which is the total derivative. In mathematics you would have come across you know partial derivative total derivative okay. So this is the total derivative. So I am just going to go back to calculus and establish this relationship between Eulerian and Lagrangian frameworks okay without really complicating the issue too much. This tells me how in the for the particle the temperature changes time and now I need to only differentiate that expression of this functional dependency okay and keep in mind that the spatial position also are functions of time. So now when I want to differentiate this thing find the total derivative I will get dt by dt as partial derivative of t with respect to x times dx by dt plus dt by dy times dy by dt plus dt by dz multiplied by dz by dt plus dt by dt okay. So all I have done is I have just differentiated that expression and I am differentiating that with respect to time and I am telling you that I am incorporating the dependency of x on time explicitly to take into account for the fact that the spatial position is changing with time and when you are actually using the Eulerian frame of reference what are you doing? You are fixing yourself at a point and you are trying to measure the rate of change of temperature at a fixed point okay and that is the partial derivative with respect to time of the object that you are interested in which in this case is temperature okay. So what I am trying to tell you is that this last term here represents the Eulerian derivative and that is how that is the rate of change of temperature with the fixed probe would measure. This is the rate of change of temperature which are variable probe which is moving with a particular particle is going to measure and basically this equation which is nothing but which has come from calculus okay which is the relationship between total derivative and partial derivative is basically the relationship between my Lagrangian framework and my Eulerian framework okay. So what I am trying to tell you here is that this total derivative is what I measured in the Lagrangian approach this is what I measure in the Eulerian approach and all I have done is just use calculus nothing else okay. So now what I like to do is write this in a slightly more general form which is this velocity vector is nothing but dx by dt dy by dt and dz by dt right the 3 components of velocity I can write gradient of temperature as dt by dx this is also a vector dt by dy dt by dz. I am going to write these first 3 terms on the right hand side in a compact way as v dot del t okay and what that relationship gives me now is dt by dt equals v dot del t plus dt by dt okay. So this is the Lagrangian derivative or the substantial derivative or the material derivative how does temperature of a particular particle of a particular material change with time this is how does temperature at a fixed point changes with time okay and the relationship between these 2 is actually given by this okay and I can write this for any quantity that I want. In fact I can write this for velocity this becomes dv by dt equals v dot del v plus dx by dt. I did do this for velocity at the beginning because velocity is a vector and then at some of you may not have been comfortable with gradient of a vector. So I just did it for temperature and having done it for temperature I have just written it for velocity okay. We will see how gradients of vectors are defined later on in the course and this is something which you are all familiar with and this is called the Euler's acceleration formula. Going back this problem of diverging channel where we spoke about the fact that the velocity is actually going to decrease as the particle moves one of the things we want to do is we want to see how we can apply the acceleration formula here to that particular system okay and our flow was steady. So our flow is steady what that means is the partial derivative with respect to time is going to be 0 okay. So this is 0 so dv by dt is 0 since flow is steady and what about dv by dt? dv by dt is the rate of change of velocity of a particle and we know that it is not 0 because it is decelerating. The particle is actually slowing down so this is not 0 but what is the value of this dv by dt it is v dot del v and if you for a very simple system that we have where we have velocity only in one direction in the flow direction vx which is actually changing in x direction if you about to evaluate this expression this is going to be given by vx dvx by dx. So that tells you how the acceleration is for the particle okay and you can find out if you know how the area is changing you can actually calculate how this velocity is changing with x and you can actually calculate this. So the deceleration of the particle so I just wanted to illustrate clearly that this is the relationship between the Lagrangian approach and the Eulerian approach. This is the time derivative which you measure at a fixed point which is Eulerian framework. This is the time derivative you measure when you are tracking a particle and this is how they are related okay. What I have done here is for a small at a particular point I am just assuming the temperature is a function of x, y, z I am trying to relate changes of temperature at a point to changes of temperature occupied by a molecule at that point. An infinitesimal mass, infinitesimal volume our objective next is to generalize this to a macroscopic system okay. So the same conservation so when I do this when I actually try to relate the Eulerian and the Lagrangian frameworks for a macroscopic region I get what is called the Reynolds transport theorem okay. So extending this from an infinitesimal volume to a finite volume in space P obtain the Reynolds transport theorem. What I will do is tomorrow and the next class is talk about the derivation of the Reynolds transport theorem. Try and show to you that you have already seen the Reynolds transport theorem in a different form. It is just that we are having a slightly different way of looking at the problem okay. So you have all seen Reynolds transport theorem in some other avatar. You are going to see this in this new avatar now. Then we will apply it to deriving the continuity equation the Navier-Stokes equations that you are all familiar with which you have been using. So once that is established then we go back to formulating the boundary conditions and stuff like that. But let me since I do seem to have a little bit of time let me just add a few more things so that I can do things in a more relaxed way tomorrow. So just to I am just going to call this RTT Reynolds transport theorem. I want to just introduce 3 concepts which are very simple and so it makes my life easy tomorrow. Control volume is nothing but a fixed region in space okay. It can be of any arbitrary step but it is not changing it is a fixed region. So it is analogous to my infinitesimal point okay. This is space. The boundary of this control volume which is going to actually demarcate the volume from the environment is what I call the control surface okay. Surface is the boundary of the control volume okay. And then we will talk about this other thing which is control mass. Control mass is a collection of particles, collection of molecules which have the same mass okay. So this is a collection of material particles. So this has a fixed mass but it can move around in space okay. So just to tell you what the analogs are what we have just seen this is at a fixed point okay that is your when you are looking at a fixed volume you are doing a Eulerian approach when you are looking at a control mass which is moving around you are actually looking at the Lagrangian approach okay. So the mass can change shape okay it can change size but then it is not in the fixed region in space it is moving around with the flow. So what we want to do is we want to try and extend this particular relationship that we have got for an infinitesimal particle okay occupying an infinitesimal region in space to a finite size control volume and that is going to be the topic tomorrow and that would basically be the basis. In fact if you understand Reynolds transport theorem if you can actually apply Reynolds what you would be doing as an engineer is you would be applying Reynolds transport theorem to different systems and depending on the system the final form of the Reynolds transport theorem is going to be different. So what we will do is just give you the general form of the Reynolds transport theorem and then depending on the particular system you are going to be analyzing you will be looking at different final versions of the Reynolds transport theorem.


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If you want to be successful in business, there's basically three things that you need. You need people, you need product, and you need processes. First of all, most important is people that includes clients, your team, your employees, partners, even mentors. If you don't have people, then you won't have a business. And that's important, but also talk about products, right? You need to have a good product. You need to have a product that is different, that offers something unique that other products don't do, that don't offer. Or you need to add a little bit of something extra that other people are doing. Basically, you're filling a gap or filling a empty space in the market. Let's talk about processes. You need to have good processes. So, for example, when you make the product, how are you making it? How do you make it in a way that's going to be consistent and how are you going to send it to your customers? After the customer receives them, how will you know that they will use it and how will you know that they're going to have satisfaction after they get the product?