Let's welcome Andres Cidel and let's find something new about how to create the production environments, secure production environments, using Docker. Hello. Can you hear me? Yes? Okay. Thanks for coming. First of all, as my mate said, I'm going to talk about Docker security environments. And I'm going to give you some best practices you can use when you use Docker. First of all, who am I? I'm Andres Cidel from Vincorvis, which is a Mexican company, software company. And I'm a full stack developer. I've been using Docker for two years, almost two years now. But I've been doing some dev operations, automating tasks, managing infrastructure. So nowadays, I don't know what am I. So let's talk about a little bit of the content of this talk. We're going to know how containers works. What is behind the scenes when you use Docker containers? And we're going to list the main concerns that you have to keep in mind when you use Docker and how to create and maintain security images because images are the base of security in Docker and how to limit risk and good practices. This is a lot of tips that we're going to share with you. So how Docker works? The first thing that we have to keep in mind is that containers are not virtual machines. Virtual machines use hypervisor to manage the execution of a guest operating system. So containers are quite different.  Containers can run services. You can install packages in those containers. Containers have network interfaces, but they are not virtual machines. They feel like virtual machines, but they are not. Containers are possible because of two feature kernels, which are C groups and namespaces. So what are C groups? What's this feature? This feature limits accounts and isolates the resources of the host. And if you have CPU memory, this network IO, it says, okay, I'm going to give two gigabytes to this container. I'm going to enable these network features for this container. And manage this as a hierarchical group. All the children of a process is going to have the same limits. And what are namespaces? Namespaces is the feature that isolates containers. The processes will have their own system view. When you use containers, for example, do PS in a container, and you're just going to see just the processes that are running in that container. So you can isolate a file system, memory, user, and networking. That's the reason it's like a truth with steroids. Containers are truth with steroids. And then C groups limit how much you can see, and namespaces limit what you can see. Okay, and next, what are kernel capabilities? In a traditional Unix system, we have two kind of processes, which are privileged processes whose effective user ID is zero. Basically are the root processes. And on privileged processes whose effective user ID is not zero. And these processes are attached to full permission checking based on the process. Permissions, et cetera. And Linux kernel capabilities allows us to fine-grind these access control system. For example, a capability, this capability shown, make arbitrary changes of the file. This allows us to change the permissions of files, and we can make these changes in every single file on the system. Okay, if you browse the code of Docker, the source code of Docker, you're going to see a list of capabilities. This is the default list of capabilities that Docker has as default. And if you want to see a complete list of the capabilities that are supported by the kernel, that's the URL, and you can study. So what are the main risks when you use Docker? What are the concerns? First of all, the Docker daemon. It requires root privileges when you use the Docker daemon. So if you control the Docker daemon, you will have access to the root. And if you enable the RESTful API, this is not authenticated by default. So if an attacker discovered your API, remember that if you have root access to... Well, if you control the Docker daemon, you will have root access or root privileges in the host. So how can I secure the RESTful API? Well, you can enable the TLS by using the flag TLS verify when running the daemon. And you can create a CI server and client keys. That's for authentication, but what about authorization? And Docker's out-of-the-box authorization is all or nothing. You can do everything or you cannot do nothing. So Docker provides a generic API, so you can create an authorization plugin by yourself and bypass this problem. And escaping is another concern. This is caused by Halloween privilege operations, not removing all possible capabilities, weak network defaults, and obviously boxing application code. It means that containers sometimes have a lot of capabilities. And if you add other capabilities that you may not need, this could be a problem. Remember that a user in a container with root capabilities could be wrote in the host. So how can you prevent this? Well, I'm going to explain each item of this list. So first of all, drop capabilities. As we saw capabilities, with capabilities, we can perform root operations or operations that requires root privileges. But for example, in this case, in this example, I'm dropping all the capabilities. Basically, running a container like this, you can just run a clock, for example. Basically, you can do nothing. Drop a single capability. You can drop, for example, a drone. And this container won't be able to change permissions. And you can combine flags. For example, drop all capabilities and add the capabilities that you're going to use. And I think you're going to start asking, how can I know which capabilities I'm going to need? So the answer is you have to keep in mind which capabilities you could use, or you can study them. And if you think that you have in your code a process which could use a strange capability and you are not secure, you can run your test. If you have a set of tests, you can run them and see if you need or drop or add a capability. And remember that containers just have to be... Containers have to have no more than they need. Okay. And this is more easy. Enable AppArmor. AppArmor is a new security model which is in charge of secure the operating system and the programs. So AppArmor uses security profiles to create a granular configuration over capabilities for your containers. And then if you are using Ubuntu right now, you probably... It's installing Ubuntu and it's running. You can check it with this command, AA status, and this is... This command is going to list the profiles that are loaded. Well, once you create your profiles, you can load them with this simple command. And if you want a container with this profile, you just have to indicate what's the name of your profile and that's all. Sometimes it's quite simple. And there is this tool which... His name is Bain. It's used for create profiles in an easy way. And define a user. Always, or most of the cases, is better if you create a user inside your Dockerfiles with the user add command and add a user directive, not your containers with root access. And multiple containers. This is a big topic. This could be another one-hour talk, but I'm just going to list the benefits of this approach. Basically, the benefits are limiting containers, limiting attack scenarios, helping prevent compromise your containers, simplifying development, allowing for easy upgrade parts. And it's very easy to run, just with the flag grid only. You can freeze the file system. If you run a container with this flag, and, for example, an attacker breaks out the container, the attacker won't be able to write any file or edit any file. Nothing. So it will be better. And you can combine it with using volumes. So you can freeze the file system of your container, but you can add a volume and write on that volume, so you can combine these operations. And another big concern is image provenance. So when you use systems that communicate among networks, trust is the central concern.  So how can you verify that you're getting the exact image that the developer has created? Or how can you know that the image has not been tempered with? Docker has solved this problem with Docker Countertrust, which basically signed the images with certificates and using digital signatures. And it's very easy to activate. Just export Docker Countertrust. That's all the first operation that you do as a publisher. For example, build, run, or build, run, or pull images. And it's going to work with this feature.  So you don't need to worry about nothing. You don't have to learn a special combination of the commands, etc. And why Docker uses Docker Countertrust and not a GPG? Because Docker Countertrust creates a digital signature with timestamps. So you can enable it, you can disable other images. For example, this image is no longer available, so you have to download this. So with this approach, you will have the up-to-date images on your containers. And of course, you have to create secure images, which is the next topic. How can you create and maintain secure images? First of all, verify the software. This is very important. And you have to verify the authenticity of the software that you are downloading. And when you're using package management, this takes care of you, so you don't have to worry too much. But if you are downloaded raw files or binaries, you should use, for example, HTTP ease instead of HTTP. And you have to check for signed files and valid checksums with a GPG, for example, when it comes to third-party repositories. And obviously, you could use this in your batch scripts or your background files, not just Docker. Creating better Docker files. This is important because sometimes if you want to have consistencies in your images, it's better to pull the specific tag. So it's better, for example, from Alpine 3.4 instead of from Alpine. And never run as route. Well, this is like the... This is important. This is super important. Always add the user directive. So if you use the user directive, maybe you need the user add comment. And drop privileges as possible. And if you have to use sudo, don't use sudo. It's better to go through. So you can use minimal base images. Ubuntu and CentOS, for example, have 60 megabytes. And if you use Alpine, it's a Linux minimal base image. It's 5 megabytes. And you could reduce attack surfaces complexity and size of the images. This is an example of using Alpine. And with these lines, you can install the Python runtime. Very easy. APK is the package manager of Alpine. So other best practices will arrive whenever possible. Especially when it comes about security features. The Docker demand and client, the Docker engine. About using Docker with privileged flag. This flag is going to remove almost all the limits that container have. So provide non-security. Avoid providing access to the Docker user or the Docker group. As I mentioned, if you have control of the Docker demand, you could have root access in the host. Avoid providing access to the Docker unique socket or REST API to potentially introduce coders or containers. It's especially when you use Jenkins, for example, your Jenkins manage the Docker demand in a certain way. You have to keep in mind this tip. Consider using Docker bench security. This, as the repo says, have dozens of common best practices around Docker containers in production. This is a script and it's elevated privilege for running it. Remove said UID and CGID binaries. I'm sure that you are not going to need them in most of the cases. So it's better not having them. When exporting ports or exposing containers to the network, Docker exposes to all interfaces. So you have to be sure that you are exposing the container, the network to the right interface. And follow best practices when writing Docker files. On internet, you're going to find a bunch of information about this topic and limit the container intercommunication by default. You can communicate with other containers. Even if you are not using the flag link, you can send raw packages. And limit the memory. This could help you to prevent from those attacks. This is the guide that I based this presentation on. Docker is working a lot to provide a lot of documentation about security. So thank you for listening and questions. Hello. I had a few surprises using Docker with IP tables because it injects certain rules for networking. Do you have any tips on how to deal with that elegantly so I don't write some rules and then notice that Docker is actually bypassing them? Is your container, is the purpose of your container managed the network or what you're going to do? So I had a container, basically I was running Kibana.   I wanted the Kibana port to be only accessible from local host and then I noticed that basically my P tables rule saying only from local host except were being bypassed because Docker inserted its networking rules and they were actually circuiting my rules. So it seems to be a common problem. Do you know of an elegant solution? I don't know. It depends of your stack but we can discuss it if you want after the talk. Any more Python specific security issues with Docker? For Python, I've been using Docker with Python for almost one year and I think these advices applies for almost all languages, especially for Python. It could be, I don't try to create in-mode table containers. So if your code has a vulnerability you can drop it with read-only file systems. So that's all. Any other questions? Okay, if not, let's say thank you once more to Andreas. Thank you very much.


Good afternoon, everyone, and welcome. This is Melissa Arma with the Stock Swoosh, and I'm here tonight to discuss an upcoming webinar on a simple 26-point strategy to make money daily. And actually, this is a strategy that I use to trade in the market. If you'd like more information, you can email me at Melissa at thestockswoosh.com. You can also go to my YouTube site and sign up and subscribe to me at the Stock Swoosh because then you'll get all the videos, plays of the days, webinar replays, everything there. I'll email to you immediately if you go there and subscribe. So we're going to talk about the stock market. Why? Because I love to trade the stock market, and this is a strategy that you can use to trade and make money daily. The stock market is accessible to everyone from any walk of life to trade it and to make money. Why doesn't everyone trade then successfully? Well, one reason is they do not have a system that works. You need a system that works and one that works consistently over time and in any type of market. In fact, it needs to work independently of the market. The Golden Gap 26-point rating system works and it works independently of the market. The profitability requires detail. So you can't just go into the market willy-nilly. I was talking to a gentleman today about this idea of being consistent. That's what matters. Now you don't have to have this huge mass of days to cover umpteen days of losses. No, that's not the key. It's having small losses a few times a month, if that, okay, and then having consistent winning days. Then all of a sudden you chunk it out and all of a sudden there you are, you're like, oh gosh, you know, I'm up a lot this month or whatever the case may be. Because if you know that you can go in and hit it, Monday, Tuesday, Wednesday, Thursday, Friday, to hone it down to pinpoint it, that you know that you can do that, like a fine, fine, fine level of detail, then you can consistently make money in the market. And it's the 26 points that teaches you that, that tells you that. Here is an example. This is QCOM, okay? QCOM was a gap here today, July 23rd. The 26-point rating system tells you that this is a short, okay? So you wouldn't be looking to buy QCOM, you're looking to short it. Again, you have to have the directional bias correct in your trade if you're going to make money. How do I have the ability to take trades and go into the market and risk my own money every day because I have conviction? And the 26-point rating system gives you conviction. A lot of people are in fear about trading, but you can't be in fear if you want to make money because you have to take risk if you want to make money in a trade. In the market you must take risk. You do not make money if you do not take risk, okay? There's really nothing like trading with conviction. There's just no comparison. The golden gap 26-point rating system gives you conviction in your stock pick, your bias, and your analysis to trade the correct entry on the day. And it also assists you with target and profit taking. So you don't exit the trade too soon, okay? Because you want to try to hold it as for the most move that you can. I call it 100% conviction because it's like night and day. Like I don't take a trade up and on conviction. And if I do, then I take it. And this is where you have to get to the point. So you can start to make more money in your trades and have less losses and be more consistently profitable. It's all about having a plan of action. You need a plan of action. And this plan of action will help you to be successful trading. And you need a proven strategy and a system that works in order to make money trading. The 26-point golden gap rating system is a plan of action that can help you achieve profitability and trading success. And it's really about the points. It's about the points. And it's very simple. You just go through the checklist. One, two, three, four, five, six, seven, eight, nine, ten. You just go through the 26 points every morning to decide which stock to trade. And then you know which direction to trade it. And you focus on that. And you take it. And this is where you have the success. So I teach a class. The class is called the Golden Gap Course. It is a two-day course Saturday and Sunday from 9 a.m. to 5 p.m. eastern time. Cost of the class is $34.99. If you're interested in more information, you can email me at Melissa at thestockswitch.com. Remember, you've got to educate yourself correctly if you want to be successful. It's like you're giving a present to yourself because you're investing in yourself to be successful as a trader to do this, to learn how to take the risk and what to take the risk in. To learn where the entry is, you learn all of this in my class. I do have a live trading room. The live trading room is only open to join if you are a student of the Golden Gap class. And I run the room from 8.30, 11 a.m. eastern time.  So if you're interested, feel free to come to the webinar. It's July 27th at 4.30 eastern time. Email me at info at thestockswitch.com if you would like to sign up. It is free. And I will see you at the live webinar. Have a great night, everyone.


Hi you guys, Lindsay here. Welcome back to my channel Inside the Hymn. I am so excited! McCall's fall patterns were finally released maybe yesterday. I was on my way back from Boston kind of dealing with a bit of drama here with the hurricane evacuations, but McCall's is typically my favorite pattern company when it comes to design. Their designer Jackie Polakoff is just, in my opinion, right on the mark always when it comes to trends. I just really, really love their patterns. So I'm very, very excited to see what they have for us today. So we are going to jump right in to the McCall's fall first impression review. Okay, so first up, let's do it this way, is a Laura Ashley, Mrs. and Petite dress pattern. Okay, so we have a long-sleeved dress with a little neck tie, and it looks like some layers going on there. Here is a shorter version with a variation on the collar. Here are some line drawings, cute. It's like a shirt dress with like a peasanty kind of skirt.  Here's our line art. So we have this kind of very dramatic high collar, you know, giving a little bit of a nod to the Victorian thing again. We saw that in the, oh gosh, there's been so many patterns coming out lately. They're all mixing together. Was that butteric, or was it new look? Maybe it was new look that had that Victorian brocade dress. So Victorian sleeve cuffs as well. But then you've got this kind of like gathered skirt giving a little bit of a peasant vibe. So it's kind of a lot of stuff mixed in here.  But then you have this really girly skirt. I do think that the gathered and layered skirt is to me more fall than any of the other seasons I guess. Okay, here's another one. This is a creative pattern. I like the creative patterns. You know, it's where you can kind of take bits and pieces from each dress and mix them together however you want. All the pattern pieces when you actually go to sew it are separate from each other. So it's very easy to kind of just pick and choose what you want your end design to look like and then just grab the specific element that you need to make that happen. So this has a ruffle strap detail. It's also got these flutter sleeves with this wide collar, center front seam, some darts there. Then this one's nice and you've got this sheer kind of crew neck illusion, you know, neckline with the, you know, main part of the bodice. There it is with no other embellishments but an embellishment to the skirt. Interesting. This one is just a little, a lot frilly, very, very frilly to me. Lots of ruffles. So you can see here all the pattern pieces, one, two, four, and seven. I'm guessing one and seven are the bodice and skirt and then two and four must be maybe this collar and the sleeves and then three is the illusion and then eight is the skirt bottom. So you can see how you can add them all together to create a different look depending on which pieces you use. I do really like this one. I think that that is really, really great. I wish that they had one more pattern piece that made this an a-line skirt or pleated skirt or something, not hard to do yourself. You can pretty much swap any skirt so long as there's a waist seam. You can just mix and match your skirts but it would be nice to have it all in one. But this neckline is super flattering, super elegant, would be great for the holidays or, you know, any wedding or event that you had to go to. So yeah, cute. Okay. Next, okay, look how pretty this crush velvet looks. A plus for photographing that in a way that, you know, looks presentable. I think even maybe the color of the velvet helps a lot. But either way, back to the pattern. So we have a ton of ruching. Ruching all the way from the bust line all the way down past your hip. And it looks like if you guys saw my sweater that I made that had that like shawl type thing with the gather detail in a bow around this area, it looks like that's how this is done too. This ribbon runs all the way up through here and back down again and you pull it up tight and it creates all this ruching. Very cute, very well executed in this fabric too, I think. So here it is as a gown with no sleeves and it looks like they didn't tie it off with a bow here either. So they maybe just have elastic running through. Here's the version she's wearing. That's really nice. I mean it is figure flattering but you guys this or figure hugging but this stuff hides so many quote unquote imperfections or you know body types. I don't want to say it in a negative term because like whatever figure you have is beautiful but this will camouflage a lot of it that you may feel uncomfortable about. But it's all beautiful no matter what it is. So here she is again. I mean look how great she looks. That is like so stunning for a party. Oh even a little bathroom shot, that's interesting. I guess just to show how the back is ruched too. Yeah very very elegant. I'm assuming this is just for knits. Pullover dresses have side gathers with either elastic or ribbon, sleeve variations, shaped hemline and a side slit. And then yeah two-way stretch knits velvet jersey interlocks rayon spandex. I also think you could pull this off in a very lightweight ponte or scuba but I gotta say I really this is the first time maybe ever I've seen a pattern in stretch velvet that I would actually want to wear. So excellent excellent work with that. Very cute. Okay here is oh shoot. Here is another long sleeve dress. I was realizing as I was packing for Boston that I really do have a shortage of fall dresses. I found myself wanting to wear a dress but all of mine were a little bit too springy mostly due to fabric choice so I really want to try and focus on making some dresses that are appropriate for fall both in the style of them but also in fabric choice. So here's one it's long sleeves sort of just your basic bodice and a-line skirt and then I think we're just going to get a bunch of sleeve variations but this one is like maybe with some kind of satin and then a sheer sleeve that's executed also very very well. Hemline pretty short which is I think nice to balance out how covered up you are on the bodice. It's nice to show a little bit of skin on the leg. Okay so here's our basic bodice same sleeves but a pleated skirt. Very nice. This has one of these hem details. I like this circle skirt. You don't really see those in patterns as much. Is this the pleated skirt with those ruffles or is that a paneled skirt? I can't really tell. It's sort of outfitting but we can look past that considering they just make a sample and hope she fits into it. Yeah so I think we just have the two skirt options. Yeah the one I'm assuming this is pleats right? It's either pleats or panels. I'm having a hard time being able to tell um just from the line drawings. Judging by how wide it is on the hem I'm thinking pleats but line dresses fit it through the bust with sleeve and skirt variations and back and visible zipper separate pattern pieces. Oh it does have the um bust the different bust sizes that's good and A and B have pockets. Yeah y'all think this is panels I don't know I can't tell.  So that's that guy. Okay now we've got a little coat or not so little coat it's very long coat. All right so we've got a coat with no collar just kind of like a scoop neckline possibly zips up with some steaming going on. Not sure what I think about that. This one's cute with the hood and the fur although you know kind of seen that one before I might even have a pattern like that. This one's very elegant it reminds me of Meghan Markle but you've got these princess seams that go all the way up to the shoulder instead of just going into the bust they go all the way up and then same thing for the skirt you've got a two-way zipper here a nice elegant waist seam oh fur on the sleeves cute and this is a longer version this is like all the way to the floor. I can see this maybe not out of a coating maybe make it more of a coat again and do it out of like a sweater knit I think would be nice I guess it depends on where you live you know she was hot the day they took this pic these pictures it is not cold enough in New York City to be wearing a coat but that one is really cute I do love a fit and flare coat here's some back views all right very nice here are our line drawings how do you guys that make coats every year do you just make one coat every year do you make multiples how do you choose which one I feel like coats are such a statement that well and they take so much time that you really could only make one a year okay here is a fur coat or this one is made out of fur but it looks to be a notched collar I can't tell if there's any closures here or not here it's kind of like a blazer there's a longer version here she is styled perfectly with leather leggings and knee-high boots keeping everything else simple because this is so bold wow yeah a coat pattern specifically for fur that's very interesting I wonder if they would give you lots of tips on how to sew with fur there are some tips and tricks that are out there and I wonder if they would illuminate those in the pattern okay we've got a little pull-over cape with a stunning collar detail I love a stand-up collar this looks great cute collars very on trend with the gray and pink here's a solid one oh here's an interesting one with a zip up now this is something that I would definitely make and wear for our weather just simply because layering is the name of the game down here whenever it gets to be like fall and winter and depending on what fabric you make this out of it could be all you need for winter you can throw it on over just about anything and then take it off whenever you get inside and warm up or as the temperatures outside go up you could definitely you know just put it on and take it off as the temperatures go up and down throughout the day I want to see a close-up of this sweater or knit or do you think that I don't know that's a really interesting fabric I love that fabric it was definitely purchased that way but there you go so you have some different lengths I think this is a longer one and this is a shorter one and then you've got the zip detail which I love especially with the exposed zipper tape and then you've got this one with the toggles I think this is cute I love these ponchos and I mean how hard can that be to make I would be torn though I love this collar but I love this zipper too I guess I'd have to make two darn all right next up we have some mrs. and men's this is a popular trend among sewing patterns lately to do a unisex pullover we just saw that with the new look patterns so here is our McCall's version it looks to be like a more like a sweatshirt or a hoodie you've also got these kangaroo pockets they did this one in some kind of fur he's in a camo probably sweatshirt fleece basic sweatshirt sweatshirt with some details a hood and a kangaroo pocket here she is in her fur here he is in his camo back views yeah nothing exceptional in terms of like style lines or details they're kind of a basic which is okay here's this okay we have got another kind of version of a pullover top this one does have some other details to it like this drop shoulder I think they did a contrast fur on the sleeve which is interesting but it's also got this little like kind of like oversized mock turtleneck oh what we did the sew on pearls like I did for my jeans in a lightweight um some kind of sweater knit there's a tur a full on turtleneck so they inserted that like alpaca type fur that's interesting who was it indy which indy company did this v insert a couple years ago was it the norwegian one swedish one I can't remember their paprika was that their name somebody did something similar to this a couple years ago here's your full fur pullover yeah fur is going to be really big this season I got some fur on sale from style maker fabrics I'm not sure if she still has it or not it came in and it's awesome Sunny was very confused he did not understand why there was an animal on the floor not moving okay cute here we have okay here we have a woven top kind of like an oversized half placket blouse um collars and everything very oversized though or loose fitting um very slouchy kind of boyfriend feel to it it does have these drop shoulders another very popular trend this season is the drop shoulder lots of patterns coming out with those even more so than raglan or dolman these drop shoulders are really kind of everywhere they did a half tuck on this so I can't tell if this is has this in the front or if it's literally that short we'll look at some line drawings here in a second here's the most basic version this one reminds me of the cali here's a long sleeve version I do appreciate that they featured a plus size model what or what I call a real size model this is nice this is very nice I love that detail yeah cute let's check out view D and see what's really going on with that so C has a curved hem and then D that is D right yeah so D is short in the right it's hard to tell D is short in the front and long in the back so they did tuck it in but not that much I think D might have the same front piece as C yeah yep yep so cool and then all the backs have that um ruffle and yoke detail nice another sort of basic but um still stylish I feel like this is something you would see in like antelope loft um you know it is basic but I think that made well and in the right fabric could be very stylish okay now we've got okay a mock a turtleneck with a one shoulder cut out doleman sleeve pullover top interesting okay so we've got a couple sleeve options here we've seen these sleeves for about a year now or maybe at least since spring mock turtleneck center front seam oh okay center front slit so you will expose your cleavage can't wear a bra and two exposed shoulders in a ruffle detail here it is in its kind of basic form very interesting I could see myself making the this version D like I really could especially in some of those knits like I'm assuming this is her knits um in some of those like sparkly sweater knits something that would make it a little bit more yeah moderate stretch knits only something that would make it a little bit more dressy even in like a black fabric it looks like this one's illustrated with maybe like a rib knit or something I don't know but you would need it to be draped because this is pleated this is not a ruffle sleeve this is actually a pleated sleeve um I don't know if what I think about that I might swap out the pleated especially with this and this I feel like the pleated sleeve is kind of a lot so I might swap it out for just the basic sleeve but don't be afraid of this this isn't that revealing I mean I wouldn't wear it to work or anything but to brunch for sure I mean why not I don't know this one is memorable you know it's one of those ones that I will have in my mind even after I finish looking at all of the patterns and that means something I think okay here is a palmer plush pattern so you know that you are going to get some impeccable fitting with it and lots of tips and tricks for how to fit this properly it is a little bit slouchy a little bit oversized but not too too much um in fact this is a little bit long on her shoulder I don't know if it's meant to be that way I'm guessing not um but it's got this really cool like wrap around detail I think those turn into pockets maybe let's see if we can learn more as we look at the pictures if this is a shirting I think that that is brilliant I think that's really clever it's like fabric origami or something here is some contrast fabrics that's kind of cool three different fabrics here she is out on the street and a cute outfit oh and then you got another little mid-back detail here okay so no it does not tell us if they are pockets or what exactly is going on with them but we've just got I think the only variation on all of it style line wise is the sleeve so you've either got this little bell this little sleeve with a slit you've got a sleeve tab sleeve tab or and then this maybe this is the sleeve tab unrolled I don't know you've got this long sleeve version too um let's look into this and see if they talk to us about pockets um semi-fitted button-down shirts have sleeve variations and shaped hemline wrong side of fabric will show no they don't say whether those are pockets or not so let's assume they aren't cotton blends linen polished cotton chambray so yeah they are recommending shirting type fabrics but you could even go into like a rayon world here make this a little bit more drapey um not shally but maybe a rayon cotton blend would be really nice and you just get a little bit more drape and kind of like loosey goosey fabric but if you are using a shirting you're going to get a really crisp look here and this I think is just like taking your standard button-down and just elevating it and making it super stylish and super cool and interesting where people know that like well maybe they don't know that you didn't buy it in a store but they're going to stop you and say what an interesting shirt where did you get that you know what I mean like they're going to see and I think it would be really cool to see how this would all go down in a stripe or in a plaid I mean this version here they kind of went into that but I want to know if you used this stripe all over you what would happen to this little wraparound thing you know what I mean like how cool would that look would it be on the bias would it be just still vertical stripes like I'd just be interested to see how that would work out you know very interesting very thoughtful right next up we've got another yet another top this one is okay your same button down it does have a forward shoulder or front shoulder yoke I can't tell that's a yoke or a forward shoulder seam but you've got these huge puffy sleeves with the exaggerated long cuff shaped or curved hemline you've got a bow detail which you guys know I love a bow most of the time I don't know it would just depend on fabric choice this isn't really selling me on this one though this is interesting I love this little detail with like this almost like a cowl sleeve can you call it that a cowl sleeve I think that's adorable and floral as well excellent illustration there we've got a huge puffy sleeve this is very kind of 80s to me here she is back yoke with some gathers right so another you know every single um option has the same bodice and just different sleeves which I think is totally fine I think you would learn a little bit at least I think I would about how drape and construction works especially with that cowl that sleeve pattern has to look very interesting when it's laid flat here's one that y'all know I'm going to love because it has a lace up detail similar to what I did with that sweater that Jay grew inspiration sweater that I showed you guys in my makes very cute this has a drop shoulder again no bust darts or any kind of shaping there you're getting your volume just through the the drop shoulder here it is with a collar and a sleeve ruffle and a kind of poofy sleeve and a long exaggerated here she is with pleated him this has some like pickups it's also kind of short I'm not sure about proportion here it's very voluminous here and then yeah I don't know I do like all the different details maybe it's fabric choice you know maybe this were like a little bit longer also that would help I like this one best and I kind of want to make it out of like a sweatshirt place let's see what kind of recommendations we have fabric wise here loose fitting top with drop shoulder has neck length hem and sleeve variations and back hook and eye closure side detail with two part romance and ribbon sleeve with pleat detail and all lovens but you know it's just a suggestion yeah I don't know I'm kind of on the fence about how this would look on me she obviously has a very slim figure so I think that that you know does well for her to give her kind of more broad shoulders and then cinch in at the waist I just don't know how that would look on an average person but I do love the details this might be one of those things that you could make some modifications to simple ones like lengthening it maybe adding a skirt you know cutting it off at the waistline and adding a skirt maybe lengthening the back and giving yourself like a back long hem I don't know you'd have to like play around with it a little bit and think about your own body shape and what would look best on you okay this is a jumper which is very exciting these have been around for a couple of years now gosh I made one two three years ago I was in the old apartment so yeah they've been around in the indie world for a while so our options are this kind of like peplum right that's your waistline right and then like a little skirt of more of a flared skirt which you know what you really don't see that very often not even ready to wear and someone who is pear shaped like me that actually might look much better than a straight skirt like so this one is very basic but that's okay because you could get like a really cute patterned like you know if you guys saw my new look ready to wear inspiration video similar to how that brocade you know the fabric was such the integral part of that dress here's your more kind of traditional one very cute let's see that skirt yeah that is interesting fun okay cute little flirty skirt here I mean really cute fun flirty skirt got kind of like a mermaid shape to it where the ruffle extends up into the this little like like single princess scene kind of there it is with a lace up love and like a little flounce here it is with a two-layer flounce three-layer flounce how high will they go are you gonna get four layers no just up to three and it looks like we've got single back darts here kind of long though which is nice I like a longer back dart all right so we've got our you know flounce up into the princess scene with a single layer you've got a single layer flounce him with lace up and then a two-layer flounce with no detail in the princess scene and then a three or a two-layer flounce with the princess scene flounce added on top for three layers down there I don't know where you're going in this but it's a party I want to be at probably lots of dancing lots of shimmying it just looks like a lot of fun I do love how they did it in this kind of like a suiting but I imagine that the kinds of fabrics you can use are pretty varying wool crepes suiting fabrics crepes wool blends and then lining fabrics I don't know I think you can even go further than that very lightweight versions of corduroy of leather of especially this one in leather I think would just be like a knockout very very lightweight though you need to be able to get this straight you do not want it to be like sticking straight out like that um yeah you could do a lot of fun things with this one I think cute very cute all right we are still rocking and rolling I think we've got three more by all accounts but let's see this looks like a pleated skirt okay a pleated skirt with an elasticized waist brilliant brilliant execution here showing it with this like gold lame that's one of those fabrics you probably walked by a thousand times and said what would I ever make out of that well this stunning expensive looking skirt is what you would make out of that this would sell for hundreds of dollars at j crew anthropology any of those stores paired with this like ballet top I mean super cute here's a shorter version a mid mid-length version and then a maxi version that is a lot of pleating though you become good friends with your iron with that one I know they say learn to sew for fun oh level two I see yeah I would say that is a level two for sure for sure lots and lots of pleating you become a pro at pleating with that practice makes perfect okay now we've got gosh our only pair of pants our only thing with a crotch so far that's very interesting okay um so this looks to be like a velvet uh it looks to sit kind of low on the waist um a simple band and a bell pant leg then we have her in a skirt very attractive with this pencil shaping very cute so here's a I guess the knee length version with a little side slit these must all be pull-on pants which makes me think they're all knit you know you would use like you know it would be like a yoga pant kind of but dressier oh again pretty basic a learn to sew for fun pattern nothing really to it but if you've never made pants or leggings before you know maybe you would want to start with this then starting with something super complicated but definitely these are all pull-on they don't have any zippers or flies or anything like that super super basic excellent okay oh all right so we've got a legitimate bag pattern so you can see here it's got something interesting going on I can't really tell I'm not as well versed in bags as I am in clothes but this is interesting very cute clutch super cute I would totally buy that from a store um here they are with this little interesting closure thing don't know what to call it a wristlet a tote bag the clutch is awesome that version is really cute too wow interesting I don't even I wonder how many like how much help you get um in terms of sewing with leather or you know whatever these other fabrics are like what is this it's like a woven something it's like a basket weave or something um yeah nothing special all bags are lined with inside pocket synthetic leather synthetic suede denim canvas cotton blends for the lining yeah that's really all they say I might do a pattern review on this just so we all can learn a little bit more about big four bag patterns have you ever made one like this before where it's like you know not kitschy and like made from quilting cottons but actually designed for leathers and stuff let me know okay so now we've oh david tutera made this cute little furry vest okay little girls clothes kids toys and costumes oh my gosh let's just end looking at the cute dog clothes um my goodness um all right so that's going to do it for the mccalls fall pattern first impression review I'm very interested to see what you guys think about some of these patterns honestly there oh my gosh honestly there are very few of them that I would not add to my pattern collection for one reason or another I pretty much liked them all um it would just be a matter of designing them first finding some fabrics that I like applying that fabric to the appropriate pattern um and then making decisions from there because I can't I'm not going to buy all of these but some of them definitely piqued my interest definitely would fit into my pattern collection um and not be too similar to something I already have so that is really exciting and with that I am going to let you guys go leave in the comments what you guys think about this um let's chat what do we like what do we not like what are we thinking about the fall trends um so on and so forth but until next time that's going to do it for me I will see you all very soon bye


Hi everybody, I'm a dumb. I forgot to do the the non numbered card randomizer for The 2022 tops inception baseball break pick your team number three So one person will get all the all the base cards for those teams in that tab down there just those teams One person will get those non numbered card base cards all is one lot new dice new list name on top after three and a one four times one two three and a one four times and There you go. Dusty Dusty had the odds Dusty will get those non numbered cards for that for just those group of teams Thanks for watching everybody. I'll see you next time for the next one. Bye


Okay, so you're probably wondering, well, so just what is an actual open education roadmap look like, and here's one on the wall behind me that I developed for the work that we're doing at the open education consortia. So that you can see what a finished roadmap might look like, and let me try to show you a few pieces perhaps up close and a little bit more detail. So starting here on the left, we start with what it is that we have in place already. And each of these orange rectangles represents different initiatives that we have underway. And then to the left of them, as you can see, are descriptions of the assets, the people in community, the operations and sustainability aspects of them, and the values, the value proposition and benefits associated with each of them. And so all of those have been documented down this side as a starting point for what it is that we have underway with our open education initiative. And then going forward over time, over a two-year period of time, I've kind of mapped out a plan for each of those open education initiatives that take them forward in time. So how will the open education consortia itself evolve over time? And what are the components that are going to evolve? Is it the people in the community? Is it the operations and sustainability? Are we changing or enhancing value propositions in some way? Trying to document a bit of that. And then the black lines represent how the plan connects to the starting points of initiatives at the beginning. Or in some cases, like this particular example right here with the little kind of spikes on top. This is like a new initiative that isn't yet in place. So it's not at the start, but it's something that I'm planning or imagining doing about a year out. And then across the bottom, I put in place for each of the four principal categories what it is that I think we have for others that others might benefit from receiving from us. And what it is that we need from others, how we might actually benefit from sharing from others who are doing open education initiatives themselves. So this is what an open education roadmap looks like when it's finished. It's kind of, it's super useful actually as a way for depicting what you're doing and for talking to others about what it is that you could do together. And so I hope you'll engage in this activity, have fun with it, make them roadmaps your own and please make sure you do a roadmap and we really want to document all the roadmaps that get produced at the summit.


The Independent National Electro-Commission has taken delivery of innovation technology tools that will enhance results management process, accuracy and the commission's operational effectiveness. The tools, according to Development Alternative Incorporated DIA, the firm that developed it, is aimed at responding to specific challenges encountered in the implementation of electro activities. The Chairman of the Commission, Prof. Mahmoud Yacoubu, while speaking at the handover of the innovation technology tools, Athos Zenabuja says the tools will foster efficiency, speed, due diligence and trust in future electoral process. AI and its consultants work closely with the technical team and directing staff of the Commission. The tools seek to respond to specific challenges encountered in the implementation of electoral activities, thereby bringing technology to enhance the operational effectiveness of electoral activities. The tools, therefore, offer innovative solutions that will foster efficiency, speed, due diligence and trust in the electoral process. The tools are not specifically designed for a particular electoral site, hence the utility to future elections and electoral activities. In fact, the support to PINIC under the opening of support to democratic governance in Nigeria, phase two, covers the period from 2022 to 2027, traversing two electoral sites, 2023 and 2027. The commission will closely examine these tools with a view to adopting or treating them where necessary. The original plan was to get these suite of applications ready for 2023 federal elections. Unfortunately, because of initial teaching problems, only two were partially deployed for the election, albeit on the final basis. However, we also knew at the time that we were building, as you said, honorable chairman, we were building applications not for a season of elections but for many seasons. The six applications and software that we want to present today, in fact, on the goal there are eight of them. Two, which are not ready yet, were still trying to finalize them. One of them linked the Omis database and the ENDEC press.


Cities are the heart of modern civilization. They house the seats of governments for most countries, administrative centers for businesses, transport hubs, and in the modern era, the majority of the human population. If you're making a fictional setting, whether it's fantasy, sci-fi, or something else, you're probably going to have to include multiple cities in there somewhere. But you can't just pick a spot on a map and put a big settlement there. There has to be some reason for it. A city doesn't pop into existence on accident, and it isn't just a collection of buildings either. So if you want to learn more about how to make a well-put-together fictional city, keep watching. If you don't, then why not watch one of my many other videos? Please. I want you to look at the maps of all these major cities and see if you notice anything that they have in common. Do you have it? They're all along a river or the coastline. And the reason for that is simple. Trade. The main purpose of cities is economic. They provide a central place for commerce. Farmers and herders trade food for manufactured goods like clothes and tools. The dense population and infrastructure of a city allows for people to specialize in different jobs, which are needed for a complex society to exist. Imagine if you had to make your own food and clothes. Modern life wouldn't be possible. In modern society, the majority of businesses exist in cities because they want to be close to other businesses so that they can work with one another. And in ancient times, the best method of transportation by far was sailing. It was faster and safer than overland travel, and even a medium-sized ship could carry way more cargo than a dozen mules and horses. So cities usually had to be on the water in order to facilitate trade. And even in the modern day, shipping by water is often cheaper than other methods. There are exceptions to this rule, of course, but major cities that aren't on the water usually popped up as a result of being centrally located along land trade routes. Denver and Mecca are both examples of this. When people are forced to trudge along on land, they need places to stop and rest. And when multiple groups of them stop at the same place, they trade with one another. Soon enough, some more infrastructure gets built up and the area becomes a city in its own right. Now, you might be building a setting with more advanced technology. Maybe it involves people colonizing planets and other solar systems. If that's the case, then water will probably be less crucial to the infrastructure, but you still need to take into account the sorts of infrastructure that people used to travel to and from the city. Let's imagine that someone founds a city on Mars. We'll call it Bruno. The primary method of traveling away from Bruno is on monorails powered by sick beets. They wouldn't want to build a city on top of a mountain. It would make building the monorails more difficult and going uphill would require them to use up more of their limited musical fuel. It would be much easier for them to build on open, flat land. Another thing to take into account when looking at a city's placement is what sorts of natural resources are nearby that it can take advantage of. Tying into water is fish, which can be a great source of food for communities.  Ideally, the city should be near some sort of resource, but not right on top of it. That way they can control it, but not have all their houses and roads get in the way of extracting it. So basically, don't just pick a random spot on the map and decide that a city should be there. I'm looking at you, Kamen. With cities being a hub of wealth and administration, they also tend to become a target of hostile military forces. Many of the most famous battles and sieges in history took place in or near cities. Capturing them can also mean capturing resources, infrastructure, fortifications, and sites of religious or political significance. Because of this, ever since cities have existed, the people in them have built defenses to protect themselves. The most obvious and common type was a wall. Just build up a bunch of bricks and it prevents armies from getting in easily. A small number of people on a wall can defend from a much larger number of people on the ground, since those on the ground would need to somehow climb the wall, break through the wall, or break in through a gate. It wasn't uncommon for there to be multiple sets of walls either. That way if the enemy was able to get through the outer wall, the people could retreat behind the inner walls. And oftentimes there was an ultra fortified position called a citadel that protected the most important parts of the city. Usually this was the homes of the ruling class, and in some cases it was used to defend from both outside attacks and peasant rebellions. Citadels had walls, but also included things like castles and moats to make them even harder to take. So it was almost always able to hold out longer than the rest of the city during sieges. Sometimes in addition to all of this, the city would be laid out in a way that favored the defenders. The streets could have been narrow and winding so that attackers would become disoriented and wouldn't be able to bring their full force to bear. The defenders could let the attackers into open areas and fire at them with archers or something. Urban warfare has always been a nightmare, and you should feel free to use your imagination to make it even worse. However, the importance of static defenses drops significantly as technology becomes more advanced. Once gunpowder was invented, attackers could just use cannons to pound stone walls to dust. Once bombers were invented, they could fly over the walls and drop explosives on the people inside. So in the modern era, defense depends more on having a mobile army that can move to intercept attackers. Fortifications are only really useful on a small scale. A wall or trench might not protect you from artillery, but it can protect you from a group of men with rifles. Once technology reaches a certain point, focusing all of your resources on something that can't be moved is no longer worth the cost. The only exception to this should be something that also has offensive capabilities. Think of the Mack guns from Halo. They're gigantic rail guns that can fire from a planet into space, and so any enemy fleets that come close enough to attack will get blown to bits. A lot of science fiction has similar technology, like giant lasers or nuclear missiles. These are all basically just big weapons that act as both swords and shields, if that metaphor makes any sense. If you have magic in your setting, then this might have the same effect. A wizard who's able to summon earthquakes won't be stopped by a wall. If that's a threat to the people of the city, they would most likely come up with some sort of different countermeasure, like magical wards or even just paying off their enemies to leave them alone, which happened a lot during history. There are more types of defense than just man-made ones, though. Sometimes the city proper was built on top of a hill so that any attackers had to climb upwards before they reached them. If there are any forests or other cover nearby, it was removed to prevent attackers from having any. There's also the matter of the water. Since, like I said, most cities are along a river or a coastline, that's very much a double-edged sword. Obviously, men and horses can't charge at you from across a harbor, so at least part of your perimeter is safe. But that leaves you vulnerable to attacks from ships, and therefore you need your own navy to defend yourself, or at least some sort of ranged weaponry like cannons.  Venice is one of the best real-world examples of this. In its early history, it was connected to land by marshes that were difficult to cross on foot, so any army had to come at it from the sea. But the Venetians prioritized building a navy, and consequently they got really good at sailing and shipbuilding. Almost no one could match them, which meant that almost no armies could even reach Venice to attack it. But even if they could get past or destroy their navy somehow, they would have trouble taking the city. Since it's actually made up of a bunch of small islands, the people got around using canals that would have been far too narrow for big battleships to navigate. So any amphibious invasion would still have to stop near the edge of the city and let their infantry try and navigate that mess. In the era before gunpowder, Venice might have been the most well-protected city in the entire world.  In fiction, this can be made a million times better or worse. If there's a race of sea people that can breathe underwater, then they can probably attack from the water without boats. If a wizard can dam the river downstream, then they might be able to flood the city without fighting at all. The trick to making this sort of thing logical is to just think about what sort of threats the city might face and then think about what sort of countermeasures the people might have for that. Of course, keep in mind that a lot of these are expensive as hell, so if the city doesn't have money, then they could very well not have proper defenses. We all need food to eat. I don't think that's news to anybody. And cities, for the most part, can't make their own food, which means they have to have some sort of relationship with the surrounding area. Towns and villages and farmsteads tend to cluster around cities, since the bigger settlements act as centers for government and commerce. These smaller settlements will produce food or other resources in exchange for goods that they can't produce themselves. This symbiotic relationship requires many towns and villages to support one single city. This also means that food tends to be more expensive in urban areas. The cost of packing, preserving, and transporting it has to be tacked on in order for a profit to be turned, at least in a capitalist society. If something happens to cut the city and the country off from each other, then they're both in trouble. The city will quickly run out of food without an influx of it. Historically, this is why they would usually have stores of food on hand, in case there was a siege or a bad harvest or something else to that effect. The towns and villages will be alright on their own for a while, but eventually they'll run out of things like tools and if an army comes for them, they'll have no one to turn to for help. How much food can be brought in tends to restrict the size of any settlement, but especially cities. If a lot can be brought in, then the city can grow and expand. This often means building more homes and streets outside the current boundaries and even building more defenses, like another wall, for example. The downside is that this is obviously very, very expensive, both to build and to maintain. So a wealthy city can grow while a poor city will often shrink. If you want to make a city that's more independent from the surrounding area, then there has to be an excuse of some sort. Maybe there are large gardens inside the walls that they use to grow food, or maybe they can turn rocks into food, like in the Stormlight Archive.  Keep in mind that all of this is true no matter what the technology level of the setting. New York and San Francisco don't make their own food, just like Lakeside, Colorado isn't making its own cars, guns or computers. And this all ties into the next part. So how big should a city be? In theory, there's no limit to how big a city can grow as long as business and government can keep up with the increased complexity. In practice, though, that increased complexity tends to put a limit on city size based on the available technology. In 2019, Paris has a population of over 2 million people. A thousand years ago, there were barely 20,000 people living there. Because of slow transportation and lack of refrigeration, food couldn't be taken from all over France like today. And since there was a lack of things like sewage systems, indoor plumbing, and modern medical care, disease was rampant. Not that it wasn't rampant all over the place, just that it was worse in places with dense populations. And the more people that are packed together, the worse the problem gets. With proper sanitation, the problem is no longer as big. However, to get proper sanitation, you need to have a functioning local government. There can't just be one noble with some soldiers, there have to be planners and workers that keep things clean. And then there are problems with things like traffic and tax collection. Bureaucrats and rules are needed for cities to run properly. If they don't have those, then they won't be much more than slums. And if that's what you want to create, then go right ahead. Just keep in mind that the population's ceiling is lower in that case. And again, this is something that becomes less pronounced as technology advances, but there still needs to be some level of proper management to keep things running smoothly. Cities are the center of human civilization, so it's going to be almost impossible to build any sort of setting without including them in some way. And if you're one of those people that spends every moment obsessing over worldbuilding like I do, then hopefully this video was helpful for you. And if you're not, then why the hell did you watch this far? At some point in this, you might have been thinking that there was some overlap between this subject and the subject of my last how-to worldbuilding video. And yes, yes there is. That's really the secret to good worldbuilding. Remembering that everything is connected. Economics affects how wars are fought, wars are influenced and are influenced by religion. Religion affects how and what people eat. The list goes on. So if you take nothing else from my channel, take this piece of advice. Everything ties into everything else. Change one thing and you'll change everything else. Also, subscribe. Special thanks to all of my patrons who voted on this topic. If you want to participate in polls to determine future topics, then check out my Patreon page down below. Bye.


Hello, everyone, and welcome. This is Melissa Armo with the stock swash and reviewing the market here today. Some nice calls here today on the options newsletter and in the trading room. But I'm specifically going to go over the market here today because the QQQ's gap down today, which you say, why did we gap down? Well, again, anything that has to do with COVID that's negative news affects the market. But we also had, I don't want to say positive news, but we had less unemployment claims than expected. So you would have thought we would have rallied, but I still think $881,000 is way too big of a number to be having. Week over week, these numbers continue and they're just skyrocketing numbers and they're going on, it seems like endlessly. But the big news out today, which created the market gaping down was the fact that Fauci came out and said the numbers of the cases are too high going into flu season. So the market reacted negatively to that. And no matter how you look at it, the market's still strong. So I called and put in the QQ's here today. It was one day off. And again, we may follow and follow through again tomorrow. We'll see where we are. But this is a nice trade. You could have just traded as an option as a day trade today, got in, got out. Or you could hold it through tomorrow to see where we are. Going into holiday weekend though, it's very tricky. Three day weekend in the market or three day weekend because the market's closed Monday for Labor Day. But today, we gap down after making brand new all-time highs yesterday. We were at 303.50 and today we opened at 298.20. And we've had quite an extension here. I mean, that's not nothing, you know? So about $13 moved down and sliding. I mean, it's only 12.22. I don't think this sell-off here is done for today, to be honest with you. So we could even sell off. And I'm just talking about today. I'm not talking about if we fall through tomorrow morning. We could even sell off down here into 284.283 and change. We're not gonna recover from this today. That's one thing I know. So if you're interested in doing options, the nice thing about options is that you can trade options with a cash account where you don't need a margin account and you just pay the cost. And the cost of some of these trades today that I called in the options newsletter were very inexpensive considering. I mean, because if you would day trade the market here on margin, you know, even here today at 289 and change, that's, you know, you need a good size account to take a full position in this, but as an option trade, you can get the kind of move like this $10 of more and just pay the cost of the put because I called puts in this. But again, the market is very strong. So you do a quick trade in this to the downside a day or two, and then you see where we go from here. Someone asked me in the room today, is this it? Is this the biggest sell-off? You know, I don't necessarily think that this is it. Okay, so be careful, be wise with your trades. Don't forget to take profits. You gotta book the money when you're up. Again, we could see a sustained sell-off here into the clothes, but just make sure you're green, green, green. I'm calling some really nice trades in the options newsletter. You gotta make sure you book the money. Don't be piggy about targets, particularly in an environment like this, and have a great holiday weekend, everyone. If you'd like to sign up for the options newsletter, I'm running some Labor Day sales, email me at melissathestalkschwisch.com. Have a great day.


In this segment we're going to take a look at one of the very important properties of a fluid and that is the viscosity of a fluid. So what viscosity does is it relates the local stresses within the fluid to the amount of strain or shear that is occurring within the fluid element itself. And what we'll begin with, and it's a very common approximation to be making with fluids, we will assume that the fluids that we're looking at are Newtonian and with that that means that the shear stress, we define shear stress with tau is proportional to and what we'll show in this segment, it will be proportional to the strain rate within the fluid and this typically holds for common fluids that we often deal with and examples of those would be water, oil, or air. There are other fluids that we'll talk about in a later segment that are non-Newtonian and for those this type of relationship would not hold. So when we look at this, if you recall back, if you've taken a course in solid mechanics, this relationship looks a little bit like Hooke's law. So it looks a little bit like Hooke's law that you would see in a course in solid mechanics. However, the difference here is that we're looking at the deformation rate and if you remember from one of the earliest segments in this course we talked about the difference between solids and fluids was that when you shear a solid it only deforms through an angle whereas when you deform or apply a shear to a fluid it will continue to deform and so that was the difference between a solid and a fluid and consequently we see it within the equation that we're going to derive here. So what we're going to do, we're going to start with a little element of fluid and so imagine we have a chunk of fluid look something like this and what we are going to do is we are going to assume that there is a shear stress. Well first of all let's define the axis or the size. So this chunk of fluid is delta y in the vertical and it is delta x in the horizontal that gives us the size of the chunk of fluid and then what we're going to assume is that up here we're applying a shear stress and that shear stress is going to be shown to be proportional to the deformation rate of the fluid itself and what we'll do we'll derive an equation for that so let's assume that we apply this shear stress. What will happen is the fluid element itself is going to deform and it will look something like that and this would be at a later point in time and assume that the velocity at which we're deforming at, let's say it's u and I'm going to denote that with a delta u and in a given amount of time the fluid element itself is going to deform through a certain angle and we'll call that angle delta theta and over here we will have a delta theta as well so delta thetas are the same and we know if the fluid element is moving at a speed of delta u and let's assume that this takes place over a period of time delta t we can then say that this distance of this deformation is going to be delta u that's the velocity that it's displacing multiplied by delta t or that time and down at the bottom what we're going to assume is that the lower chunk of the fluid element is fixed so it is attached to a wall and we'll call that the no slip condition we'll look at that in a later segment but for right now let's just say that it is attached to the wall and it's not moving so we can use geometry to write out an expression here so what we have we'll use trigonomic tree we have tan delta theta is equal to opposite over adjacent so that's delta u delta t divided by delta y so we come up with an expression or an equation and what we're going to do we're going to impose the small angle approximation and and so in doing this small angle approximation we're going to assume that all of the deltas go to differentials and so it will be a differential size the very very very small displacement and angle or in velocity so let's take a look at that if we make the small angle approximation the previous equation then becomes this and I've done a little bit of rearranging I've moved the delta t to the left hand side of the equation du dy so if you look back with the small angle approximation we had something like this delta u delta t over delta y and all I've done is I've taken this and I've moved it down there and I've converted the little differential elements into the the d for differential equation so with that if if we look back to what we were saying in the earlier slide that shear stress is proportional to delta theta by delta time what we have here is that the shear stress if you recall that we can say it was proportional to d theta by dt well we see from the equation from this little chunk of fluid what we have is shear stress is then equal to du by dy which is coming from this equation up here I'm bringing it in but there needs to be some sort of constant of proportionality and and that constant of proportionality that we use in fluid mechanics is called viscosity and so we put the viscosity in there that gives us the constant of proportionality for this relationship and what this does is it gives us the force actually it's it's stress but assuming it's over a unit area so the force due to shearing from velocity so if you shear a fluid this would be the force that resists that shearing motion and mu in here is a constant of proportionality and that is the viscosity and it actually turns out that this is what we call the absolute viscosity we'll look at another form of viscosity called the kinematic and it's basically this divided by the density but we'll look at that later so let's take a look at this now so we have this equation we have oops sorry we have tau tau is equal to mu du by dy let's take a look at the units in this equation now tau tau is a shear stress so the units of shear stress is going to be newtons per meter squared and on the right hand side of the equation we have the units of mu for right now i'm going to leave it unknown and then we have it multiplied by a velocity divided by a distance so velocity we know as meters per second and distance we know as meters so consequently what we can do is we can rearrange this and try to isolate and determine what the units of the absolute viscosity are so if we expand this the meters cancel out we have newtons seconds per meters squared newtons if you recall f equals ma a force is equal to mass times acceleration we can expand newtons as being kilograms times meters per second squared and then that's multiplied by seconds per meters squared we have some cancellations that are going to occur there that goes that goes so what we end up with for the viscosity is kilograms and it's divided by second meter per meter second and so essentially what we have are units of mass divided by length times time so those would be the units of viscosity and and you'll see different units in different books but really it could either be that or it could be that for the absolute viscosity now one last thing that i should say and i did mention this at the beginning this is assuming that we're dealing with a newtonian fluid and the characteristic of a newtonian fluid is that tau is a linear relation of du by dy now there are some fluids that are non-newtonian and for those fluids it is not a linear relationship so you would have a non-linear relationship here those are fairly complex fluids to analyze and we will not be analyzing them in this course but i will give you some examples of non-newtonian fluids in the next segment so what we've looked at here we've covered the viscosity of a fluid it's a very important parameter or property that we will be using in all of our analysis