The project came about from one of my students, Pette, he's a mad keen surfer, it was from his keen interest in surfing and research that I suggested that he come on and do a summer research scholarship. I also convinced a couple other students to come on board and we were really interested in the effect of different dry land training modalities have on your surf paddling performance. We see a lot of high ankle sprains as a result of landing aerials and also ACLs on the rise, so it would be good to try to provide some information as to how we could prevent those and keep our surfers on the water and performing at the highest level. We had them in the pool, the primary outcome measures were the 40 meter time trial and they were required to do that three times so it was like a repeat sprint if you like. We also had some tethered paddling so we essentially strapped them to their board, they were then attached to a wire, there was a strain gauge between the surfer and the dive block and from that we could see how much force they were producing. We're now just at the point where we're analysing this data, just eyeballing it, you can see that there is some significant change. Our aim is to then use this information to help guide the exercise prescription and programming of those working with surf athletes. We did measure a whole heap of different variables so we want to try and determine which of those might explain the performance with paddling. When we can understand that, that I think will then further inform practice. These sorts of studies, they are very fun, I do quite enjoy conducting this research but I think implications are quite practical. It's information that can be taken and used and applied straight away so I think that it is very important to have those links between researchers at the university and the practitioners or the coaches within sporting organisations.


Hi, this is Ashley with Oxford Toyota. I wanted to send you over a quick video greeting. That way you can see who you've been working with Thank you so much for taking the time to speak with me last night through email about your interest and trading in your 06 fusion for a new 2015 Camry I went ahead and I put some information in your file So when you're ready to stop into the dealership, please let me know that way I can go ahead and schedule an appointment feel free to give me a call my number is five zero two two and four seven 1166 or you can email them back. Thanks. Bye


Hey guys welcome back to my YouTube channel this is Daniel Rosal here bringing you today's video from the United States of America the land of oversized portions and everything possible that can be ordered from Amazon Prime to your home the next day what a fantastic country and one of the exciting things that you can order from Amazon Prime which I have been wanting to try for years and which finally arrived yesterday is none other than this Kosher MRE for those who haven't heard about MREs and MRE is a meal that's ready to eat it's basically a shelf stable meal that can literally just sit in your pantry for generally years these things are really popular among preppers and for those who haven't picked up the vibe yet from this YouTube channel I definitely consider myself to be something of a prepper but this one is particularly exciting because it's actually a kosher MRE and as a kosher keeping traveler traveling in the US I won't eat meat unless it's kosher so this is actually a kosher certified MRE it's produced by a company called KJ poultry and the one I've gone for is the ready meals bone-in chicken I checked out the listed shelf life on this and this guy has an expiry date of almost 2027 I'm recording this video in June of 2023 so this thing will literally sit on your shelf for four years basically what this is you know it's a bone-in chicken it says here served with carrot zimmas I have no idea what that is potato kugel I do know and farful which I think is like some wheat thing and looking at the front because people keeping kosher are usually concerned with stuff like rabbinic certifications so it says it's got a glatt kosher sign on it it's got a bechule sign on it and it's got another couple of kosher certifications but those are more than enough for me to to know this is kosher so this guy is going to be three minutes in the microwave you can also cook it in boiling water on a hot plate or on a stovetop the list of ingredients ingredients does it sounds like something kind of a little bit out of a chemical factory there's chicken water carrots egg barley sugar food starch and a few other things this thing cost me about 13 dollars on amazon.com so these things aren't actually that cheap but you can also buy them in multi packs and it's a little bit cheaper I actually remember these way way back in the day when I was still living in Ireland there was this program from the Chabad Jewish organization that's probably still going on called the Roving Rabbis and it was these two rabbinical students who would travel around the country to meet Jews in far off places and I'm pretty sure I remember these guys rocking up with one of these kosher MREs so anyway that's enough of an intro I'm very excited to try it I'm gonna put this guy in the microwave and see how it turns out okay so after three short minutes in the microwave we've gone from having something that arrived in amazon prime packaging this morning to kosher meat in the middle of a place where it's the best of my knowledge there isn't any kosher meat so this is it I've just done my plating work and as you can see there is a bit of chicken here and there's some far full I'm going to just use some of my beloved Melinda's hot sauce which is also kosher certified in order to bring up the taste level a little bit I'll put some on the side and try it without at first and I'm very intrigued to see how it goes so let's try firstly the meat and it's you can see here on the inside it looks pretty tender and well cooked I'm not sure how they preserve these things in a shelf stable way but perhaps this is one of those things those questions in life that you don't need or really want the answer to so let's give the chicken a shot um honestly it's not bad I mean this isn't the greatest chicken I've ever had I want to say that firstly but it does it doesn't taste that strange it's kind of what I was expecting that I would have this kind of weird texture from whatever kind of conservation process it just tastes like normal chicken and let's try a bit of the far full now I'm mixed in with it mmm that's not bad either I mean look it's a little bit kind of mushy the texture isn't incredible but if you were to you know give me like a blindfold taste and say did this come from your typical shabbat meal on a black and I would say by the way if I got served this as a shabbat meal I would say it wasn't bad it was like an average chicken cuscus kind of situation I would probably I would never guess that this came out of a box um so for $14 in terms of the portion size you get I've just kind of played up about half but I think you'd really need the whole thing in order to feel satisfied I guess it is pretty expensive but such is the price of kosher meat in the US unfortunately my serving tip as always get some if you like hot things get some lindas hot sauce and you're just going to put some on the chicken and we're going to hopefully bring up the flavor profile a few notches much better um and that's it guys so I have if you're a kosher keeper and you're traveling the USA you can get these in multipacks of like six uh $14 is a bit cheaper if you get them in the multipacks they have a chow main one of which I was intrigued to try this was the bone in chicken the company's called KJ Poultry it's certified black kosher and I try to keep kosher on the road and have some meat while you're at it get one of these things thanks for watching guys hope this video was uh was uh interesting and I try to get more videos about Israel and Jerusalem as the general themes and the occasional review of kosher MREs like and subscribe


RTX 4070, 17-inch display, 12th gen i7 and 64GB of RAM, this bad boy can sweet all that. The MSI Katana 17 has a great hardware selection that will appeal to budget consumers. Going to the 12th gen Intel processors is a smart play as it lowers the price while still getting the latest graphics. The chassis might be made out of plastic but the sheer heft of it keeps it You can also thank the metal bracing on the inside for that. The lid has some lines running along the vertical axis and the MSI logo so the design is still gamery but it's a tasteful execution. For portability you've got a weight of 2.6 kilograms and a profile of 25.2 millimeters which is fine for a 17-inch machine. Most of the base is used to house the 4-zone RGB keyboard with transparent WASD keys, tons of key travel and clicky feedback. The touchpad looks a bit small however the laptop is pretty big too. More importantly it's smooth and very responsive so zipping around the 144Hz display feels good. As far as IO is concerned the left side house is a power plug.  On the right there's a LAN port, an HDMI 2.1 FRL port for up to 8k 60Hz or 4k 120Hz signal output, one USB type C 3.2 Gen 1 port with display port capabilities, one more USB type A 3.2 Gen 1 port and an audio jack. The 17.3 inch display is surrounded by thin bezels except the top one which houses the HD webcam. The display is good for gaming with a 144Hz refresh rate and an IPS panel contrast and brightness are okay but nothing to gloat about. It also only covers half of the sRGB color gamut so if you're thinking about serious design work look elsewhere or get an external monitor. Still programmers will rejoice at all the power this baby brings and so while you're looking at all that code all day why don't you get our office work profile. It's specially tailored to make techs more legible, we'll leave a link to it down below. The sound setup is on the bottom despite there being a small grill above the keyboard. The audio that it produces is good however there are deviations in the lows and highs while the mids are clear. Only 2 per 100 people watching this video are subscribers. If you decide to just start following us we'll be able to reinvest more in our laboratory thus making even more helpful videos for you. Thank you, you're awesome. Now for the combination of Alder Lake and ADA we've got the Core i7-12 650H a 10 core 16 thread CPU as well as the RTX 4060 with a TDP of 105 watts however you can upgrade to the RTX 4070 with the same TGP the processor does well scoring higher than the Ryzen 760 800H and the same Core i7 inside the ideapad gaming 3i from last year. As for the RTX 4060 it dominates 1080p games with ease so even 1440p gaming on an external monitor is possible and a real option here you can check out gameplay at 1080p. Starting off with Metro Exodus a game that's known to make GPUs bend the knee the 4060 is able to run it at 83 fps on the high preset and 40 fps on the extreme preset. You know then we move to one of the better open world fps games that are out Tom Clancy's Ghost Recon Wildlands. The Katana 17 is able to 73 fps on the ultra preset however you can lower the settings if you want to experience the 144 hertz refresh rate properly. Shadow the Tomb Raider allows you to basically play as Indiana Jones albeit without the whip and the cowboy hat. You get a bow and arrow though which is a plus. The game runs great with 93 fps on the highest preset. Excuse me. Yes sir even after the fiasco in brazil no one questions your leadership of the organization. We've come too far to stop now. Yes sir they're ready for anything. Jonah Dominguez is not just the leader. As for how MSI is cooling the CPU and GPU we've got a six heat pipe setup with three heat sinks and two fans it's a robust setup that helps the CPU boost to 112 watts even if it is for a couple of seconds in prolonged loads you can expect 85 watts and speeds of up to 3.44 gigahertz. The graphics card doesn't reach its full 105 watt limit however it still maintains speeds of 2200 megahertz during prolonged gaming sessions while keeping temperatures low at only 73 degrees celsius. Comfort wise the laptop isn't as loud as we thought it would be while the outside remains cool with a hot spot of only 40.7 degrees celsius. We would have wanted to see a bigger battery pack since the 53.5 watt hour unit here only lasts for six hours and 26 minutes of web browsing or five hours of video playback. This is fine for a gaming machine however the battery will drain quicker with more intensive workloads. Going on the inside the katana 17 has good upgrade ability with two sodium slots for up to 64 gigabytes of DDR5 memory as well as two M2 slots for PCIe gen 4 SSDs. For a more detailed teardown check out the video that we've got linked in the upper right corner. The MSI katana 17 is able to deliver that next gen RTX 40 series gaming performance for a lower price thanks to the alder lake processors which deliver a great platform that won't bottleneck any modern GPU. It's also well upgradable while the iO is plenty so we would recommend the laptop if you're in the market for a big boy gaming machine. If you'd like to find out more about this model check out our detailed review on LaptopMedia.com


All right, I think we're alive. We're alive? I gotta fix the camera angle. We need to clean up all this stuff. It's so... Sorry for all the movement, y'all. It's two o'clock, Tuesday. It's up Evelyn, 2-2. Susan, what's happening? How's everybody's Tuesday? Beautiful day here in Dallas, Texas. Tim, what's happening? Land? Hello from sunny Idaho. Welcome Chris Logan. Diana. Karen, Melody. Wow, how's everybody doing today? Susan Campbell, having an awesome day. Oh, the beach book in hand. An ATD on iPad. Nice, very nice. So tell me this, do you guys, rising gals, I know there's a lot of people saying y'all, hey y'all. Do you guys say y'all because we say y'all or do you just say y'all because you say that? Hello from Indiana. Well, hello, Indiana. What beach are you at? Susan? So what we're doing here, Erica painted this, Erica painted this yesterday. Like, can we just grasp that idea that she painted this? Like, look at this. Like, it's so amazing. A lot of shadows in here, so it's been hard to see the detail. Like, camera doesn't do it justice, especially with all this gold, a lot of light. Yeah, I just, we, I know that a lot of people are like in here and I know a lot of people don't say y'all, but since we say it so often, like hoping that we're just rub off on people. You know what I'm saying? What's up, Megan? All right, so I've been starting this for quite a bit. All right, so she made this for, is this black on here? Is this supposed to be here?  Oh, it's not supposed to be on there. I literally just picked it up and showed them. I don't, I have no idea what that is. And I just touched it to see if it was on there. I don't know, did anybody see me put that black mark on there? Cause I don't, I don't have, unless I just touched that, but I don't have anything, I just touched this cup. I'm sure she can fix that. Sorry about that. What's up, Petra? How are you? Andrea, hello, hello. Straping where I had to wipe it off and it folds into the ink. Is that white? Not at all. Back drop. This is another backdrop for a photographer that we're gonna put some circles and one big line through it basically. I cut some vinyl out and it's very, very textured from the spray paint. Oh, this looks great with this gold on here. Very textured from the spray paint. So we're gonna put this coat over it and let it sit. So it's nice and smooth for the vinyl cause you'll be able to see all this texture with the vinyl, especially with the gold cause the gold is pretty thin and it shows every little bump. So what's up everyone? What's happening? Little name, some trash in there. I guess we should put some fire on it. Let's see if there's some heat. What's the rule for the flood coat? I don't know, what's happening? Well, maybe, you know I'm not good at that and I thought you were gonna be talking. So is that what we're doing? We're just doing a flip. I was trying to tell him, I told him that we had to flood coat this cause it was textured. So I don't know how speaking has a lot. It's okay because it's gonna have that decal put on it and then another coat put on it. So the deal with this one is we put spray paint on it and decals will either not stick to spray paint or. That's what I just told him. I told him all of that. Okay, here's a little dry spot right there. Absolutely Tim, hello everyone. You painted your own backdrop so it was going to be kind of nice. There should be some really light halo in this. Like just enough to where it's kind of barely noticeable. Yeah. It would look good. Cause there's one little sparkle in there that looks good. Now there's two, I don't know, I'm not aware. Because everything has glitter in it in our shop. So yeah, this is a photographer that's coming in to town for a jewelry shoot reached out to us for custom backdrops.  This one, that one, and then a little stair step. I think that's good. Thank you, you're correct. So I did for this one. So she did this with alcohol inks and sealed it in with archival sealer. Like a clear matte. And then do this little flip cut over it. So it's nice and shiny. Do you have any resin left? I have a teeny bit. This guy, I want to do a bigger one. I think you should because it's pretty amazing. Judy, yeah, this white one is so nice. It's so soft and classy. Like I'm really digging it. Nice, very nice. This looks great. This would look good too if it was matte. It would look real nice. Why haven't matte UTC? I always remember when you add resin to what you're doing, you're adding bubbles. So get those bubbles out. Get them all out of there. It's so nice. See that gold looks so good. Like that hard edge and then she has it faded out. That's super nice.  Amanda, Rojas, Rojas? Better if I go live using alcohol. It looks like it. You said, hope I don't go live. We do every now and again. She does if she's doing a project or if somebody asks us to. She just went live. Did you do a live video with Rhonda? I'm on her channel. There's gonna be a nice little sample piece there. And it's like, oh my God. I keep hitting this camera in my context. The fuzz in the bottom right corner. There's something right here that's grabbing me insane and I don't know what it is. Nice, very nice. Did someone say fuzz by y'all? Who is that? Lisa Bannister? You still call the police fuzz? It's the fuzz, scram. Scram. I don't know what that is. I don't know how it's making a divot. Like two little spots. Hopefully it'll settle down. I should settle down. It drives me insane. Now it's like more. I can't tell if it's like a reaction. Is there anything gonna go over this? This is done. Maybe another total resin. I don't know. There's just like these little, and it's not coming out. If it's something, it's just there. We'll go on here and see if that fixes it. We're using just resin today. We're using their diamond coat because it dries a little faster. I want to put that sticker on there today and then flood coat that too. Make deadlines. All right. I think we're done with this. What are you working on over there? I'm just putting another layer. Use the rest of what you got. I had to put some on there, so it's like, I might be able to cover the top of that. About it. Let me bring that over here and show them what that is. So they can see that. She painted this thing that she's bringing over here too. So they needed a little stair step type thing to hold like rings for their jewelry photo shoot. And they said they wanted rose gold with depth. And so, I figured the only way to add depth is to airbrush it, which I'm not that confident in yet, or just do layers of the same color rose gold.  These things don't look like they're 24 inches long. That looks so good. It's so fun. It's hard-cutting commission from another artist I consider obviously photography and art form, but they have their own terminology. So converting that into verbiage that we use has been interesting. I'm constantly picking fuzzies or dog hair out of my projects and the dog is in their work close to my studio space. It's probably just on you. For example, we were just balls off and it just gets in the air. We just had to get glitter out of that piece we just flooded. And we're using glitter in mints. So the first flood layer that I did, it was with the stair step the other way. It was laying this way. So now I'm flooding it opposite. Oops, sorry for all the movement. But I'm flooding it opposite so that the depth of the resin is the same on both sides because obviously where it's vertical it's gonna run. You told me last year that I would be doing photo shoot backdrops and such. I would have called you crazy. Pouring on anything vertical is not my favorite thing but I'm trying to pay for a wedding. So I'm taking a lot of odd gigs. Huh? Yeah, flood coating different shapes is not the most fun but necessary. I forget what I'm doing. So yeah, everything that had resin on it that's being flooded was sanded with 220. Did you really put that resin on it? I did. Is it enough? I made way too much in the first layer. You wanted rose gold marble so that is hopefully what I'm giving. Thank you Tim, I think so. Even though just resin self-off-gasses bubbles I always try to hit with a little bit of heat just to make sure that I've picked all the fuzzies out before I get distracted doing other things. I'm gonna try to put a little bit more right there. I don't know if it's a low spot or what goes on but quite fit. Alright, I know this wasn't the most intriguing video but I hope you guys maybe learned a little bit. I know it Bowie. I think Bowie's upset that I haven't he hasn't gotten his screen time for a little while so I'm gonna go grab him one moment. Are you the camera guy for I'm showing you the dog dot? Say hi. Bowie. What do you think? Is it pretty? Bowie, Bowie look. He's looking for you while you're holding him. I said say hi and so we automatically looked at the door. Alright, well thanks for all of 29 of you hanging out with us today so far. I don't know if it's one but what are you gonna do? We bring y'all into whatever it is we're arting that day. That's what today is. Blood coating. Blood coat, boring coat. So yeah, hope everybody has an awesome Tuesday. Going back to packaging fire sale pieces. Fire sale. Fire sale. Yeah.  Remember here at ATD. We do the tests. And I'm gonna say it now. You say that after. Really? Cause you never know what someone's going through. And always remember to ask a question because everybody started out not knowing. I'm gonna start saying that because sometimes people get afraid to ask questions. Ask questions, make mistakes and get messy people. Yeah. So you guys have an awesome day. Be kind to one another. You never know what somebody's going through. We'll see you tomorrow. 6 p.m. Central Standard Time. Wedness Day. Bye. I said bye.


The Ministry of Commerce, International Trade, Investment, Enterprise Development and Consumer Affairs, in partnership with the Embassy of China-Taiwan announced on 3rd November 2020 the very first virtual opening of St. Lucia-Taiwan Business Partnership Week, which is also the broader framework of the annual St. Lucia-Taiwan Partnership Trade Show. This year marks a new chapter of the Trade and Investment Partnership between St. Lucia and Taiwan. Under the framework of St. Lucia-Taiwan Business Partnership Week, three trade and business related events will be held between 4th to 6th November 2020. Honourable Bradley Felix is the Minister for Commerce, Industry, Investment and Consumer Affairs. Over the past decades, the Government of St. Lucia and Republic of China-Taiwan have worked collaboratively towards a shared vision of growth, prosperity and independence of our citizens. We have increasingly sought new avenues for trade, partnership and development in a manner that is both sustainable and mutually beneficial to our island nations, while at the same time encouraging cultural and knowledge exchange in areas of agriculture, industry, technology and beyond. This year's inaugural St. Lucia-Taiwan Business Week is but the latest initiative within the scope of our alliance, with its intended long-term impact being to heighten bilateral trade between our two countries, increase foreign direct investment and to inspire creativity and innovation in the spirit of entrepreneurship and private sector development. This week, through a series of events, virtually and face to face, both in Taiwan and here in St. Lucia, we have focused attention on creating awareness of trading and other business opportunities which exist within our respective borders. The first business related event titled Caribbean and Pacific Islands Tourism Marketing Campaign will be held on 5th November 2020 in Taipei. The exhibition is hosted by the Ministry of Foreign Affairs of the Rock, Taiwan, Taiwan External Trade Development Council and the Embassy of St. Lucia in Taiwan aiming to promote St. Lucia's export products and tourism industry. The two follow-up events are 2020 Partnership Opportunity Delegation Online Conference and a virtual online startup workshop which will both be held in St. Lucia in association with the U.S. Embassy to Barbados, the East Caribbean and OECS. It focuses on attracting investment from Taiwan and the U.S. private companies to stimulate St. Lucia's economy. His Excellency Peter Chen is Taiwan's Ambassador to St. Lucia. Never let a good crisis go to waste. Where others see volatility, we shall see opportunities for prosperity and building global partnership. Taiwan has committed to work with the people and government of St. Lucia and all partners promoting trade and business and people-to-people connectivity. I believe we will wade the crisis together and remain proactive in expanding international cooperation. Business startups and individuals who are interested in these events are welcome to visit the Embassy's website for more information.


Hi and welcome to the session. I am Neha and today I am going to help you with the following question. The question says top surface of a raised platform is in the shape of a regular octagon as shown in the figure. Find the area of the octagonal surface. Let's see its solution. We need to find the area of the given octagon. So for this first of all we will split the octagon into two trapeziums and one rectangle. As I have done in the given figure by marking two lines this one and this one. Now let us name this octagon A, B, C, D, E, F, G and H. Now we have a trapezium A, B, G, H. Second trapezium C, D, E, F and a rectangle B, C, F, G. So to find the area of the octagon we will find the area of two trapeziums and a rectangle and we will add all these three to get the area. So let us write area of octagon A, B, C, D, E, F, G, H is equal to area of trapezium A, B, G, H plus area of trapezium C, D, E, F plus area of rectangle B, C, F, G. Octagon that means trapezium A, B, G, H and trapezium C, D, E, F are congruent. That means their area will be equal. So let us write we have trapezium A, B, G, H is equal to area of trapezium C, D, E, F. So that means we just need to find the area of one trapezium and this will give us the area of other trapezium also. So first of all let us find out the area of trapezium A, B, G, H. So we will write for trapezium B, G, H length of B, G. So H will be equal to meters. So H is equal to 5 meters given to be 11 meters. Now the distance between the parallel lines A, H and B, G let us call it equal to 4 meters of trapezium 1 by 2 into 10s between these two parallel lines B, G. Therefore trapezium H is equal to 1 by 2 into B, G into H. We will get 1 by 2 into 5 meters. So for rectangle 11 meters that area of rectangle is equal to length. So this implies equal to length that is B, G into breadth that is that is equal to 5 meters square B, H that is 32 meters that is 55 meters square. So this is equal to therefore area of octagon is 119 meters square. Yes we finished this session. Hope you must have understood the question.


Hey guys, but you're wondering what the heck that is on camera This is another video for art joy of sharing this month. We're talking about mark baking tools So here's something not a lot of people know about me. I have been and still do collect homemade mark making tools and I have since my first beginning journey into mixed media and My baskets occasionally need to be purged because I save way too much stuff to make marks with and then I have no room in the two bins for anything else We're going to go through some of them. What's in my bins and we are going to I'm going to share with you some of my favorite things that I have that I've used and Where I got them how I acquired them Hopefully to give you some ideas of things that you can save that you maybe even have around the house things that you think are trash That you can use to make marks with in your work So let me move one of the baskets or both because we cannot get them both on camera at the same time They are huge. Okay So here's one thing now this I picked up at an art salvage place when I was in North Carolina not long ago And it still has the tag on the back. I haven't used it yet, but this is a piece of plastic canvas And this is great to put on a page and then say spray your spray or acrylic sprays through or inks or Something like that. It makes a really nice mark Plus you can put it on your jelly plate Press it into the plate and then take it and and use it use on the jelly plate as sort of an ink pad to get Paint on here and then put that on your journal page to make a mark Plus it leaves a nice mark on the jelly plate that you can transfer to paper. So Plastic canvas is really great. I Don't remember where this came from somebody might have sent it to me, but it's the same idea It's a plastic-y canvas kind of material, but it's diamond patterned. This is cardboard This is cardboard packaging from something that we bought. I don't remember and I've had some of this for a long time Here's another piece that I glued to some regular cardboard. You can see this is well-loved These make great marks on paper and journal pages. Can we get that in camera? Yeah, maybe Alright Here's some more plastic canvas is what I'm talking about. So I love you can see this one's very well-loved So I love the plastic canvas this one happens to be circular so you get a little bit different shape with it But it's really great This is a Martha Stewart brush that is So sometimes you see old dead paint brushes in here that brushes are These are dead But they're stiff and hard with paint medium, but they make an interesting mark on The page through the paint. So even your old say you have a brush that you forgot to wash and it just dried up It's like a rock, but maybe if you drag it through or scratch it through some wet paint It's gonna make an interesting mark. Don't throw it away right away Anything that's around Lit with lids Without lids. This is a old prescription bottle from my dog that passed away Yeah, this is banded. This is galliprant And not only does the bottle make good marks, but the lid too you also can use the bottom or the closed lid to make marks This is from I don't remember what it's from something that we bought But it was just garbage. It was part of that, you know product packaging and it makes an interesting mark This is a from the dollar store and this is I think to clean like your fingernails Or something at the sink, but Here's another piece of that cardboard Different kinds of fittings. This is actually a nail art tool From Wish. I think this is a back massager thing again from the dollar store Piece of a silicone potholder You don't need the whole thing So one thing a couple friends of mine and I did was we got some of these silicone potholders And then we cut them in halves or in fourths Because we really only needed a little piece to make a mark on our jelly plate or our journal page We didn't need the whole thing and they come in a number of different patterns Now you will see a lot of homemade stamps before I started Manufacturing my own stamps. I made stamps out of craft foam I got the thick craft foam for the base and then the sticky craft foam to cut the shapes out of There's a bunch of those in here. This is one that I carved out of rubber There's a bunch of those kind of things in here More plastic canvas Here's the piece of just plain cardboard like from a box from Amazon I peeled away some of the top layer not all of it to reveal an interesting texture Then I could put paint on it and push that on a journal page. It makes an interesting Textured mark. This is This is the leftover piece of bolt from a hobby lobby Some kind of trim. I don't remember what kind of trim it was but when I bought it I said can I have the Bolt and they said sure Do you know why can you see why it again makes interesting marks What else do I have in here? This is I haven't used this yet. This is a base plate for Legos So here's another sort of plastic canvassy thing is the squares These are nonstick Like table shelf table runner shelf things the nonstick like plasticky fabric you put under stuff So it doesn't slip around and they make interesting marks We have a Game of Thrones clue game and when we were putting it together and getting ready to play it We pulled a bunch of things out of this and I saved it Wouldn't this be interesting to painter stencil through painter stencil through this painter spray through These are from some Christmas lights Again, they would make interesting marks to spray or paint through or to use on any of these could be used on the jelly plate Here's more that non-slip stuff These are some rubber like bookmarks from our local library. They're textured So they would make interesting marks bubble wrap This is a makeup cleaning thing That you can use to make marks with or clean your paint brushes This is a art supply tool that has different teeth on the edges that you can use to scratch through your paint So it's in here because it's a mark making tool, but you could make this out of hard plastic or cardboard What's that? That's the center to your roller scotch tape So again, it makes interesting marks Here's some more of that cardboard pipe fittings nylon shower things Giant chess pieces Here's one. This is um These are ice cream lids glued to cardboard They make it again interesting mark making tools on jelly plates and stuff Here's mini rolling pins covered with things like rubber bands and you can roll them on your jelly plate plate Get them covered in paint and then roll it on your journal page And then you can still take your paper to the jelly plate and get an interesting print from this More of the silicone potholders. Here's another mini rollie pin covered in bubble wrap This is from the inside of a ball of yarn the foam This is from the inside of Cash register paper. I was at the store one day and they were changing it out and I said can I have that plastic thing? Yes, I did actually say that. Here's more of the silicone potholders I also have like a jar full of little things here in the bottom another prescription jar Which in its own makes interesting marks, but then it's filled with things like these plastic washery things that came in product packaging and Metal washers, there's some can you see I Don't know if you can see but there's some tile spacers in there They all make interesting marks either on the jelly plate or your journal pages Okay, what's the but what's that? Do you know? It's the bottom to a cane So that's what I'm telling you. There's a lot of stuff in here. I don't remember what these are from They're called sticklets. I don't remember what what they're actually for but again interesting mark making tools The bottom of a flip-flop a plastic placemat Piece of one more cardboard. This is just cardboard with littler cardboard in between to space them out And what else do I have in here that might be interesting here's an old comb So the idea is oh here we go, that's a hockey puck or Ice rink, I don't know. It's something from the heart sports storm More plop pipe fittings Sponges here we go. This is one of my favorite tools. I've been using it for years. It's a big giant foam die from Dollar at the dollar store So my point is you don't need to spend a lot of money to find interesting mark making tools You can get things Inexpensively you can repurpose and recycle what would otherwise be trash So look around you and see what you have that's adventurous and interesting that you might be able to make interesting Marks with as you find something new and unique that you think we might all be interested in leave it in the Comments below share your favorite thing and Let's start a conversation. You can do it here. You can do it in over an art joy of sharing We would love to know what your favorite mark making tool is. Maybe put it with picture with it and Reassure me. I'm not the only one with a hoard of mark making tools Maybe please. All right, that's it for today. I hope that you check out the video description Don't forget to like share and subscribe All of the artists and art join sharing are bringing out videos this month with their favorite mark making tools So don't forget to show them some love support your favorite artists and youtubers as you can Most of them will have something in their video description. So check it out Whether it's patreon a PayPal tip jar or something we all would appreciate you doing that and Above all go out and have a great day. Do something nice for yourself because you deserve it and we'll see you later Bye guys


T F N N headline news update Welcome folks. We have the Dow industry is up 27 Nasdaq is down far the S&P's up four and a half gold gold up $2.70 trading at 14 90 and outs We had silver down seven cents 17 dollars 53 cents an ounce light sweet crude up 85 cents 54 dollars 16 cents a barrel notes and bonds you get the 10 year up five ticks 129 25 the 30 year up 20 at 160 to we're gonna go over to the 10 as well as the 30 folks. This is Right now these are screaming for higher price and when you take a look at this This is serious business. Okay, you don't see this a lot and what I'm gonna show you here It has to do with the tenure the tenure loves doing 1.6 1.7 2 million contracts a day Only did 902,000 contracts you're going against 2.4 million contracts and we continue to reject lower price with tremendously light of volume That's telling me these things are gonna go top side of in a huge way not in a small way That's a 10 year that wants to get up to the ties again of 1 32 13 You have harmony in the marketplace inside the debt market and the 30 years doing the exact same thing Bottom line the 30 year and I check this out. This is pretty cool the 30 and it's seven eight more ticks right now and I to get a full rejection of The lows that were established out here on September 13th So we've done 199,000 contracts. You're going at the 460. You hit 150 902 today or 150 931 160 7 is the number you get above 160 7 that thing's gonna be a rocket ship going all the way up to 166 25 King dollar King dollars gets a movement out here today You had two Brexit votes first one passed second one didn't pass moving everything around a bit dollars up by 201 ticks trading at 97 53 if we go take a look at the spy What you're gonna see with the spy bottom line spies backing off Got to a price point that if 390 so you what you're gonna have is this you can have a higher high Light of volume rejection of price market wants lower price and the x100. That's the one that really stopped moving things out here As well as the composite this morning on the way down. Would you have the end the x? This is pretty intense also is that you're actually we're trying to get into the highs of last week, which is the 194 50 couldn't handle it you down a buck 10 you're at 192 29 stay right there folks coming back last 60 minutes of trading You can expect some action and these last minutes when most of the day we've been moving sideways You get some big numbers out here though. It looks to me like we're gonna have some selling coming at their clothes come right back


Welcome back to this lecture series on Cathodic Protection Engineering offered by NPTEL online. In this lecture on stray current corrosion and mitigation we will be looking at the following aspects that is what is stray current corrosion in buried structures. We have seen in the beginning when you talked about the external corrosion of buried structures, stray current corrosion is one of the main problems that affects the structural integrity of these pipelines and storage tanks etc. The stray current corrosion also is an important problems in offshore structures especially the ship hulls. So, we look at what do you mean by the stray current corrosion in details. Then we will also look at how to detect stray current corrosion in these structures. You remember that these structures are buried, they are not visible to the naked eyes. So, how do you really detect the stray current corrosion occurring in these immerse or buried structures? Once we know that the stray current corrosion is operating and the principles of stray current corrosion, we should be looking at how to mitigate the stray current corrosion occurring in these structures. Lastly, we will be covering the topic AC interference and mitigation. We will notice that AC interference is a major problem in terms of safety hazards, but it can also lead to corrosion issues. So, in this lecture we will be focusing more on AC interference in as related to corrosion of the structures. Before we discuss stray current corrosion, let us go back to the cathodic production in general. What is shown in this diagram is schematic of cathodic production of a structure involving anode and a cathode and of course, a source which is a DC source a rectifier. I have used this here rectifier because the stray current corrosion is mostly occurring when the structures are protected using impressed current cathodic production system. We will see the reason also very shortly. So, coming back to this cathodic production of the structures, you notice that the source the current source the anode dissipates current in the soil and then the current travels to the cathode and again goes back to the rectifier. Now, this is the path of the current flow in a normally cathodically protected structures. So, this current flow can be given in terms of a simple equivalent circuit given below here. It is consist of several resistors, resistances offered by let us say the cable here, the resistance offered by the cathode, the resistance offered by the electrolyte and then the resistance offered by the anode. If you notice that all these resistances are in series. So, they offer resistance for the flow current in the cathodic protection of engineering structures. So, what happens if there is a foreign structure close to this cathodic protector structures. So, let us see that we shall now see what happens if there is going to be a foreign structure lying very close to this cathodically protected structures. In this slide on the left side a schematic of the cathodically protected structure on the foreign line that is passing through the structure is given. On the right side an electrical equivalent circuit of the same is provided. Let us look at the schematic of. So, let us look at the schematic given on the left hand side of the diagram here. So, let us examine what is happening in a system where stray current corrosion occurs that is illustrated skip that is illustrated schematically using this diagram here. We have seen in the previous slide that the cathodic protection system typically consists of an anode, a cathode and a rectifier and the current in this such a case completely travels from this anode to the cathode that is cathodically protected structures. In the case of a foreign structure like a pipeline which is passing by in the in the in this vicinity then a part of the current that leaves this anode enters the foreign pipeline. When the current enters from the soil on to the pipeline you know that this location becomes a cathode. It is very much similar to the structure which is intended for cathodic protection. So, the current enters this pipeline it travels along the pipeline. Now, you notice that the metallic structure has a least resistance compared to the resistance offered by the soil. So, the current easily flows along this metallic structures and this current flow is through electronic conduction. Now, this current flow cannot continue forever because the current has to go back to the circuit and to rectifier. And so, when the current goes or the when or when the current travels very close to the vicinity when the current travels very close to the vicinity of the buried structures the current tries to leave the structure and enters the soil and from there it enters the intended cathodically protected structure and then goes back to the rectifier. So, you notice that a major part of the current however goes to the structure which we wanted to protect. But a part of the current again enters into the foreign structures. As we discussed earlier the when the current enters a pipeline that becomes a cathode it does not lead to any corrosion. However, when the pipe where however when the current leaves the pipeline into the soil there is a transformation from electronic conduction to electrolytic conduction here and as a consequence there is going to be electrochemical reaction and so, there is going to be corrosion taking place. As you notice that this place acts as an anode much is similar way the anode that is intended in the cathodic protection systems. So, there is a corrosion occurring in the foreign line in this vicinity leading to corrosion damage and this is called as stray current corrosion because a part of the current that has intended to go into the protected structures, stress into this the foreign structures and then goes back to the circuit. When it goes back to the circuit the corrosion occurs at the location where the current leaves the structure. So, this is the concept of the stray current corrosion occurring in the in the foreign structures. Now, the same thing is now given in terms of the same thing is given in terms of erentically equivalent on the right hand side here. You have a current source which is rectifier this current source faces the resistance of the cable, cable resistance, the anode resistance and the soil resistance the cathode in a normal cathodic loop protector systems where there exists no external pipelines. So, there be an external pipelines as you seen here the current again stays from this anode and goes into the structures and there is a resistance offered by the soil that is indicated over here. You can see that the resistance this is the resistance offered by the soil. So, what fraction of the current or what fraction of the total current enters into this into this structure depends upon the resistance offered by the soil over here and over here ok. So, that is the total resistance offered by the soil for the stray current to enter the metallic structures. Notice again the metallic structures are highly electronically conducting it virtually does not provide any resistance for the flow of current. So, this is the concept of stray current corrosion. To summarize what the stray current corrosion is that whenever you have a foreign pipeline or foreign structure they lie in the vicinity of the already cathodically protected structures a part of the current from the anode enters the foreign structures. The place of entry for this structure becomes a cathode and where the current leaves back to the circuit that becomes anode here. The place where it becomes anode the pipeline suffers severe corrosion and the extent of corrosion that enters the pipeline depends upon the resistance offered by the soil over here that is between the anode and the foreign pipeline and the pipeline on the buried structures. So, that is the principle of stray current corrosion. Now, why we should be worried about stray current corrosion? Let us look at this data given here it is an indication right it is an approximate indication of what will be the effect of stray current corrosion on a pipeline or a buried structures. Normally, the pipelines will have a corrosion current density in the order of 10 micro ampere per centimeter square and if the structure happens to be of 5 millimeter thick and it is allowed to corrode the structure will last 20 years for the leak to commons not of course considering any mechanical effect because when you reduce the thickness of the structures and there are internal pressure like hoop stress there can be early failures assuming that the mechanical effects are not coming to clay it takes about 20 years for the structures to leak. On the other hand for a stray current corrosion if it is of the order of let us say 10 milli ampere per centimeter square it will just take about 6 days to leak. So, that is the effect of stray current corrosion we should be worried about. Now, let us go to the real-life situations. Let me describe 2 cases or 3 cases to make you understand how the stray current corrosion occurs in practice. What is shown on the left side is corresponding to the pipeline and what is shown on the right side is between a tank and the pipeline here. In the left side the pipeline given in the green color corresponding to the one which is cathodically protected using rectifier and the anode bed anode ground bed here. As you notice that the the current is intend to go into protecting the structure here right, but a part of the current can travel into the soil and enter a pipeline which is foreign to this particular pipeline and this pipeline may be protected cathodically may not be protected cathodically is possible right. So, as you notice that this pipeline where it receives a current it becomes a cathode and it the current in this travels along the pipeline when the current reaches closely in the intended pipeline it jumps from the pipeline unto the soil and you see that there is going to be dissolution over here. And of course, the intended pipeline here does not corrode because the intended pipeline receives the current it is cathodically protected right. And as you see the point A and point B they suffer the corrosion problems and so as the point D and points point C because it is still possible that some of the current travels over the pipeline here and again tries to return back to the circuit. What is shown on the left on the right side what is shown on the right side is a cathodic protection system of a tank using the press current cathodic protection systems and anode and there is a foreign pipeline going very close to the steel tank right. And again a part of the current leaves this anode and enters this pipeline and again when the pipeline nears the steel tank it is you know when the pipeline nears the steel tank you would expect the current that travels in the pipeline jumps into the soil and leading to the corrosion. So, this normally occurs in the plants because the storage tanks are all located in the in the plants whereas the one which shown on the left side are all for the cross country pipelines or other pipeline networks not necessarily belonging to any plants. Let us look at another example which in fact is a very important example that happens in the metros where there are electric DC traction systems. Now what is shown in this diagram is a locomotive driven by a DC current right and you have a substation a current leaves the substation here and goes through the warren cable and it does work in this DC engine and the current now from this engine leaves the railway tracks. And along the railway track the current is supposed to travel because it is a steel one right it is offers least resistance for the flow current it offers least resistance for the flow of current it should go back to substation. So, the current in a normal course of time is expected to travel from the electric substation to the locomotive right and then it is supposed to return back through this railway tracks this rails because it is electrically conducting. However there is leakage current that leaves this rails and enters the soil and from there it enters the pipeline. Now the pipeline is electrically a good conductor it allows the flow of current much easier and then it travels along the pipeline. But here again that the current cannot travel indefinitely it has returned back to the electric substation. So, when the pipeline nears the substation at that location you see that the current leaves the pipeline and enters the substation. So, that is going to be corrosion at this location because the current leaves the pipeline we define the anode is the one where the current is leaving we define cathode is the one where the current is entering and so that is going to be severe corrosion. Let us look at the sum numbers assume that the current per track is about 2000 amperes is required for to drive this electric vehicle right and even if you consider that about 5 to 25 percent of the current is leakage current that enters the soil and then to this pipeline you notice that about 100 to 500 amperes of current enters this pipeline. As a consequence you notice that at this location a large amount of current is leaving the pipeline and so it suffers a severe amount of corrosion. Now with this kind of current you notice that we have about 9 to 11 kg per ampere year is the kind of dissolution that can happen onto this place and so you can have very quick leak happening on these pipelines. This kind of corrosion is a dynamic in nature because this occurs only when the rail passes through this and then other times you do not have this happening. This is different from what you have seen earlier where you have a static stray current corrosion because here the stray current corrosion occurs all through the day. As opposed to this you have stray current corrosion which is a dynamic in nature. There is another kind of stray current corrosion which is different from what you have seen so far assume that there is a coupling here that joins two segment of the pipelines and if this happens to be offering higher resistance then what happens is it obstructs the normal flow of the current. So, as a consequence the current leaves this pipeline into the soil and again it re-enters the pipeline at other end where the current leaves the pipeline suffers corrosion. Of course, here there is not a problem because it becomes a cathode. It is also important to notice that when you have such a resistive coupling you can also have internal corrosion because the current also can jump within the pipeline. So, the internal corrosion can occur when you have a resistive coupling in in the pipeline due to stray current corrosion. It is important for us to know what the sources that causes the stray current corrosion because by knowing that we can easily mitigate the stray current corrosion. The stray current corrosion can occur for two types of systems one which is static in natures and other one which is a dynamic in natures when you say dynamic is a plant dependent. And the static systems are like between the cathodically protected systems and a foreign line that we talk about or we also have high voltage DC power lines that is which are traveling along the internal structures. In the dynamic systems there are several of them actually some of them are quite obvious like electrical railways, the transit systems, other electric transit systems. You also have some equipments using direct current they involve mining, welding, electroplating, battery charging with ground falls and you also can have high voltage AC power lines. We see later that a separate topic high voltage power lines they do cause stray current corrosion, but the extent of stray current corrosion due to high voltage AC power lines are minimal as compared to high voltage DC power lines. You also have natural geomagnetic or called as telluric currents which cause the stray current corrosion problems. We have just now discussed the source of stray current corrosion. Let us move on to the next important topic that deals with the stray current corrosion that is detection of stray current corrosion. I hope you will recollect one of the lectures we talked about surveys to find out how the underground pipelines suffer corrosion. How do you detect the location where underground pipelines are suffering corrosion? We used two techniques one is called close interval potential survey, the other one is line current measurements. We will see that how these two techniques can be used to determine the location or to detect the location where the buried structures suffer the stray current corrosion. Please notice that these are buried structures it is not possible to inspect by visual means in order to understand how stray current corrosion is detected. Let us look at this diagram wherein the steel tank is protected cathodically using impress current systems there is an anode here and there is a foreign pipeline which is in the close proximity of the tank and there is a stray current corrosion over here and of course, the current where it enters the pipeline it is the pipeline is rendered cathode right. Obviously, you will notice that when the current enters the pipeline here it causes a shift in the potential of the pipeline because there is going to be an electrochemical reaction as a response to the current that is flowing onto the pipeline. So, there is a change in the potential here. Also as a consequence more current is flowing in the pipeline between this segment and this segment. When the current leaves and this location acts as anode so, the pipe to soil potential over here is going to change. So, the pipe to soil potential at this location corresponds to a cathode and the pipe to soil potential at this location corresponds to the anode. So, that is what is given schematically in the diagram here ok and you notice that this in this axis the top corresponds to the anodic potentials and the bottom corresponding to the cathodic potentials you notice that in this location the potential is more negative and the potential remains same because no additional current enters here it remains almost the same. As you notice as you approach the tank the potential tends to become anode and then again the potential drops. So, close interval potential survey can detect the stray current corrosion where it enters and where it leaves a structure. It is also possible to measure the line current and what is given here below in this schematic is a line current between these two segments of the pipelines. As you notice that at this location there is more cathodic current right because the current is collected by the pipeline because of the stray current here and then the current turns anodic because the current leaves this structure here. So, it is possible to detect the stray current corrosion using the two techniques simple techniques which is close interval potential survey and the line current measurements. Of course, between these two techniques the close interval potential survey is simpler let us now move on to mitigation of the stray current corrosion. One of the ways to mitigate stray current corrosion is you have a distributed anodes so that the field around the anode is decreased. So, instead of you know a single anode to cover large area of the cathodic production of the pipelines we can have multiple anodes distributed over a distance right and this reduces the stray current corrosion to a large extent because they can lower the electric field in the soil around the anodes. This is required because in a typical rural areas you know even a single anode grown bed can protect pipeline over a distance of 100 kilometers long distance. It can keep the pipeline negative enough to protect cathodically. In the city however the pipelines are congested there are other foreign structures interfering with the flow of current as a consequence stray current corrosion becomes very predominant. So, the distributed anode system lowers the stray current corrosion very significantly without wasting much of a power. Therefore, the use of distributed anode ground bed systems minimizes stray current corrosion and also reduces the power wastage to effectively cathodically protect the given structures. There is another method of controlling the stray current corrosion is to offer resistance. We have seen that using the electrical equivalent circuit that the resistance offered by the soil between the anode and the foreign pipeline and the foreign pipeline and the intended structures decides the extent of stray current that enters the foreign lines. Therefore, one of the ways to minimize stray current corrosion is to provide high resistance path for the flow of current. So, what is shown here in this diagram is a pipeline which is cathodically protected right and there is a foreign pipeline which crisscrosses the cathodically protected pipeline and so, you would expect that the stray current that entered this pipeline will leave the pipeline here causing corrosion of this foreign pipeline. So, in order to minimize this in high resistance polymeric coating such as polypropylene coatings can be applied on this pipeline. Now, to what distance we would apply this coating depends upon the electrical field of influence between these two pipelines. So, that is to be determined so, as to decide to what length or what segment of the pipeline requires to be coated with the organic coatings or the paint coatings. As you notice here a good polypropylene coating can reduce the stray current corrosion to about 0.001 percent. So, that is a significant drop in the corrosion of the pipeline due to stray current corrosion. But however, what are the issues? However, there are some issues when you use this coating to prevent stray current corrosion. In the case of small defect occurring any of these locations you would expect that the current will be localized and so, there will be severe corrosion occurring at that location. So, in order to reduce this it is essential to coat the other pipeline as well if it is not been applied with any coatings. So, that the resistance offered by the other pipeline also deters the current from leaving the pipeline. We have shown earlier that stray current corrosion occurs because of change over from electronic conduction to the electrolytic conduction right that is where the current leaves the pipeline and enters the soil the corrosion occurs. If you can avoid this electrolytic conduction then this stray current corrosion can be avoided that is shown in this diagram here. You see there is a tank which is cathodically protected using two anodes here schematically shown and there is a rectifier to supply the current. As you notice that the part of the current from the anode enters this pipeline and travels through and we expect the stray current corrosion to occur over here. So, instead of allowing the current to transform from electronic into electrolytic conduction right you can use an insulated connection electrical cable between steel tank on the pipeline the current leaves the pipeline through the cable and thereby avoids the corrosion of the foreign pipelines. So, it is very simple. So, what is the problem here? The only problem that one would encounter is that in such a case this segment of the pipeline that you notice here will be cathodically protected at the expense of the current provided by this rectifier and so, one spends the power to protect the foreign pipeline. So, in order to minimize this power consumption to protect cathodically the other pipeline one uses a resistor. So, that is shown in this diagram here on the right side wherein the bonding between the electrical bonding between the pipe 1 and pipe 2 is done through a resistor. So, this resistor can minimize the flow of current. However, it is important to ensure that the value of the resistance introduced here is not so high that it prevents the flow of current through this electrical bond and encourage the flow of current from the pipeline onto the soil directly. So, in order to do this the resistor is adjusted such that the pipe to soil potential of the foreign pipeline and the pipe to soil potential of the cathodically protected pipeline are very much closer to each other. So, by using a reference that I showed and a voltmeter you can measure the pipe to soil potentials at both these locations and ensure that they are almost close to each other. So, that the driving force for the flow of current through this rectical bond is minimized. We have so far seen three types of mitigating the stay current corrosion. One was using the distributed anodes so that the electrical field around the anode is very minimal. The second case we used coatings in order to offer very high resistance for the flow of current. In the third case in the third case the electrical bonding was done in order to avoid electronic conduction and transfer the current from the pipeline and to the internal structures directly. The stay current corrosion can also be minimized using another concept called as electrical shield that is schematically that is schematically shown in the diagram. As you notice this pipeline is cathodically protected using rectifier the anode over here and in a normal circumstances the current will leave these anodes and stay into this pipeline and somewhere else it will return back to the pipeline causing the stay current corrosion. Now surrounding this anode the field is so large. So, if you can use a metallic collector it could be a another metallic pipe surrounding this the foreign pipeline and electrically connect this pipeline with the rectifier. The current that travels from the anode gets collected by these collected and returns back to the rectifier. So, major part of the current is not going to enter the pipeline. The stay current corrosion is significantly avoided at the source of current itself. There is one more way of minimizing the stay current flowing into the pipeline is by installing sacrificial anodes at a distance from the collector. You notice that the sacrificial anodes have much more negative potential as compared to the pipeline. So, the current drains into the soil here and returns back to the circuit. Thereby you can minimize the stay current corrosion traveling in the pipelines. The stay current corrosion of the foreign line can be controlled by installing a separate cathodic protection system for that particular pipeline. One can use a sacrificial anode installed onto the pipeline and so the corrosion at this location can be very much minimized. There are other effective ways of controlling the stay current corrosion is to relocate the anode ground bed. Suppose we have pipelines which are traveling parallel to each others and if it is possible to relocate the anode ground bed such that the anode ground bed is shifted far away from the indenter pipelines then the stay current corrosion entering the foreign line becomes minimal. We have seen earlier the stay current corrosion in the DC traction system is very severe and it requires to be controlled without which the pipeline can corrode very quickly. And this is done by using almost all the principles we discussed so far. We see that now one after another. First of all we understand that the current that returns to substation they travel through the rails. As a first attempt to minimize stay current corrosion the electrical resistance of the rails must be reduced. Wherever there are mechanical joints there has to be electrical shorting has to be done using the cables and when these are welded it is less of a problem. The other attempt to the second method is insulate the rail from the earth using very good insulators may be a concrete better than the wood. So, that the amount of current that stays from the rail into the soil into the ground becomes very minimal. After attempting these two to minimize the stay current corrosion it is necessary to control the stay current corrosion at the drainage point where the current is returning back to the substation. Over here we use the electrical bonds short the pipeline with the rail. So, that no electrolytic conduction happens there is going to be electronic conduction the current enters into the rail and then to the substation and do not cause any stay current corrosion. However, there is a problem we notice that the deceased action systems is dynamic in nature. So, when the rail is not there the current may start flowing. We have seen earlier the stay current corrosion in deceased action system is dynamic in nature. That means, the stay current corrosion at the location occurs only when the train passes through that location. The remaining time it is likely that the DC current from the pipeline can enter the rails. So, the disturbing the cathodic protection systems of the intended structures that requires to be avoided that is done by having what is called as a reverse switch. The constituents of the reverse switch is shown schematically in the diagram here. As you see here that the reverse switch consists of a diode that is in series with the electrical bond that you connect between the pipeline on the railway track. And this diode does not allow the DC current to flow from the pipeline onto the railway track. So, that way it reduces the flow of DC current from the pipeline onto the railway track. It is also possible to have an electromagnetic relay so that you can break the circuit whenever the train does not pass through this segment of the pipeline. So far we discussed stay current corrosion occurring in buried structures buried in the soil. Stay current corrosion can also occur in offshore structures. We will use ship as an example to see how stay current corrosion can occur in offshore structures. So, stay current corrosion always occurs because some part of current leaves the structures into the electrolyte be it a soil or be it water. As you know that current cannot travel in the electrolyte in the soil indefinitely and can enter a nearby structures nearby metallic structures. And the metallic structures again is a good conductor of current. The current travels along the metallic structure and when it encounters the main body then the current leaves the metallic structure gets into the electrolyte or the soil and again enters the main body metallic structures which is cathodically protected. In the case of ships we know that the ships are driven by the propellers. The current that leaves from the ship hull enters the electrolyte and from there it enters the propeller shaft which is very close to the ship hull. Because the propeller is metallic and highly conducting the current travels along the propeller shaft and then it goes till the end where you have the blades. These blades are in the close vicinity of the radar and so on that location the current leaves the propeller system and then tries to enter radar and through radar it goes back to the source. As you notice that the current leaves the blades and that location becomes anode and causes the corrosion. This happens because in a normal circumstances the shaft is electrically isolated right. So, in order to minimize this state current corrosion these propeller shafts are grounded using silver graphite slip ring which makes inertial contact with the main body and so the current travels through the slip ring and back to systems. The state current corrosion is mitigated. We shall now summarize various mitigation technique to control state current corrosion. We can relocate the anode bed or structures to minimize the current that enters into the foreign lines. You can have distributed anode systems. We can also re-adjust the current at the source if possible. You can enhance the cathodic protection of the interface structures, install additional cathodic protection for that. We can also have sacrificial anode installed in the pipeline in the foreign pipeline which will act as a drainage points. Provide a reticle bonding we also seen that providing a reticle bonding can lead to excess current drainage from the main source. So, you can also have a resistance installed in the systems and again when you have reticle bonding a regular inspection is needed because in the event of a reticle bonding snapped then there will be state current corrosion. Under dynamic state current conditions we install diodes in order to minimize the current traveling from the pipeline on to the structures. Let us go to the last topic of this lecture AC interference. The AC interference with the intended pipelines or structures can have two consequences. One, it can affect the corrosion of the pipeline or the structures, it can be hazardous to the life. The very interestingly the AC corrosion of the steels can occur even if the half potential is less than minus 0.85 volt. What does it mean? One may measure structure to soil potential let us say even minus 0.95, one would expect that the pipeline is free from corrosion or the corrosion of the pipeline is significantly reduced but that does not happen if there is AC interference. The presence of AC current can also damage the coatings. From the corrosion point of view these two are very important. From the point of view of hazard there is another issue. Let us now look at the source of AC for pipelines. The AC current is due to overhead high tension power lines. Now we have a buried structure or above ground structures over which we have high tension power lines, AC power lines are transport a conduct the current. There are three means over which the current is induced in the pipeline. One, it can be capacitive between the high tension power lines and the above ground pipeline. There is a capacity effect if the voltage is very high at certain circumstances it can and build up aortic static charges and the AC current can enter the pipelines. The AC current can also enter the pipeline through electromagnetic coupling. Now this can happen if the pipeline is above ground or below the ground. As opposed to the capacitive coupling it happens only when the pipeline is above the ground. Now the current that so entered the pipeline will go into the ground and that is due to resistive the resistance offered by the pipeline. And in this case the current flows mainly through the defects the coating defects in the pipelines. So, what are the factors that affect AC interference? From the point of view of corrosion you notice that the AC is generally not lead to any electrochemical reactions. We know that the current is alternating and so AC does not lead to any electrochemical reactions in general. However, there is a concept called Faraday rectification that is asymmetry in the beta A and beta C values leads to some kind of rectification occurring at the interface that leads to partial conversion of AC current into DC current. Very interestingly if the current the AC current is lower than 20 ampere per meter square it does not lead to any corrosion that means the rectification does not occur. You do not get large amount of DC current or any significant amount of DC current to cause any corrosion of the pipeline. Between 20 and 100 ampere per meter square it is little unpredictable that would depend upon the other conditions that you see shortly. If the AC current exceeds 100 ampere per meter square the corrosion is really expected. You compare this current AC current versus the DC current around 100 ampere per meter square you do not expect significant amount of corrosion. On the other hand if you have 10 milli ampere per centimeter square DC current on a pipeline we note we saw earlier that the pipeline will suffer leak in 6 days if the thickness of the pipe is about 5 millimeter. So, you need a large amount of AC current in order to for the pipeline or steel structure to suffer corrosion because only a fraction of the AC current is converted into DC current. What are the factors that affect AC interference they are listed here? As we notice that AC interference has two components one is corrosion other is the safety involved to the personnel who come in contact with these structures when there is presence of AC current in the structures. Now, the AC interference would depend upon the factors listed here the first is the soil resistivity you know that lower the soil resistivity the current can drain out much easier. So, higher soil resistivity can lead to more AC interference. Of course, the AC magnitude of the current that is flowing in the pipeline in the normal circumstances the separation between the pipeline and the power line is important we have seen earlier that the AC interference comes because of both electromagnetic and as well as the capacitive natures. And so, the distance between the pipeline and the power lines are very important as the distance increases the extent of AC current entering the pipeline decreases and the magnitude and duration of the fault current sometimes the current also increases right. So, the extent of increase in current momentarily how much time the current is at high value decides the extent of AC interference with the pipeline. The grounding characteristics a well grounded success will drain the current much easier the nature of the pipeline coatings and also whether the pipeline that we talk about is cathodically protected or not very interestingly the interference corrosion is less when the pipeline is cathodically protected. So, let us look at the last important aspect of AC interference that is mitigating the AC induced voltage and thereby AC induced corrosion. It is important to know that the AC interference is not a problem so long as it does not cause a voltage greater than 15 volt less than that is not safety hazard. In order to reduce AC interference a good electrical grounding is very important in this case a grounding is done by zinc anode and the magnesium anodes. Notice that zinc anode and magnesium anodes have OCP that is open circuit potentials or the natural potential is much lower than that of the steel pipeline and so they become easy drainage point for draining the AC current right. Now zinc anodes are used normally but if zinc anodes are passivating certain conditions the magnesium anode is used we know that magnesium has much higher negative potential as compared to zinc and so is more effective however the dissolution rate of magnesium is higher. So, when we use zinc anode and magnesium anode it is necessary to replace them as and when they get consumed. There are various ways to ground very effectively I am not going to details about that the spiral ground mat is another way of increasing the effectiveness of grounding. When you ground these structures there is going to be a likely problem that these points will act as drainage point for the current to flow from the cathodiculoprotector structures. While we talk about electrical grounding to minimize AC interference we should look at their effect on cathodiculoprotector structures. We know that the cathodiculoprotector structures carry the DC current and these drainage points as so can drain the DC current to minimize the effectiveness of the cathodiculoprotector structures. So, in order to reduce the current drainage the DC current drainage one can use inductive or capacitive coupling which allows only the AC current to flow out of the pipeline and does not allow the DC current to flow out of the pipelines. And these inductive and capacitive couplings are normally set a limit of 10 volts. One can use the polarization cells that allows the AC current and not the DC current. The polarization cells are a typical electrochemical cell that consists of two nickel plates. One end is connected to the pipeline, other end is grounded actually. Now, we know that through this AC current can pass through much easier because this system does not offer any resistance for the flow of current, but DC it offers resistance for the flow of current here. So, the polarization cells are utilized in order to minimize the flow of current from the pipeline on to the earth. When I say flow of current I mean the DC current which we do not want to entrain from the pipeline. To summarize today's lecture we saw that stray current corrosion arises out of the presence of a nearby current source or telluric current. The stray current corrosion can be detected using two techniques one is closed interval potential measurement and other is the line current measurement. The stray current corrosion can be mitigated if you can eliminate the electrolytic current. You can increase the resistance for the flow of stray current, decreasing the resistance for the primary current, provide electrical shielding and you can install the drain points and where possible can have common anode beds that means the two structures can have common cathodic protection systems where this is not possible you can relocate the ground bed. In this lecture we briefly discussed AC interference we saw that AC interference in gentle does not affect corrosion, but however if the AC current exceeds 100 amperes per meter square it can cause corrosion. There are various means you can mitigate the AC interference and so that we can avoid AC corrosion as well.