Sentinel-2 has had a significant impact on land cover slash use monitoring due to its high spatial resolution, high temporal resolution, and availability of red-edge bands. It has been used successfully in various applications including crop, forest, urban area, and water resource monitoring. Furthermore, it is accessible at no cost, making it more affordable for developing countries. Despite these advantages, some challenges remain, such as mismatching with land-set OLI-8 data, a lack of thermal bands, and differences in spatial resolution between the bands. This article was authored by Darius Farai, Matamayo Simwanda, Surajee Seilkin, and others.


At the University of Maryland Medical Center, we're committed to helping our West Baltimore neighbors live greater and healthier lives. Greater means a lot more to us than just medical care. In the last year, through greater education, training, and workforce programs, we provided job opportunities by hiring 18 of our neighbors as patient care technicians. Through programs like YouthWorks and partnerships with local organizations, we mentored 70 high school students and hired 50 additional neighbors as full-time employees, supporting them as they grow their careers and make a positive impact in their neighborhoods and on our city. Greater lives mean healthier options like our mobile food market, which provides fresh produce at a reduced cost as it travels throughout the community and investments like the nearly $10,000 donated by our employees for neighborhood school uniform programs, even purchasing a washer and dryer so students can keep their uniforms fresh and clean. Matthew Henson Elementary School is cooler on hot days thanks to the $4,000 our nurses and doctors donated to provide the school with air conditioners. And through greater local partnerships, we've increased our spending with small business by 50% for things like catering our events. In the past year, we've seen more than 30,000 people at our community health events that offer free health screenings, fitness demonstrations, and information on health and wellness. For more than 30 years, UMMC has continuously reaffirmed and broadened our commitment to and support of West Baltimore. After all, it is our home too. And our collaboration in the community is what being a part of something greater is all about.


So I want to talk a little bit about what drives history and why almost everybody I think gets it ultimately wrong or most people get it wrong, at least most commentators get it wrong when you read about it. You know, the germs, guns, whatever kind of books and other books of that genre. And I'm reading right now, the end of the world is just beginning, the beginning, and of course, Harari has his version. And you read them and first of all, the fascinating books, Guns, Gems and Steel, fascinating books, really interesting. I mean, I love history and they have these amazing stories and amazing theories and a lot of the theories, there's a lot of truth to them and the stuff comes together. And you just learn a lot by reading these kind of books, you learn a lot about the concretes that are going on in the world and have happened in the world and it enriches, it enriches one's knowledge. And this came to mind because I'm reading the end of the world is just the beginning. And granted, I've only read the first few chapters that deal primarily with the past. And let me first say before I criticize the book, you know, my criticism of the approach and my criticism of the book, let me first say that I'm really enjoying the book and I really like it, it's wrong in some fundamental sense and we'll get to that. But it's fascinating, it's really, really interesting and a lot of what he says is true. And a lot of what he says is right and a lot of what he says I hadn't thought of and it's new to me and that's exciting and that's fun when you read a book like that. And it's big in scope, it covers so much. It covers so much of human history and what he's doing in this book is he's setting it up for an analysis of the future, a predictive model, which is great because in 10 years we'll be able to tell him you were right or you were wrong, although he might be right for the wrong reasons, that's also possible. But and I agree with, to a large extent, with his predictions, at least I think I do, and I agree with much of his analysis and the thing that I find most interesting is, and I give him a lot of credit for this, he is absolutely right on how great the world is and has been since World War II and in many respects since the beginning of the Industrial Revolution. He gets that and he gets it in a way that most people don't get. He gets it in a way that the left doesn't get, the left has no clue about, the left is completely clueless about and he gets it in a way that because they're so anti-capitalist, anti-markets and don't have any kind of conception of the state of the world, how poor people were, how horrible life was and what the Industrial Revolution actually achieved and did. But he also gets it better than the right, particularly the right, the kind of conservative right because he says, as of 2019, now he believes 2019 is the peak, life is amazing and to a large extent it attributes why our material life is so good and has been so good over the last, since World War II at least, he attributed it to free trade, he attributed it to globalization. So he is one of the few writers today that I see who are all in on globalization, all in not that he thinks it's gonna survive, he thinks it's gonna collapse completely and gonna go away and gonna drive the world economy into a real rut. But he believes it's a good thing. He believes it's a source of much of our prosperity, much of our success, much of our wealth and quality of life and standard of living, ours and the rest of the world. So he's a huge proponent of globalization and I give him a huge amount of credit for that because it's not easy to be pro-globalization right now, globalization as he explains in the book is found upon, is viewed negatively by almost everybody and left and right. And so good for him, he gets it, he gets it and that is real power. So if you look at now for my more critical part, again, I'm enjoying the book, he reads the book, he's quite a character, he's got a great reading voice, he fills it with emotion. So I actually recommend it, the end of the world is just the beginning, is actually quite enjoyable and interesting, you'll learn something, you'll get a different perspective you'll get for most historians or for me, for that matter. And you will, yeah, and I think his predictions for the future are interesting and quite possibly true, scary, very scary, although if you're in America, less scary, but potentially true. So what is the issue?  And that is that almost all books that try to come up with a large-scale history of the world, story of the world, ignore the one thing that I think ultimately shapes the world. The one thing that in the long run, in a sense, is the determining factor. And that is ideas. For Peter-Zion, the world is shaped by geography and demographics and everything else just happens. He, at least in this book, he doesn't really explain it, it just happens, Industrial Revolution just happens. It's an outcome of a sequence of events that just roll together because of location and because of sudden actions that happened before and it's kind of this causal sequence of events, but there's no individuals in the sequence, there's no ideas in the sequence, there's no culture in the sequence, there's no philosophy in the sequence, there's no political theory in the sequence. There's just things happen and look, they happen, I can explain what they happen through geography and through demographics. And when I read this, yeah, geography matters. And yes, demographics matter, but both are clearly dwarfed, in my view, by the role of ideas, by the role of ideas. So it's fascinating to read somebody who expounds, who's really smart, knows a lot and expounds on history, knows a lot of history, is clearly pro-success, pro-prosperity and yet doesn't see how ideas shaped us all. And of course, ideas are not in a vacuum, ideas are concretely shaped partially by the people who embrace them, partially by the accidents of geography and the accidents of population that partially determine, I don't know, why Aristotle is not picked up, but Plato is, why Aristotle is lost to the West and then we discovered why, is it an accident? For example, Peter Zion talks a lot about Portugal and Spain and the importance and why they are the ones who first go out exploring and why they are the first in the West to kind of go out there and establish navies and it's partial, it's because they live in this peninsula, so they only have to protect one border, things like that, right? And I'm thinking, no, I mean, that's all true, it's true. They have a coast of the Atlantic, they have a coast on the Mediterranean, they're surrounded by water, they also have only one border to protect, all of that is true and all of that probably played their role. But what's also true and maybe much more fundamental is that the Iberian Peninsula is where the works of the Greeks were preserved by the Muslims. It's where in the 14th, 15th, 16th centuries, the best libraries in the world existed. It was where Aristotle's works survived. It was where great Arab and Jewish philosophers lived and it was this fertile soil in which philosophy, primarily Aristotelian philosophy, it was there in the soil, in the libraries. So that when the Christians conquered the peninsula, to their credit, which is very rare for Christians to get credit for me, to their credit, they didn't burn the libraries, they studied them, they took a lot of the books, copied them and sent them to Rome where Thomas Aquinas read them, so that's even the 14th century. So this period of the 14th and 15th century, which are the period where Iberian Peninsula establishes itself, actually Aquinas was 13th centuries, that right, right? A periods in which the Christians are just coming in, they're discovering these libraries, they're discovering these ideas, they're discovering this thought and it is what makes that culture, the dynamic, exciting culture that it becomes and it is what makes them curious about the world and it is what makes it possible for them to sail across the oceans. Now, if those libraries had been in Tbilisi in Georgia, yeah, the world, the history of the world would be very different. The fact that the Arabs went in that direction, established the libraries to the west, established them on a peninsula with a coast of the Atlantic which was easily defensible, all of that it probably is good, all of that probably made it possible. Who knows how history evolves, if they'd gone east then the libraries had gone east. The libraries had bagged that by the way which were even better than the libraries in Cordoba and the great cities of southern Spain, the libraries had bagged that even better but they were all burnt. Where were they all burnt? Before the Mongols even got there, they were burnt and then the Mongols came and basically flattened all the bagged that to where there was left, whatever was left was gone. So the western civilization was reborn in a sense in the Iberian Peninsula and in Italy where these works were read by Aquinas and then influenced the church and would spread through the Italian Peninsula and where focus on this worldliness, happiness in this world and worldly interests was introduced by Aristotle, Aquinas, both to tell you thinking into pre-Renaissance Italy. So really it's those are the places, Italy, Spain and Portugal where you get these ideas. See but that, you have to think, you have to see the world of ideas and this is where, and I don't know what Peter Sihan's views of free will and individual agency are. My guess is he's probably got pretty good views but certainly how are we who's a determinist and who doesn't believe in free will, who views us very much as a mechanistic beings and many of the other writers on history who kind of don't view free will as that as existing or important or determining of the future. They ignore this and again when I recommended The Cave in the Light, this is why I love that book because that is a book that delves into not so much history but the wall of ideas in history through a particular path and a particular lens played over as Aristotle into great book but conventional writers on history don't, many of them don't do that and it's something to be wary of because it's very seductive to hear their stories and to buy into their stories as the cause of factors in history. Guns, germs, and steel is a great example, well-written, interesting, fascinating sequences. They all make sense, kind of, but as Lenny Peacup illustrates in the ominous parallels and in a magnificent talk he gave at Fort Hope Forum years and years ago called The Wall of Philosophy and Psychology in History. Sorry, The Wall of Philosophy and Psychology in History. What shapes history in the end is ideas. When Peter Zion talks about the decline in population, in the demographic decline, the shrinkage of the size of families, the fact that we're having fewer and fewer kids, all of that is true and he can show you mathematically and he can show you from all these countries in the world how it's happening and the speed of which it's happening and so on and you could argue, well, it's just, you get rich and you have fewer kids and you have a lot fewer kids and you have less than replacement and some of that is absolutely true. Wealth matters a huge amount to demographics, to the number of kids we have, but is that the only factor? Does culture make a difference? Does people optimism or pessimism about the future make a difference? If you change the culture, will you change people behavior vis-a-vis children? Well, we know that's true because even wealthy religious people have kids, lots of kids, so religion seems to matter, ideas seem to matter. Israel is a good example, I haven't seen Peter talk about Israel as an example, a county example of the demographics because Israel is a country that I remember not that long ago, a few years ago, really, really, really being worried about the demographics and a lot of people around and because Jewish demographics were collapsing and Arab demographics were holding up in terms of them having a lot of children and then suddenly over just the last few years that shifted and Jewish demographics, Jews are having more kids and Arabs are having a lot less kids, not Arab having a lot less kids is foreseeable because as they get wealthy and westernized, particularly Arabs in Israel and among the Palestinians, they have less kids, which is exactly the pattern. Peter documents and there is consistent with everything we see around the world but the idea that secular Jews are having more kids is strange. It doesn't make any sense. It goes against what you'd expect. Israel's become richer, more successful. It's also become more optimistic. It's also become more energized. It's also become more positive about the future, more confident in its own future. Does that have anything to do with it? I mean, I think so. So culture matters, freedom matters. One of the interesting things is again, Peter talks about the rise of America and its advantages, the natural resources both on the Atlantic and the Pacific coast and a desert in its south, a difficult border in its north but a friendly neighbor in the north, all of that. And everything he says about America is absolutely true. But America would have evolved completely differently and had a completely different destiny, completely different future if America had had a different political system. And maybe political systems somewhat have something to do with declining birth rates, particularly in places like Russia and China. Russia by the way is one of the fastest shrinking populations. All those Putin fans are gonna have to live with a Russia that is weaker and weaker and weaker as we move into the future for all kinds of reasons, among others, population.  And the smartest, the best people leaving. So you can't ignore ideas, political ideas but more importantly, political ideas ultimately are determined by what? They're ultimately determined by metaphysical and epistemological ideas, moral ideas, philosophical ideas. You cannot ignore philosophy. Now it would be fascinating to take what Peter knows Peter Zein knows about geography and demographics and integrate it with a philosophical, cultural, ideological perspective. That would be amazing. And that would be, I think that would be the right approach, the primacy of ideas within the context of geography and demographics. Within the context of germs and guns and other stuff going on. Something wrong with the audio. Francis says, describe America's successful geography and demographics as a bit silly. It is, but it isn't. I mean, America, it was unique. It was unique in that it was a brand new land. It was unique in that it had this ability to expand westward. It was unique in that, that expansion westward also happened to include some of the most fertile land in all of human history. It is unique in the sense that it's the only country other than Canada and Mexico.  I mean, there's a lot of things unique about America that positions it phenomenally worth to be successful, but of course, none of that would have happened. If the audio is weird, it's because of the internet uplink. So there's nothing I can do from here. It's hopefully we'll get better as the internet strengthens. Audio is back, even so. But imagine an America that doesn't have any independence. Imagine America that remains a British colony for another 50 years, maybe 100 years. Does it develop as one country? Does the, what do you call it, the Louisiana protests ever happen? Does America go to water Mexico? There is no America. Is there a war with Mexico to take over the southwest? Is California part of America? Are there five different countries? Are there 10? Are there 20? A reflection of Europe is much of America taken over by Mexico? Is Texas an independent state country? Who knows? Without a set of ideas that shape the union, that shape what Americans want to do with America. Is America, does America have the geography that is so beneficial? Does it have the demographics that is so helpful? Do millions and millions of people emigrate to America if it's an authoritarian dictatorship? Probably not. They emigrate because of the freedom. So the demographics, the huge growth in the American population, and the move west is driven by the fact that America is free. The Industrial Revolution and Britain becoming this amazing bastion of trade Yes, something to do with the fact that it's an island. Yes, something to do with the fact that it sent boats out and traveled around the world and they discovered they could outsource and the trade was a good thing. But there are lots of islands. And the Industrial Revolution happens in England, not because of that primarily, but because something in Britain makes possible the existence of a John Locke and an Isaac Newton, something in England makes it possible for people to start businesses and to profit from them and the attitude changes and the culture changes because of these thinkers and ideas. You cannot take the British and Scottish enlightenment out of England and pretend that everything is the same. It just isn't. These are actually the determining factors. And here again, I encourage you to read the ominous parallels by Leonard Peacock where he shows step by step by step in a fascinating, interesting, beautifully written way the way ideas shape culture, the way ideas shape politics, the way ideas shape ultimately even technological advance. The enlightenment follows the Renaissance which then in the Industrial Revolution follows the enlightenment and that sequence is a sequence of ideas. The manifest in action and reality. And America is a product of the enlightenment. If the Americans had rebelled 100 years earlier, everything would be different. If the Americans would have rebelled 100 years later, everything would be different. Americans rebelled at the exact right time from an ideological, political, philosophical perspective because it was the era where the ideas of liberty, the ideas of freedom, the ideas of rights were at their pinnacle. Pinnacle is not exactly the right word. They were most spread, most around. So when you look at the future, demographics are important. As Peter Zayn says, and we agree on China. But it's funny, he never mentions with regard to China the fact that authoritarian regimes like China don't produce technological advancements, authoritarian regimes like China don't create wealth. For him it's more China's in decline because of demographics. And they are. They're a shrinking population. And it's very difficult for China to generate the kind of economic growth with a shrinking population and much, much more importantly with authoritarian government, authoritarian government. So if you combine our knowledge, our knowledge of political, of philosophical ideas, of political ideas, the politics of liberty versus the politics of oppression, but more importantly, if you combine them with, as Lenin Pekov shows, the wall of epistemology and how epistemology is so crucial to developing a proper moral ideas that are crucial to developing the right political ideas, and understanding of the geopolitics and of resources as Peter does and demographics and geography and all that. Yes, that is an incredibly powerful tool in predicting the future. And I'm gonna say, I think that if you add the demographics, Peter Zayn claims, and I haven't run the math, I guess I believe him, I'm not sure I believe him, maybe he claims China's population is gonna half in the next couple of decades, I think. China is gonna go down to 600 million people. If that is true, that is truly unbelievable, but not only that, the population is gonna age, they're gonna be, have fewer and fewer and fewer productive people in their productive prime, which is true. But if it's that fast, then China's finished. China's finished. If you add to that the fact that innovation is something young people do, working hard is something young people do, entrepreneurship, starting businesses, in other words, wealth creation. If you add to that the authoritarian nature of China and the bad economic policies they're putting together and the ideology of China, which is metaphysically and epistemologically very mystical, the fact that China doesn't have a role model to look at, i.e. no United States that is free, capitalist and prospering, then I agree with Peter completely, China is in deep trouble and I also think that if China is in deep trouble, to a large extent, we need to really think about the extent to which we are, because trade is win-win. We benefit from trade for China. And if we're also going to shut down trade with China, we're in deep trouble. So I like integrating the ideas. For example, I'll give you an example. I was thinking about this. One of the examples that he doesn't really deal with because he looks at a number of children in terms of demographics. But one of the things he doesn't deal with, which I will deal with on a separate show more thoroughly, is the issue of immigration. So for example, the United States is on the verge of having negative population growth. But the United States can solve the problem in a way that I'm not sure China can, although China might do this, we'll see. And that is through immigration. For example, if I was running China right now, I would open Chinese borders. Maybe not on the Western or Muslims, but certainly in the South, Vietnamese, Taiwanese, Cambodians, those are relatively, I think, young populations. Let them come. And if you start seeing a shrinkage in Chinese population, I mean, you will, it's not an if, it's happening, then what you would get is people coming in to come and work in China so that the China doesn't collapse completely. So one way in which you can replenish your demographics is by importing people. Yeah, I wonder if human says North Korea. There's a good idea. What about opening up your border to North Korea and telling the North Koreans, hey, come to China. We'll give you jobs. You know, we'll arrange for you to get jobs. I mean, imagine how wonderful that would be. Both it would be good for China and it'd be amazing for the North Koreans. And of course, people want to go where there are jobs. They also want to go where there's freedom. So some people wouldn't want to go to China. Some people would be hesitant to go to China. But it's one way South Korea and Japan can solve their demographic problem. I mean, Japan is collapsing demographically. I think South Korea is collapsing even faster. Well, again, open up your borders. Maybe some Chinese would like to leave China, certainly Hong Kong. What about the United States? If we're really demographically going to start shrinking, well, we can solve that through immigration. Open up the borders. Bring people in. And you solve the particular problem that Peter is worried about. Now, the problem doesn't go away because the countries from which they're leaving are going to be in trouble. But that's reality. But again, this is determined by ideas. There's a reason why people want to leave Central America and want to come to America. One is free and one is not. The reason why people want to leave Africa and go to Europe, one is free and one is not. One is rich and one is not. But Europe, again, faces horrific demographics which immigration could solve. And here, by the way, again, one of the great benefits of the United Kingdom, one of the great benefits of England, Britain, is that in spite of the fact of being on an island, in spite of the fact that demographically, again, it's a rich island, some people having fewer and fewer kids so there's shrinking population, what keeps England going, what keeps the UK going is immigration. In spite of Brexit to the Brit's credit, immigration has not declined. What's happened is something they did not expect and that is that the ethnic background of the immigrants has shifted so before Brexit, almost all the immigrants to the UK in the years before Brexit were Eastern European or many of them were Eastern European. Not all, many of them. Post-Brexit Eastern European immigration has collapsed but you get increased immigration from India to Pakistan and they are getting quite a bit of immigrants to the Arab world. But this is revitalizing the UK and you might say, yeah, but they're bringing in their third world culture. Well, look at the Conservative government. You guys should list, get a list of the people in the Conservative government. Now, the woman at the top is a, you know, white woman, Liz Truss. But almost everybody else in the cabinet is brown, black in terms of skin color, female, if it's male, the brown, and these are really good people. I mentioned Kemi Badanak who was raised in Nigeria. Born in the UK to Nigerian parents, went back to Nigeria, raised in Nigeria and then came back to UK and then went to high school, I think, in the UK. And today is a prominent politician. But look how many Conservatives, and again, the Conservatives in the UK are much better than the Conservatives in the US, primarily because they're secular. So demographics are non-destiny. Policy driven by philosophy is destiny. And unfortunately, we have brought in philosophy driving today and therefore brought in policy. So destiny is consistent with the demographics.  But it's not primarily going to be because of demographics. It's primarily going to be because of the statism and the fascism and the nationalism and the weight and left-wing statism that is the consequence of the mysticism of subjectivism and ultimately the moral altruism that is driving this culture and that is driving the political agenda of the culture. So in this case, the outcome is consistent but the causal factors are different and this is why I can be more hopeful than Peter can. Because if it's demographics and geography, then it's demographics and geography and it is what it is and it will be what it will be and there's nothing we can do about it. But if it's ideas, if it's philosophy, then we can change our destiny. If it's ideas, if it's philosophy, then we can have an impact. We can, for example, advocate for immigration, which would solve at least locally the problem. We can advocate for, for example, freedom which will increase immigration and increase the productivity and increase the optimism and the efficaciousness of the people around. And I believe that as they become more efficacious, if they're more optimistic, as they're more positive, as they're freer, they will have more kids. We can convince people to think, to use reason, to live, to live the best life that they can live. Again, I think the more people are convinced of that, the more people embrace life, life with the capital L, the more they embrace living, taking their life seriously and the more they're convinced, the more they're certain that their mind is efficacious and they can achieve happiness and they can live a good life, the more optimistic they become, the more productive they become, the more they will demand freedom, the more I think they will even have kids. So if you don't take ideas seriously, then you get caught up in determinism, even if you yourself are not a determinist, even if you believe people have free will, historical determinism captures all. Oh wow, Jacob Rees-Mogg, another real kind of ancient Brit, that's quite a name, Jacob Rees-Mogg, is head of the energy department. Now Jacob Rees-Mogg, last I know of him, was a real free marketer. He was one of the best conservative members vis-a-vis free markets. So look, there's hope for the UK. Now I was hopeful when Johnson was elected and was gravely disappointed, but this looks like an interesting cabinet. So let's give Liz Truss a, let's give it a benefit of the doubt. Let's hope that this is a government that'll live up to the better members within it and actually do something, do something to move the UK towards more freedom.  He's quite good. So you've got a number of good people now in the UK government. All right, let's see, where were we? Yeah, I was wrapping up. So you become a determinist even when you don't are not a determinist individual. You become a cultural, historical determinist because what can change? Ideas can change. Ideas can change. And if ideas change, then culture changes. And if culture changes, then the future changes. Then the path is not set. Thank you for listening or watching the Iran Brook show. If you'd like to support the show, we make it as easy as possible for you to trade with me. You get value from listening. You get value from watching. Show your appreciation. You can do that by going to www.uranbrookshow.com.  Also, if you'd like to see the Iran Book Show grow, please consider sharing our content and of course, subscribe. Press that little bell button right down there on YouTube so that you get an announcement when we go live. And for those of you who are already subscribers and those of you who are already supporters of the show, thank you. I very much appreciate it.


Hello friends, today I'm going to talk you about how you can take care of the health of your kids and their nutrition during the lockdown period. These are time times that we are all at home to prevent the spread of coronavirus, but being at home with kids also bring in a lot of challenges, how to handle them well, but also to take care of their well-being, nutrition and studies. So today I'm going to share certain tips with you which you should, by which you should be able to manage your little ones at home. Since kids are at home, they are spending a lot of time on school, be it a tablet, television or mobile. And on top of that, they have restrictive physical activity due to confinement at home. We can help them by giving them certain tasks each day, which not only keep them occupied, but will also help them learn new things. So if you have a toddler at home, you can spend some time doing little things with them like skipping, hopping or dancing, which they will enjoy, which is not only a good physical activity for them, but also for yourself. Also they can be involved in some kind of creative activity like painting, brushing or reading. Older kids can be asked to clean up their rooms or they can be asked to do regular yogurts. They can help in gardening or cooking. Or even it is a good time to teach them stitching. Reading is one of the best hobbies they can develop at this time. Another important point is that at all times they should follow their regular sleep schedule. As you know that good sleeping habit is a key to good health. Since the weather is getting hotter, we have to ensure that the kids remain well hydrated at home. So in order to do so, again we can give them simple recipes to make for themselves and for the family. That will not only help them develop their interest in eating the food, but also give them a sense of responsibility and achievement. For example, they can make their own lemonade. Lemonade is good in vitamin C, which is also good for their overall immunity. They can also make some fruit salad. They can make their own bowl of cereals with fruits and bigger kids can help their parents in cooking. It is important to eat together as a family and always praise the kids' effort and encourage them whatever they have done during the day. So friends, I just want to remind you all, let's stay at home, stay healthy and maintain good hygiene and stay safe. Thank you.


So we see if it works. Thank you. Okay. I'll set. Okay. So I'll introduce our next speaker. So it's Dr. Manita Denaliuk. And she's going to talk on similarity of anisotropic variable viscosity close. Thank you very much for the introduction. I thank you very much the organizers for allowing me to present this work. So this work is being performed in collaboration with my postdoc now Mikhail Gouding. He's a former PhD student of Professor Norbert Peters who was present at the last edition of the meeting here. And we started to collaborate on this subject and we established an European proposal. And suddenly he passed away one year after that. So two years ago. So I dedicate a part of this presentation and part of this work to the memory of Professor Norbert Peters. The other people who contributed are my students. So this is a part of a larger question that is an appraisal and prediction of variable viscosity flows. Which theory you will see that if things look relatively simple for classical flows, where things are much more complicated for variable viscosity flows. This is the outline of the presentation. So I'll start with the importance of variable viscosity flows with only two short examples. I'll continue with the morphology and phenomenology. Two examples from our previous studies performed in my group. And especially I'll look at the round jet, specially evolving round jet experimentally studied and a temporal mixing layer that is numerically studied. And then I'll go to the core of the subject, which is a self similarity. And I'll mainly address here the question with the tool of the two point statistics. And for the pedagogical reasons I will first present some results in a classical flow. So with the constant viscosity and then I'll go to the variable viscosity flows. And some results in this partially evolving variable viscosity jet. And then I will conclude. The importance of the flow stands in the fact that many practical applications are connected with variable viscosity. And I should say that a lot of attention is being according to variable density flows. But much less importance is according to variable viscosity flows. So to understand which is the effect of variations of the viscosity will concentrate on flows in which the density is matched. And only viscosity gradients are present or viscosity variations are present. So here you have three examples. This is a fluid that comes in an ambient fluid at the same viscosity. So this is a classical jet you see with the classical structures that are developed. The second example is the same fluid that issues in an environment which is 20 times more viscous. So both of them are density matched. So all this structure modification of the structures are due to variations of the viscosity. So you see that the morphology of the flow is very, very different with this mushroom like structures. And the last image is the same fluid that comes in the environment which is 40 times more viscous. And the morphology of the fluid is even more different with kind of pancakes structures and even regions of the center of the jet which are completely unmixed. Another example that I chose for today comes from geophysical applications and these are fountains of magma on the bottom of the ocean and which are the questions that are interesting in this and the shape of the mixing of the edges of that and the distance at which this impinging jet will be able to go. I'll go to some examples that were studied in my group for a few years now. So these are images obtained with a planar laser induced fluorescence and at the left you have a constant viscosity jet in which we mix here nitrogen with nitrogen. And at right you have a propane which issues in an environment which is of nitrogen. So I should state that the nitrogen is 3.5 times more viscous than the propane. So it is the example here is a variable viscosity jet with the ratio of the viscosity of an ambient fluid through the viscosity of the core jet equal to 3.5. So it is not very large. Of course earlier we had ratio of the viscosity that are much more important. However we will see here differences. The initial condition is the same. Here we see the classical Kelvin Helmholtz vortices and at right we have a hint of this large scale that will appear much earlier. But especially we see a mixing of scales that are distributed over a much wider range and the transition towards turbulence is much enhanced and it appears much earlier. The physical interpretation that we offer of that is that because of three kinds of instabilities that are born at the edges that are instabilities that are born because of the viscosity variation stratification instabilities that are associated to the jet. So Kelvin Helmholtz and sometimes depending on the shape of the injector we have instabilities at the wake that is created here. So because of that we have islands of viscous fluid that are enticed into the jet core and this recreates stagnation point that will stop the mean velocity. So the decay of the mean velocity will be much faster. The fluid will stop because it goes into something on an environment which is much more viscous and lateral fluctuations were born. So the transition towards turbulence will be accelerated will appear earlier and the mixing will increase. These are images also obtained in our specially evolving jet with planar laser induced fluorescence. At the left we have the mean scalar field in a constant viscosity flow. So it's nitrogen with nitrogen and in a variable viscosity flow propane with nitrogen. And at right we have the RMS root mean square so typical fluctuations of the scalar field constant viscosity and variable viscosity. So what we see for both of them at a larger potential core in a constant viscosity field so the flow will go much further and here it is a potential core that is much more reduced. And also the maximum of the fluctuations that appear here that appear much earlier very early in the very near field then here in the constant viscosity that will appear later. So once again we have turbulence that will be born much earlier. Another example is a temporarily mixing layer that is studied using DNS. So I chose not to give a lot of details here but you have two streams one rapid and one slower with a variable viscosity. So and the rapid stream is less viscous than that which is slower. So what we see that evolution through the time of different quantities here is the evolution of the mixing layer thickness. Defined like that when the ratio of the viscosity increases so between the two streams this mixing layer thickness evolves much rapidly. So the mixing layer opens much more and mixing is enhanced and also all fluctuations are born earlier. This is the profile of the mean velocity in our temporal evolving jets. So this is the rapid stream at the low viscosity stream. This is the slow stream at a higher viscosity stream. And we see that when the ratio of the viscosity here results go up to a ratio of viscosity of 9 but we had the simulations at a higher ratio of the viscosity. So we see that of course the rapid stream is slowed down because of the world viscous world fluid world that is situated in this region. Whereas the slow one is of course accelerated and much more differences we see when we represent the derivative of the mean velocity that is represented here. We looked in order to quantify which are the terms responsible of that. We started from an aviastox equation and we derived the transport equation for the mean velocity field in here in a temporal mixing layer. And of course these are the classical terms and all these four terms are specific to the variable viscosity because we have viscosity derivatives, viscosity fluctuations, viscosity fluctuations and derivatives of that etc. The most important terms that appear of course is specific to the variable viscosity term is this in red. You see that it is the most important and this is down to the fact that the rapid stream is at a lower viscosity so we are in a counter gradient configuration. So this will contribute to the fact that the absolute value of the mean velocity will evolve much faster in time so the evolution will be enhanced. If we go now we look also for the temporal mixing layer to the turbulent kinetic energy and here these are the squares of the three velocity components and again we represent that as a function of time. This curve corresponds to the ratio of viscosity of one and it increases up to I have here up to nine and we see that the turbulent kinetic energy increases so this validates and corresponds perfectly to what we have seen in the jet earlier that turbulence is enhanced and it appears much earlier. In order to correlate that to the transport the first principles and the transport equation that we derived that from the Navier-Stokes equation and we derived the transport equation for the total kinetic energy. We see classical terms that appear. This is the production term that's still the most important as a magnitude here but in which the derivative of the mean velocity is very enhanced because of the reason I have presented earlier. The profile of the mean velocity is modified because of the viscose wall that is situated nearby. And we have a supplementary terms of course the second and the third line that correspond and are specific to the variable viscosity terms. Here we have a production term is positive here that corresponds to the fact that blobs of fluids which are viscose that will correspond to a lower kinetic energy. The production of that will be a result of the viscosity gradients and this is an extra dissipation so it's a negative term here that will be due also to the viscosity gradients. So we have shown once again that turbulence fluctuations are born faster, mixing is increased and the next question we are interested in in order to solve all these equations and to have a prediction of how mixing is evolving is do we have self-similarity? As you know if I come back to a round jet it is one of the flows that are self-similar. The Reynolds number whatever is calculated are lambda or etcetera stays constant along the axis of the jet. Is that the case again in a variable viscosity jet or variable viscosity flows in a general and we'll do that by looking at the two point statistics. And for pedagogical reasons I'll just introduce some things for a constant viscosity and of course I'll go immediately to the variable viscosity. This is the image of the cascade as introduced by Richard so on etcetera and Kolmogorov said that if the Reynolds number is sufficiently high then all these small scales should be locally isotropic and universal. And one way to understand what happens at the scale is to consider increments of differences of here u but it can be any other turbulent flow a turbulent field between two points of the space separated by a distance r so this is an increment or a scale. And we can calculate moments of second order moments, third order moments etcetera. The second order moment correspond to the energy at the scale r and all smaller scales and of course they are correlated they correspond to the spectra. The third order moment correspond to the energy flux at the scale r. And now Kolmogorov said enough he said several things in K41 that for K in 1941 says the theory known as K41 that for sufficiently high Reynolds numbers he introduced the similarity hypothesis and this is the first similarity hypothesis that said that at the end order moment of velocity increments when they are appropriately normalized that should be universal functions of a scale r appropriately normalized with respect to the scale that is known as Kolmogorov scale and defined by that by this expression. Based he derived that based on a phenomenological basis and there is also the second similarity hypothesis that I will not take care in this presentation that deals with the scales much larger or that's situated in the inertial range if the Reynolds number allows that to exist. So I concentrate the following of my presentation on two issues related to the first similarity hypothesis which are the functions f can that be invariant in when different parameters of the flow varies space time Reynolds etcetera. So when I change one parameter of the flow if we normalize appropriately the functions do they stay similar so do we have self similarity. I recall that that is very important because when we go back to the equations having solutions self similar solution and self similar transport equation it is much easier to be tackled analytically and or numerically etcetera. And which is the expression of the similarity scale because Kolmogorov provided the expression but that was based on a phenomenological basis. Another thing that Kolmogorov did in 41 in another paper is he derived his equation so from Nagia stock so from the first principles this is known as the fourth fifth low so the third order moment are related to the second order moment and this is the energy transferred at any scale. If the Reynolds number is sufficiently high and if we placed ourselves in the inertial range then this reduces to the third order moment equal to four fifth mean energy dissipation rate time the scale or what we have seen for instance with this result published in 2006 is that if we consider the maximum of these functions and we normalize appropriately so by epsilon r so we compare that with fourth fifth. We need Reynolds number as high as 1000s here for fourth turbulence and as high as 10000s here for decaying turbulence so very high Reynolds numbers in order to have this constant for fifth to be to be to be valid. So for most of the flows these are experimental points that we had a bad time for most of the flows in laboratory or real flows etcetera the atmospheric boundary layer should be somewhere somewhere here are affected by the finite Reynolds number effects. And in order to solve this we went back to the first principles and we really arrived with Kolmogorov equation or for the transport for the scholar etcetera etcetera but by consider what we call the large scale terms or forcing terms here. That if we only represent these terms as a function of the scale r these terms are not important at small scales but they are more and more important at intermediate scales and larger scales. So large scales these are these forcing term that is associated actually to the shear or to decay or if we are look at that for the scholar for the mean temperature gradient etcetera. So it's everything that is flow specific that will appear and will be represented in this forcing term. So now we have the good tools part of K41 was really writes and we have the good tools in order to apply that to real flows and the finite Reynolds number flows. And if I advance now to go to the similarity the first similarity hypothesis that concerns scales in the dissipative range and inertia range if the Reynolds number allows for that to exist. So by working on this transport equation but completed by forcing at a large scale we may apply the self similarity analysis. The self similarity say once again if we appropriately normalize all that that these terms should stay similar so should be the same when completely normalized. So one form of that is the equilibrium similarity as proposed by George 92 for spectra and by our group later on for structure functions etcetera. And mathematically that said that for instance for the second order structure functions that should be written as a shape function that depends on the scale normalized with respect to a characteristic length scale. And a coefficient in front of that that will depend on any parameter P that I put it in in red that can be the space the time but it can be also the energy injected in the flow of for instance the Reynolds number. So when the Reynolds number increases that this term may stay self similar if we normalize with respect to adequate scales. Same thing for the third order moments and etcetera all terms that will appear in the equations we are interested in. Now this is a self similarity that comes in to play self preservation as was introduced by Townsend in 56. And he understood by that a particular case of self similarity when this parameter is only the space for instance X for specially evolving jet or it can be the time. So it's when the when the flow stays self preserving that following an evolution in space or time. Now I will substitute this functional forms in the scale by scale transport so this transport equations here we choose as a normalization basis the dissipative term here. So we multiply by whatever will appear here the scale L divided by the square of the characteristic velocity and divided by the viscosity so this will become a constant. And we impose that each term this is the equilibrium similarity that each terms should stay constant because one of the terms is constant. And all the other coefficient should should stay constant during this transformation. Convangore was speaking about a fine transformation of the flow. So independently on the language we use the state that when we apply modification of the flow that all these things should stay self similar. So we should have real real coefficient in front of that. So this third order time that's that represents the energy transfer. It will lead to the Reynolds number built with the characteristic length scale and with the characteristic velocity scale and with the of course with the viscosity. Now I'm in the case with the constant viscosity that should be constant during the transformation. And this term will lead to a relationship between epsilon that is here. It is the energy transfer at the level of the smallest scales divided by the viscosity and multiplied by the square of the scale and divided again by the square of the velocity that should be constant. This is a system these two terms a systems of two equations with two unknowns the velocity and the scale. If we solve that then the solution is the Kolmogorov scale. So this comes from the first principles and from the transport equation here Navier's talks. Moreover if we impose that the characteristic velocity should be the variance for instance. So that is characteristic of the larger scale. So characteristic length scales can be identified with the Taylor micro scale. And you know the definition so it can also be a solution. But the natural solution that emerges is the Kolmogorov solution. So if we speak about a complete self-similarity or complete self-preservation that signifies that all scales will stay self-similar or self-preserving during the transformation that all these scales are proportional. So eta Kolmogorov scale and lambda the Taylor micro scale will be proportional. All the other terms the forcing term will lead to other constraints that will lead us to the conclusion on how the characteristic scale evolves through the scales. And of course this was validated by many studies but maybe the most representative is that of the spectra normalized with respect to the Kolmogorov variables that do collapse over the dissipative range and scales or wave numbers here smaller and smaller. In conformity with the first similarity hypothesis. Now this was for constant viscosity flows but our issues is for variable viscosity flows and is self-similarity valid or not. So we derived the details appear in all these papers and two of these papers. We derived the transport equation for the total kinetic energy. This is a summation over i so this is the total kinetic energy at a scale r. So this is the time derivative of the total derivative. This is the diffusive term. This is the energy transfer to the scale and note that this form of the equation takes into account anisotropy because this is a divergence term and here we'll have the Laplacian term here. We are not yet developed as a function as in a spherical coordinates for instance which is the case when anisotropy is valid. So this is a very general form. We have divergence and Laplacian and etc. And anisotropic flows can be tackled with these tools. So this is a production term etc. So all these blue terms are classical terms but in which we have considered viscosity variations. So for instance here note that for the diffusive term we have the viscosity that is coupled with the total kinetic energy at the scale, the bed scale. And all these red terms are specific to the variable viscosity flows because we have gradients of the viscosity and gradients for instance of the viscosity increments. So as soon as our flow is the constant viscosity all these terms go to zero and all these terms reduce finally to the form that we had for classical flows. One of the aims of us is to close this term because we have many, this is the classical term that is unclosed but this is another term that is unclosed because we have the correlation between the viscosity and the total kinetic energy. And the higher order terms will have other terms that will be, will have to be closed. So if we succeed in closing all that then we will be able to predict the kinetic energy so how mixing is performed at each stage of the flow. Now if I simplify a little bit the things and I consider the central region of a round jet in which local homogeneity I'm still in an anisotropic context is considered. So I neglect some of the terms so this is a little simplified form of the equation. We have here a transport, a turbulent diffusion, a production, production or destruction by viscosity gradients and the dissipation. Note that the dissipation is defined by mean values of the viscosity times the square of the velocity gradients. So for that we apply our equilibrium similarity or self similarity analysis and we impose that all these functions should be written as a product between shape functions. Of psi which is the scale normalized with respect to a characteristic length scale and coefficients in front of that and we reapply the exercise. Then we have supplementary difficulties because we have this new term that is the total kinetic energy coupled with the viscosity of the two points. And this can be written as a reference viscosity at that position times a function that we can consider. And the new term that is very specific to our variable viscosity flow is that the decay over x of the viscosity. Because we go in an environment which is more and more viscous but it can be less and less viscous but at variable viscosity. And of course the decay over x of the total kinetic energy because in our jet that the kinetic energy decays. So that will be written as the derivative over x of the reference viscosity times the derivative of the kinetic energy and of the function times of the shape function here. And of course we do the same thing for the viscosity. So a little bit of attention to this mixed term viscosity total kinetic energy that can be decomposed in a mean value of a reference viscosity. And in the following at least for now we only consider this mean value but we can also have a contributions from the fluctuating value of the reference viscosity. So if we replace all that and we do the same kind of exercises previously for the constant viscosity flow. Terms are the same except the viscosity was replaced by the reference viscosity because the viscosity varies. And we have this new term which is specific to our flow because we have the decay of the reference viscosity and the x derivative of the kinetic energy. So it can be shown that again if we look specifically at the very small scales the Kolmogorov scale naturally occurs. But the Kolmogorov scale that will be defined now with the variable viscosity epsilon defined in a variable viscosity flow. And the viscosity that is a reference viscosity. So for now I have only considered that that position in the flow the mean value of the viscosity. It can be shown of course that if I look at larger scales at the Taylor micro scale can be also derived as a characteristic scale. In which again I should take into account the reference viscosity in our flow and variable viscosity dissipation as a reference that was considered. If the flow is completely self-preserving then all scales are proportional of course but for now we do not have a clear evidence for that. But we have a better insight on these slides and if we suppose power loss now for the mean velocity for the characteristic velocity. Typical fluctuation of the velocity and for the reference viscosity. And we consider that the mean velocity will decay at x to the minus nu. The typical velocity will decay with x to the minus nu. So this is a capital U and the reference viscosity will vary at x to n nu. Let's say n nu positive if we go in a more viscous environment. So if we replace all that in our systems of equations and again with a particular attention to this term here. Which depends on the derivative of the viscosity. Then and we combine all these we obtain different constraints. And if we work on them that this is a very important result that we can cover different scenario. The first of one is with if n nu is equal to zero. So this corresponds to the fact that the viscosity does not vary. We are in the constant viscosity case that of course and U equal to one. So the mean velocity will decay as x to the minus one which is a classical result in a constant viscosity jet. But if n nu different from zero. So if we have any variations non-negligible variation of the reference viscosity which was for us the mean value of the viscosity. Then if this coefficient this exponent is different from zero then and you cannot be equal to zero. So we do not have a conservation of the jet momentum. So all the classical things that are known for the jet are modified. Moreover and I did not I do not develop here but if we work also apply the same analysis to the transport equation of the scalar. So the mixing fraction that will produce the mixing in our in our jet. And if we come back to our result in the Navier stocks that we can show that the Reynolds number calculated the characteristic velocity characteristic scale. And the reference viscosity cannot be constant during the decay. So as soon as we have the viscosity variations then the product between the velocity and the characteristic scale can be kept constant. And if the viscosity is constant which is the case of the constant viscosity jet then the Reynolds number will be constant will be kept constant. But if the viscosity varies this Reynolds number cannot be kept constant. So we conclude at this stage that self similarity or self preservation cannot be achieved in a variable viscosity jet even if the viscosity increases or decreases. Now because we pointed out this pessimistic conclusion so the variable viscosity jet are not easy to be tackled the difficulties are much more important that in the classical jets. So life was not meant to be easy as one Australian prime minister used to say. Now we try to test a little bit and to and to look at the different functions. So this is our correlation between the viscosity and the second order moment here. And if we test that at the different diameters downstream these are results from a PIV performed in our specially evolving jet. But we see that self similarity at least for these things holds on the axis of the jet in which the mixing is relatively well performed. But if we go on the shear layer and the borders of the jet then these functions are not similar they do not have the same shape. Now an important point was the closure of this term because remember I used the reference viscosity that came from how we wrote this term here. And I decomposed in a mean value times the correlation between the fluctuating viscosity and the kinetic energy. And we tried to see if the mean viscosity is sufficient to close all that and so we looked at the shape of this mixed structure function and the second order structure functions of the shapes are different at least at large scales here both in the central region of the jet or the axis of the jet and also in the shear layer where the difference is more important. So the mean viscosity is not sufficient to reliably close this term. So we went more we looked at fluctuations of the viscosity and here we consider the RMS of the viscosity times the second order structure functions as a closure. And this closure is much more so the ratio of these two functions is nearly constant over a range of scales that is more important. So this closure which is not perfect but is much better than the mean value of the viscosity is supported by experimental data and the reference viscosity is even more complex than the mean viscosity. So the analysis can be performed again if we went back to our analysis but now the reference viscosity will be this fluctuation of RMS of the viscosity. So this signifies even more that self similarity is not likely to occur in variable viscosity flows with large scale viscosity gradients because it is required that the mean value of the viscosity should be locally constant over the scales that are relevant for the flow of that position but also that the RMS so next order fluctuations of the viscosity should be locally constant that for the similarity to be valid over that region of the space. So as a conclusion of that is that self similarity is much harder to be achieved in variable viscosity flows. Now if I look at just a rapid look at higher order moments transport. So this is the transport equation for the fourth order moments in which we have this we have the now the divergence of the term but we have the fourth order moments here production term that will be specific of the flow. Again the decay of the viscosity times the decay of the fourth order moments here that can be decomposed etc. But the dissipation of the mean energy dissipation rate does not appear as such. We have the correlation between the second order structure functions and the dissipation. So things are much more complicated. We need a closure here for this term and for this case I will have a talk on Wednesday afternoon and I will develop that for a passive scalar and a little bit for an active scalar. K41 so even the Kolmogorov scale is not does not have the classical expression because it cannot be written as a function of epsilon. It can it should be written as a function of epsilon square here because this term will be developed at the square of epsilon divided by the adequate scales. So things are even much more complex in in variable viscosity. The last result that we performed and this is a work in progress or everything is working progress but we perform a DNS for homogeneous isotropic turbulence with variable viscosity. So now we went we want to go to a little bit simpler flows. So the flow is homogeneous isotropic turbulence and we introduce the viscosity variations of the scales that are much smaller and we look at the correlation between the dissipation velocity gradients and the viscosity. And when I skip the details of the simulations I'll just these are images. These are low viscosity in blue regions and high viscosity here and during the transition the mixture the mixture field will be wrinkled and it will become convoluted by vorticity. So we have a mixing during the time in flow which is homogeneous isotropic turbulence. And in this flow I recall that homogeneous as decaying homogeneous isotropic turbulence is not self-preserving because the Reynolds number decays simply. So very small scales that can be locally et cetera but the Reynolds number decays. So this is basically a flow that is not self-preserving and we show that of course variable viscosity will not be self-preserving. So this when we have results of all that I will stop here. These are the structure functions we have obtained during the decay. Well we show that in some way Taylor's postulate is confirmed because the ratio of the viscosity stays that does not influence on the shape of the functions when we appropriately normalize all that. But during the decay the shape of that evolves so we do not have a self similarity we do not have self-preservation in a variable viscosity flow. So as a conclusion I have shown that in flows with viscosity gradients or viscosity gradients we go faster towards turbulence we mix faster. So things look to be simpler and is better for applications like combustion and the questions from combustion people actually were the origin of this flow of this study. But on the other way for things that are more fundamental et cetera classical theories are little useful. So we have to redefine and to go back to the first principles and to redefine epsilon to redefine the production correlation between the viscosity et cetera and especially if initial flow of the constant viscosity field is self-preserving as is the case for a round jet especially volume round jet then the variable viscosity flow cannot be self-preserving or not completely self-preserving. It can be over distances over the space but not over large distances because air lambda will evolve will go in some environment which is more and more viscous. And other flows in which the basic flow is not self-preserving but invariable viscosity will not be self-preserving again. Thank you very much.


and welcome back. So yes today is going to be more around when's quarter four's going to start? I mean proper quarter four. I mean we haven't seen the general increase that we would normally see or become accustomed to seeing at this time of year. Before we go any further just to answer my prediction from yesterday, if you saw my control traffic content yesterday, I made a prediction just to show how I am pretty close on what I expect when I see traffic coming in and how I can calculate it very well and I predicted that for yesterday's traffic on promoted would be around the 163k ish for promoted and I would receive between one or two sales, one or two low sale price sales. So the results of that checking in today and I'll pop it up on the screen for us to see was 145.9k promoted impression so it was actually lower than I thought it was going to be out of the blue but I think even though it was out of the blue I did actually tweak my promoted impression percentage rate yesterday. I reduced it by 1% which seems to have had a bit of a bigger impact than I thought it was going to have. So yeah I think that's probably what I can assign that to otherwise I would have sat around 163k but there was no spike. I hadn't ended and re-listed a lot of my listings. I literally just let it roll but obviously I did new stock yesterday and the day before and the day before that so it should in effect of actually have increased not decreased but roundabout where I expected I'm 146k rounding it off a little lower than I was expecting even with a bit of a fluctuation I'm hoping to bring that back a bit today but we shall see because I've made a bigger drastic change on the promoted impressions today. Pretty much on the back of testing out Darth Rifter's content yesterday around the percentage marks that they run at sorry that he runs at and what he's suggesting you should really be looking at as opposed to the suggested at rate. I'll give it a try. I think it was just to see for 24 hours to see what the impression rates are affected by and see what that comes out at. It's interesting to do small tests. I don't want to do too large on my main store because obviously that will have too much of an impact on the sales that I am getting but I did predict my sales correctly. Now for going forward I'm going to predict again today that sales today will finish on between three and four today. I'm thinking more four than three. I think it will also bring in a revenue of an increase from yesterday of about a 50% increase on yesterday's revenue between 30 and 50%. So we'll see what comes up tomorrow. I don't like giving out pound of values. I don't think that's really relevant to the overall picture at this stage. This is more about statistics as opposed to financial status settings. So yeah, so that was a catch up from yesterday's content which I'll leave a link above if you want to watch that one. Again the quarter four it's not happening the way it should. I don't know if that's predominantly people are holding off still waiting for the November paychecks to get their December gifts in for the festive time. I'll say Christmas I'm not to PC that way. It just is what it is. It is Christmas time. Now with this in place, what can I say? It's not going the way it should. I mean I've been looking at my figures and this month on previous month I'm up 27.2% on sales but last month on the previous month I was up 96%. So it's not growing as fast as it should considering we should be pushing into the quarter, middle of quarter four. It's possible they could be all holding out for Black Friday sales. It's possible I guess but this quarter I'm actually down 9% on previous quarter which is just crazy. It's just crazy. We should be increasing not going down. It's just not making sense to me at all at the moment. Year on year I'm down 17.8% but my average sales price actually increased by 22.7% so at least I'm getting the ASP up but the buyers are down 33% so I'm down a third of the amount of sales but I'm up 22.7% on average sales price but overall I'm down 17.8% year on year. Now this could just be a knock-on effect from the massive amount of changes that eBay be making on the platform and we've all been readjusting, testing, trying, re-correcting and improving things but we've got to ask ourselves what do we really expect from quarter four? I think in all honesty that the massive sales from quarter four is not going to happen. I think we just need to accept this and readjust our expectations and our goals according. We need to think about the quarter one for 2024 and definitely think that's got to be high on our assumptions of what we need to be planning for but at the same time obviously quarter four of 2023 isn't over so there are still potential opportunities available to us and it's difficult to decide what direction to go in. eBay don't give us a detailed schematic of what directions are going, what we need to be precisely looking at for our individual accounts and our listings and it does give us the quality report which does give us a good indication as to where we sit amongst the competition. It gives us a good indication as to where we could improve certain aspects of listings as a group or as a whole but it doesn't specifically say that you need to get say your price tweaked in a certain direction or if you increase your promoted impressions in a certain way or in a certain pattern it will help you in a certain direction. It does in some forms with regards to dynamic ad rate and automated and you know these type of things but they're eBay governed, they're not governed by ourselves if we choose those options. I mean for example I mean the dynamic ad rate suggested ad rate you know I mean I've mentioned it before it will say suggested ad rate for a particular category would be say 18% but then when you go and look at your quality report it says the top 10% of other sellers in your category are only promoting at say 8% so there's a clear money grab by eBay there that is perpetuated to all sellers to say you should be doing this you should be doing it at that percentage when we can see that there are people that are successfully selling to whatever degree at a much lower rate I mean when you look at that quality report for example with that one you look at the bottom 10% they're also not using promoted impressions to the 18% mark they're also using it around the 8 to 9% mark so where it says suggested I think suggested is a bad move but at the same time the question then you ask yourself is but if I don't do it at the 18% will the algorithm then hold it back from me I don't know it's a simple answer and we can try it and we can see what happens but can we afford to do that in the current marketplace with the with the stranglehold on sales for whatever reasons can we really afford that loss in profit margin from potential sales it kind of falls to where's your stamina hold out to you know I will try my best to test the water with a few of these different things in different areas more probably on my second account which obviously as I'm running the tweaks that were mentioned from Jeff's video the other day that like I also covered in a different viewpoint on some of those then obviously as I've gone through those and got some data back from that then I can report that out and then I can move on to the next thing so it's going to be a time time restraints as to how fast I can get my personal findings out but again they're all individual because everybody's account is affected in a different way it's it's a road we have to keep going down on a daily basis for sure and it is frustrating and we've just got a we just got to keep plugging in there and yes something sometimes will work sometimes some things won't work and sometimes they'll work at a different time in a different way because they've been impacted by other things and I never think we'll get a hundred percent clear route we're always going to be testing and trying and flipping between different ideas as to what those ideas may be we shall see we shall see but I'm happy to share what I get how I get what you take from it is entirely up to yourself but if you have any more ideas feed them back to me please answer the community in the comments and obviously we can all try different things some things that we think will be great for us will try and it doesn't work but somebody else may see anything I'll get that ago and it works great for them and that's brilliant whatever it takes for everyone to experiment and try and always look to strive further ahead on your account and improve it they all have a positive outcome even if they don't work that's still a positive outcome because you've now figured out that that doesn't work for you so you can leave that aside and not address it again until maybe you find that you've exhausted all options again in the future and it may well be worth revisiting and trying again who knows the algorithms always changing the AI is always learning the accounts are always moving in the strength and the positioning and obviously with the searching from the buyers themselves their search histories will change so as certain categories certain products gain relevance on the platform your items may come back into favor so these are all things obviously we all learn on a day to day basis and we all juggle with on a day to day basis and our sellers so let's work together you know let's get to keep it forwards but as far as quarter four I think we have to accept that it's gonna be an uphill battle it's definitely gonna be an uphill battle there's nothing flowing forwards there's nothing increasing exponentially at the moment and it's gonna be it's gonna be a challenge and I think it can be a positive challenge we just need to make sure that we don't let it overcome us and eat us from the inside out we just need to keep striving forwards but as far as moving upwards and ending quarter four on a high note let's keep our fingers crossed and let's just keep going and in the community we can help each other and let's just keep you real because that's what it's all about isn't it you know keeping it real keeping the facts there and let people take from it what they will it's difficult time I'm struggling I know you're struggling but to to give in now would be crazy I think this is where things start improving maybe not instantaneously on a quarter four level for sales but certainly for an understanding of the platform and the changes and how we're going to need to readjust our strategies moving forwards I don't think the list it and wait for to sell approach is is is sustainable anymore but depends on the product you're selling of course but I just don't think it is personally I think there's going to be a lot more work involved and yes if we can game the system by doing things that are a little bit outside the box on a listing or to an account then I think all credit to it let's do it because if it makes more sales at the end of the day it can only be a benefit and we can always change it later if we need to so that's me for now I will get the viewers comments out possibly by tomorrow now I was hoping for today but I think it's more likely to be tomorrow at the rate things are going I need to get some stock on and obviously time restraints all around as we are all experiencing can be a bit difficult so keep you real and see you in the next video take care bye bye


What's going on guys? It's your boy DPGA here today with another destiny video and today we have top five warlock Supers of the week and if you guys do enjoy the video and you are a warlock and you think warlock is that master race Do smash that like button as it really does help out submit any baddest clip you've got to the email I just linked in the top of the video description and I'll catch you guys on that next one Guardian, our guardian revive your teammates for a comeback. All enemies have been eliminated Munition pesada disponible 2x1. Sí, tres derribados, mira como caen Zone B lost three down. This is amazing Zone a neutralized Zone a secure