WEBVTT 1 00:00:05.850 --> 00:00:15.059 Mark Kushner: Good afternoon and welcome to today's special nitze seminar is being part of the michie graduate symposium it my pleasure to. 2 00:00:15.570 --> 00:00:27.000 Mark Kushner: introduce a devotee corralling who is associate professor in the department of nuclear plaster and radiological engineering at the University of Illinois at urbana champaign and. 3 00:00:28.140 --> 00:00:36.060 Mark Kushner: appointed at the national Center for supercomputing applications, he is also the bigger well that faculty scholars. 4 00:00:36.720 --> 00:00:52.260 Mark Kushner: You received a PhD from the University of iowa and 2011 it was also a postdoctoral research their research or their ID then move to the University of Illinois, which is a lot more picture risk than I do. 5 00:00:53.520 --> 00:01:04.560 Mark Kushner: where he was first a postdoctoral researcher and a shame assistant professor and now an associate Professor he needs a laboratory for communication classes it's. 6 00:01:05.190 --> 00:01:18.930 Mark Kushner: A very broad portfolio of research focused on computational modeling and password surely interactions plasma chemistry of luxury for plasmas and passively interactions that will talk about today. 7 00:01:19.440 --> 00:01:43.530 Mark Kushner: and on these topics w has published more than 100 papers, the applications of these fundamental studies from fusion to nuclear applications and water cleaner he's developed several new modeling approaches, including both fluid and kinetic models and it will here today, open source software. 8 00:01:45.510 --> 00:01:55.260 Mark Kushner: Currently, is also coordinate or the nuclear firewall chemistry activities within the university research Elias the Defense stress reduction agency. 9 00:01:56.190 --> 00:02:09.900 Mark Kushner: The title of the talk today is a plasma water interface modern challenges and new software tools, but before that we have two very important presentations The first is the team. 10 00:02:11.430 --> 00:02:18.480 Mark Kushner: As we like to say there are fewer recipient to the misty mug and there aren't Nobel Prize winners so here's. 11 00:02:28.740 --> 00:02:48.630 Mark Kushner: And the second is a physical currently is this year as an MC early career lecturer, which is our early career awards to rising stars and risen stars in the field of plasmas and we have noticed their excellence by this special. 12 00:02:49.680 --> 00:02:54.210 Mark Kushner: invitation and recognition for that we have a little fun and Kim. 13 00:02:55.260 --> 00:02:55.470 Mark Kushner: and 14 00:03:01.290 --> 00:03:03.300 Mark Kushner: I will hand it over to you, thank you. 15 00:03:05.310 --> 00:03:16.050 Mark Kushner: All right, well, can you hear my voice is it coming through perfect I mean it's a pleasure and wake up to the seminar if you're attending online or if you're attending person. 16 00:03:16.440 --> 00:03:26.100 Mark Kushner: So much better feeling being present in inside the same room with real people that I can talk to, especially after two years of pandemics so. 17 00:03:27.660 --> 00:03:38.220 Mark Kushner: First, let me go through the people in my group, I see that there is a banner on zoom secondaries to click here. 18 00:03:45.240 --> 00:03:49.170 Mark Kushner: When there is a small window here got it okay. 19 00:03:56.790 --> 00:03:57.180 Okay. 20 00:03:59.460 --> 00:04:04.050 Mark Kushner: This is full screen no windows perfect okay sorry for the technical communions alright so. 21 00:04:05.160 --> 00:04:16.050 Mark Kushner: I am the director of the laboratory of computational physics at the University of Illinois right now the snapshot of my group is, including a graduate students and three PhD candidates. 22 00:04:16.560 --> 00:04:25.230 Mark Kushner: And the words that will be presenting today will be mainly the walk of shame kenai la who will be graduating soon. 23 00:04:26.640 --> 00:04:30.030 Mark Kushner: And you can recognize that is graduating soon from this mile because it's. 24 00:04:31.290 --> 00:04:33.510 Mark Kushner: Very it's a gradient of happy faces of the last one. 25 00:04:36.330 --> 00:04:43.680 Mark Kushner: Okay, but this is not work that we've done alone, there is also an experimenter component i'm not an experimental least them a computational Easter. 26 00:04:44.280 --> 00:04:59.490 Mark Kushner: And there is a an experimental portion of the story that was done by a professor of sundance mohan synchronous trooper and Dr michiko urinary and we also have an undergrad with the Elizabeth Perez, who has worked with shane for the duration of this project. 27 00:05:00.750 --> 00:05:08.520 Mark Kushner: So the main question is a simple one, how do we model, a plasma screen is interacting with liquid water. 28 00:05:09.300 --> 00:05:17.910 Mark Kushner: try to understand this problem here here here you have a nice picture of a plasma taking from a word from Alex means they. 29 00:05:18.630 --> 00:05:25.500 Mark Kushner: publish previously and also are we actually able to construct a modal dairies predictable. 30 00:05:26.160 --> 00:05:37.650 Mark Kushner: Meaning can we do an actual validation meaning comparing the modal predictions, with an experimental measurements are to the point that they agree it's not a trivial question, especially for a plasma system. 31 00:05:38.250 --> 00:05:56.760 Mark Kushner: If you are familiar with plasma say you typically oh yeah if it's within the same order of magnitude the model is already fine, but can we do better than that, so I have two goals for today, the first one is showing you some recent open source software that we develop better. 32 00:05:57.960 --> 00:06:04.290 Mark Kushner: it's based on the moves finite element framework or you might have already used for some other projects so. 33 00:06:05.760 --> 00:06:12.030 Mark Kushner: Pretty generic combined software environment where you can go and build your up your application. 34 00:06:12.630 --> 00:06:20.820 Mark Kushner: And it's pretty pretty Nice because of the applications that you believe in that environment can be couple the two other applications, and so you can gradually construct. 35 00:06:21.330 --> 00:06:32.280 Mark Kushner: Models of increasing complexity and Moody physics features and we'll be talking about shoe applications that you might find interesting crane instructors. 36 00:06:33.570 --> 00:06:40.620 Mark Kushner: crane was developed by my group it's essentially a chemical kinetic software, and these are extremely important in plasma chemistry problems. 37 00:06:41.070 --> 00:06:53.910 Mark Kushner: Because the chemical kinetic said I don't want to say it's everything but it's a very important component so very important piece, you want to know which radicals your plasma is generated and that does, who is familiar with documents here. 38 00:06:54.960 --> 00:07:07.920 Mark Kushner: Okay, so sorry i've seen that one and okay so what's the main feature of the units after the park when it's an electric for it's an electric bird so the flies and it's a library. 39 00:07:08.460 --> 00:07:21.300 Mark Kushner: And so there is a there is a story between all the moves applications among the most applications, you want to give names that are like any more names to the applications. 40 00:07:23.070 --> 00:07:30.120 Mark Kushner: Alex, who is the Alex leans like with the developer of zappos couldn't find any animal is producing electricity, so he went to Hong Kong. 41 00:07:33.420 --> 00:07:33.870 Mark Kushner: and 42 00:07:35.100 --> 00:07:47.760 Mark Kushner: After that we captured the chew zappos and crane we have a pretty consistent description of how a plasma can transport its own species, and also how the species are generated. 43 00:07:48.570 --> 00:07:54.660 Mark Kushner: And then we show mainly one case study today, which is the case of a plasma electro chemical settlement. 44 00:07:55.230 --> 00:08:02.100 Mark Kushner: So it's a humid are going plasma there is interfacing liquid water why such a system. 45 00:08:02.550 --> 00:08:11.550 Mark Kushner: Well, if you have done some plasma research you typically want to start with something simple an argon plasma why because are gone is a pretty. 46 00:08:12.120 --> 00:08:27.570 Mark Kushner: Nice and noble gas in many senses, because it can be described pretty pretty easily, and so we have taken an argon plasma an interface that water with additional complexity of water, because water is a very sophisticated molecule subscribe. 47 00:08:30.180 --> 00:08:41.340 Mark Kushner: Right so some background and motivation, so why plasma water interfaces in the first place well there is a rise in interest in generating. 48 00:08:41.730 --> 00:08:56.820 Mark Kushner: reactive oxygen and nitrogen species are so for multiple reasons that are, ranging from their antimicrobial properties and these infection, but also interaction with living tissues like whom these infections and similar. 49 00:08:57.870 --> 00:09:06.330 Mark Kushner: So this is a pretty interesting topic nowadays in the field of not only plasma medicine, but also water purification, which is a very important thing. 50 00:09:08.190 --> 00:09:09.570 Mark Kushner: Also, another important. 51 00:09:10.800 --> 00:09:14.040 Mark Kushner: factor that we should account is that making. 52 00:09:16.890 --> 00:09:34.770 Mark Kushner: plasma CC mother was very pressure is relatively cheap and easy, so you don't need very special equipment is probably the power supply is the master expansive component, but other than that is essentially just water, air or some noble gases like argon. 53 00:09:36.930 --> 00:09:54.000 Mark Kushner: How many methods do we have to produce a plasma liquid interface well, there are many phase three and it depends on where you're putting the electro the with respect to the liquid So the first methodology is called plasma in liquid and. 54 00:09:55.230 --> 00:10:00.690 Mark Kushner: Essentially, the electrode is immersed inside the liquid surface inside the liquid. 55 00:10:02.850 --> 00:10:13.800 Mark Kushner: And the plasma is formed between one electro than the other they're of underwater, of course, in this case the plasma has to break the liquid, which means. 56 00:10:14.460 --> 00:10:23.010 Mark Kushner: I mean we are talking about the breakdown strength of a megabyte per centimeter so it's it's requiring a lot of energy, how do you decrease the energy. 57 00:10:23.400 --> 00:10:38.400 Mark Kushner: Well let's do a mixture of liquid and gases and that's the second season it's a bubble plasma system, but you still have the two electrodes, but you are those Ababa, so our gas phase inside the liquid, of course, the plasma will form. 58 00:10:39.120 --> 00:10:52.410 Mark Kushner: Inside the bubble first and then eventually affect the properties of the surrounding liquid the third methodologies, which will be what we'll be covering today and I will not be touching the other shoe. 59 00:10:53.520 --> 00:11:04.620 Mark Kushner: Is a plasma liquid interface, so you have one of the two electrodes which is outside the water at some decent somebody distance like a millimeter of the order of okay. 60 00:11:05.010 --> 00:11:13.830 Mark Kushner: So that the plasma forms inside the gas phase and the radicals and the Ionic species that are formed by the plasma to the electrons are. 61 00:11:15.600 --> 00:11:18.630 Mark Kushner: In the gas plasma face, it must be transported to the liquid. 62 00:11:21.210 --> 00:11:26.850 Mark Kushner: Now, before we go in more detail it's important understanding that this is a very sophisticated process. 63 00:11:27.690 --> 00:11:37.410 Mark Kushner: it's kind of easy to build the but also very complex to understand model why because they it's multi scale and move the physics under. 64 00:11:38.370 --> 00:11:48.090 Mark Kushner: Many different phases and many, many different reasons, so, for example, think about the electrons we think about the plasma systems, think about the letters first everytime know. 65 00:11:48.930 --> 00:11:57.810 Mark Kushner: So if i'm generating a plasma psychedelic with electrodes will be transported to the surface and at some point, they will enter into contact with the liquid. 66 00:11:58.140 --> 00:12:11.940 Mark Kushner: So there will be a layer or the interface, let me see if I can use the mouse here where salivated electrons we play some role and what do they do today to the liquid do they. 67 00:12:13.050 --> 00:12:18.390 Mark Kushner: dissociate the molecule what do they do, they produce radical so that's something that we have to understand. 68 00:12:19.980 --> 00:12:37.470 Mark Kushner: Second, after the electrodes we think about heavy heavy iron species or even new process all the articles and for the neutral species, you will have our salvation or the salvation processor, and the actual chemical balance that enters at some point they believe. 69 00:12:38.580 --> 00:12:49.410 Mark Kushner: In in the system will depend on what the product plasma produces and how the liquid surface is responding so as you understand it it's a problem that involves many different. 70 00:12:50.790 --> 00:12:59.040 Mark Kushner: components and when you construct a model like these into plasma plasma chemistry motor but it's not only plasma chemistry, there is much more than that. 71 00:12:59.760 --> 00:13:07.800 Mark Kushner: You need information and multiple levels so it starts from the top right Boxer where we have. 72 00:13:08.580 --> 00:13:18.780 Mark Kushner: Our electric birds up those which is sold in the plasma transporter and then crane which is technically separate the equation assembler. 73 00:13:19.500 --> 00:13:31.260 Mark Kushner: The resort in St for DNA differential equation systems and well, this is what we have been able to accomplish under the moves are 20 tenement framework but that's not the only piece of information. 74 00:13:31.890 --> 00:13:43.440 Mark Kushner: You need much more than death, if you want to describe properly the system and so at the intermediate scale, Sir, you want another a coefficient so how my. 75 00:13:45.240 --> 00:13:55.980 Mark Kushner: My species are interacting together which frequency and so, for that you need to find a way to come up with record feature answer so which species i'm, including in system. 76 00:13:56.580 --> 00:14:04.170 Mark Kushner: Which reactions, so how how the different species are interacting together, is there any methodology that I can use to. 77 00:14:04.710 --> 00:14:16.050 Mark Kushner: Take all the reactions classify them and use the same methodology to describe a bunch of reactions and, at the very end, come up with our regular feature that I can use it and you may be familiar with, because, like one more or less. 78 00:14:17.400 --> 00:14:27.450 Mark Kushner: or rmc they're essentially cause the camera informatics side of things that allow you to be some insight on the record patients, but even smaller times case. 79 00:14:28.260 --> 00:14:35.790 Mark Kushner: You have the quantum mechanical behavior of the system, so an individual molecule sometimes it's not very well known. 80 00:14:36.210 --> 00:14:48.720 Mark Kushner: And so you need to go and find, for example, deegan bodies of the molecule and for these you need something that is more first principle and we solving for the dfc the density functional theory problem associated to the. 81 00:14:50.790 --> 00:14:59.160 Mark Kushner: To the molecule you may be familiar because, like gosh and moorpark we use a PDF, which is a very straightforward a very nice color. 82 00:15:00.750 --> 00:15:04.710 Mark Kushner: Alright, so back in 2017 when we started looking at this problem. 83 00:15:07.200 --> 00:15:12.660 Mark Kushner: We had express Okay, how do we go about this problem, how do where do we start from and that's where we. 84 00:15:14.880 --> 00:15:19.650 Mark Kushner: When we found the moves finding tenements framework, so we selected this framework, mainly because. 85 00:15:21.270 --> 00:15:27.750 Mark Kushner: It offers a multi Kathleen environment where you can plug different pieces of physics together. 86 00:15:28.050 --> 00:15:39.480 Mark Kushner: So you can construct the art, but there are solving the cfd of the problem, together with the diffusion of extra reaction of the problem in the plasma chemistry, at a time Alex leans they are the. 87 00:15:41.310 --> 00:15:51.570 Mark Kushner: nc State University was working with a colleague Steve shine on purpose of China and he was working on this up those application in music. 88 00:15:53.100 --> 00:15:57.930 Mark Kushner: At the time there was no chemistry capability was not included, it was hard coded into the colder. 89 00:15:58.410 --> 00:16:04.710 Mark Kushner: So, thanks to some funding from the National Science Foundation, we extended the capabilities we did mainly two things. 90 00:16:05.460 --> 00:16:19.530 Mark Kushner: The first one was developing on plasma chemistry solver because that's necessary, and the second one was upgrading zappos and to the point that can handle arbitrary chemistry and arbitrary number of species all interacting together. 91 00:16:21.930 --> 00:16:32.190 Mark Kushner: One thing that he mentioned yet the codes are open Susan so you can go on github download them and use if you need them, and here, that are the Web links. 92 00:16:34.440 --> 00:16:45.960 Mark Kushner: Which equations that we sold the exact are Sir it's a brief the fusion reaction problem so it's essentially a fluid moment for a multi species plasma, where we have. 93 00:16:47.760 --> 00:16:55.650 Mark Kushner: The continuity equation for the species density, then an energy equation for for the electron Sir. 94 00:16:56.670 --> 00:17:00.510 Mark Kushner: A prescription for the flax seeds, which is, including my abilities and diffuse et. 95 00:17:01.230 --> 00:17:08.970 Mark Kushner: And then everything is linked through the persona equation so every charged species is contributing to the writing side of the equation. 96 00:17:09.630 --> 00:17:21.420 Mark Kushner: Is this enough well if you try to do these in a final element framework try to do that it's a good exercise it doesn't work, so you need proper boundary conditions and proper treatment for the transfer parameters. 97 00:17:22.140 --> 00:17:34.080 Mark Kushner: So the boundary conditions that we are using are taken from a target or three mentor and there are three boundary conditions, one for the electrons one for the heavy species and one for the energy, the one for the energy is missing. 98 00:17:34.770 --> 00:17:50.340 Mark Kushner: And most important thing is the the actual rights so i'm the way that the different species in a plasma liquid system interact together is mainly we have collisions so. 99 00:17:50.730 --> 00:17:55.890 Mark Kushner: an equaliser, can be terrible chemistry can be plasma chemistry can be many things so having. 100 00:17:56.850 --> 00:18:07.320 Mark Kushner: A sufficiently of ether, the description of the actual rate is quite important and that's when we did the we train and which is essentially taking a general expression of a multi. 101 00:18:07.770 --> 00:18:25.050 Mark Kushner: Two or three body, the accelerator and offering to the user an easy way to do the implementation, because a practical problem that you always find when you have a problem, like visa is that for bloggers have more than let's say a few types of species or. 102 00:18:26.400 --> 00:18:39.360 Mark Kushner: Few hundreds of reactions begins to be very cumbersome implementation is difficult and it's very prone to make mistakes Okay, and some point that you get out of Santa you don't know if the result is correct. 103 00:18:40.410 --> 00:18:50.190 Mark Kushner: Okay, do you have a mistake in my reaction networker do I made for getting a sign is this moving from one species or the other, of the other way around, so it's very prompt mistakes. 104 00:18:50.820 --> 00:19:02.400 Mark Kushner: So what you find in a paper is a table like in the format on the top right so it's a table with a list of reactions and their corresponding re Patricia into. 105 00:19:03.480 --> 00:19:13.380 Mark Kushner: What you implementing craner it's pretty much the same so ingrained and you still have a list of reactions, we should be human readable you define a list of species. 106 00:19:13.740 --> 00:19:25.740 Mark Kushner: You define the list of reactions and their corresponding reaction rates so if everything is coming from the integration of the letter energy distribution function, then you point to simply to the file containing information. 107 00:19:27.930 --> 00:19:35.130 Mark Kushner: will also be upgrades to saboteurs are we very quickly in the next three or four slides because I want to get to the plasma, let me sell. 108 00:19:36.300 --> 00:19:54.300 Mark Kushner: Mainly accepting a number an arbitrary number of species, we have tested a few other species and it's still working fine, then we are the surface charge accumulation if we're working on a DVDs they let your body these charges, so this is a very important thing to have in the model. 109 00:19:55.530 --> 00:20:04.440 Mark Kushner: And then we included the heavies PC salvation and evaporation and I will be skipping the following three slides because are giving details on these three points. 110 00:20:06.570 --> 00:20:19.200 Mark Kushner: I just want to find attention to the salvation of operation boundary condition, because this is critical for plasma liquid interfaces so the way that we handle that these is using a local henry's low. 111 00:20:19.680 --> 00:20:25.320 Mark Kushner: Okay, so we don't have any assumption on the bike densities or anything it's locality interface. 112 00:20:25.950 --> 00:20:36.840 Mark Kushner: And so we have to define the heavy coefficient on the interface for a human species or in and find a way to evaluate that but that that's a plus we have a flux equality condition for the mass partners. 113 00:20:38.550 --> 00:20:42.330 Mark Kushner: Once you develop a code that the first thing that you do is. 114 00:20:43.860 --> 00:20:51.000 Mark Kushner: You want to answer the question is my quick producing the right results right, so this step is technically called verification. 115 00:20:51.660 --> 00:20:55.980 Mark Kushner: And we did a very large number of certifications for crane alone. 116 00:20:56.400 --> 00:21:05.160 Mark Kushner: Doctors alone and the juicy things combined in here on left the you ever called based on of crane us as a standalone plasma chemistry sober. 117 00:21:05.490 --> 00:21:12.570 Mark Kushner: Against zte plus skin if you're working plasma chemistry, you might have already use that code, the code coming out from France. 118 00:21:13.560 --> 00:21:28.590 Mark Kushner: For a simple argon plasma on left or right, excuse me, you have a comparison of zap the screen versus the standard one dimensional DVD tutorial coming from the plasma module of console. 119 00:21:31.020 --> 00:21:42.900 Mark Kushner: Typical workflow so first you define the geometry up here and the Germans, we can be defined in a number of ways, typically gma she's a very convenient way it's very simple as a software. 120 00:21:43.560 --> 00:22:05.550 Mark Kushner: Or you can use kubi or live mesh and then you feed the these information into the moves environment where musi is essentially overseeing the interfaces between doctors and crane crane typically requires information from both glasser, especially for the species and reactions that are. 121 00:22:06.840 --> 00:22:22.950 Mark Kushner: kinetic and what do you get them to sign up with you get densities flux is conference in October, so everything that any food more than giving it provides now back in 2018 we did the workshop at the gashes electronics conference. 122 00:22:24.090 --> 00:22:27.480 Mark Kushner: On the on the day before the conference, I think it was a Sunday. 123 00:22:28.710 --> 00:22:36.390 Mark Kushner: which was a hand on workshop with people coming with a laptop or we installed all the software and we ran few few examples. 124 00:22:37.710 --> 00:22:49.650 Mark Kushner: Now the good thing from this workshop is that the material is freely available, so you can go and find the sequence of 500 slides which you can use it as training material for the for the software. 125 00:22:49.980 --> 00:22:59.070 Mark Kushner: And they can be found both from my our website or Professor Seamus website so that's very useful as a as a training material. 126 00:23:01.500 --> 00:23:10.530 Mark Kushner: Right, so when we set up the plasma liquid modelling services and crane we don't want to show that you think separately traditional approaches typically use. 127 00:23:11.640 --> 00:23:17.550 Mark Kushner: A model for the plasma a model for the surface either liquid solid and they tried to. 128 00:23:18.570 --> 00:23:27.300 Mark Kushner: Essentially interface that shoe at some level, but here we have the same identical model for both regions, so all the. 129 00:23:29.460 --> 00:23:40.860 Mark Kushner: All the passages your information from one model to the other or not even necessary because it's essentially solving the plasma water interface all at the same time is especially useful for from a chemistry perspective. 130 00:23:42.600 --> 00:23:48.030 Mark Kushner: Alright, so let's go to the exciting case study that I want to present today it's a plasma electrochemical session. 131 00:23:49.260 --> 00:23:59.460 Mark Kushner: So first let's have a look at experiment and how we build the applause manager chemical sense it's very simple, so you take a class you partially feel the glass with water via united water. 132 00:24:00.720 --> 00:24:09.300 Mark Kushner: And then you put a pin electro that could be literally a theme methodological made of things stealer some distance from the front of water, like a millimeter. 133 00:24:10.050 --> 00:24:23.250 Mark Kushner: And then you want to control the gas inside his glasses, so you put a later and then you feed them by automating some way with a gas that you like, in this case will be using our GM. 134 00:24:24.240 --> 00:24:31.260 Mark Kushner: And then you buy us the need Ola using a DC power supply which typically requires a bala bala resistor here. 135 00:24:32.640 --> 00:24:48.870 Mark Kushner: Now, in order to close the car Equator the Ionized water is not conductive so you need to add some salt or some something that is improving the productivity of the liquid in a controlled fashion and we added 20 millimeters of normal solid. 136 00:24:50.640 --> 00:24:55.290 Mark Kushner: You can open it discharge, and these boards and you can operate the the surgeon to moans. 137 00:24:55.680 --> 00:25:07.290 Mark Kushner: And now the versus cathartic depending on the polarity of the electrode so here, you have to Nice features from experiment taking with a microscope but because the gap is only one millimeter going from. 138 00:25:07.980 --> 00:25:12.810 Mark Kushner: The theme of the electrode which is visible here, up to the surface of water, which is down here. 139 00:25:14.070 --> 00:25:18.750 Mark Kushner: Now, if you have a negative polarity what happens well let's try to. 140 00:25:20.160 --> 00:25:21.420 Mark Kushner: Start understanding what happens. 141 00:25:23.130 --> 00:25:37.500 Mark Kushner: So the the counter these negative academy spoiling the electrons to the surface, so there will be an electron flow going from the plasma or gas region to the surface, well, we will find that the electrons. 142 00:25:38.970 --> 00:25:51.630 Mark Kushner: once they reach the surface, they solvay's pretty quickly, and so they remain there they speak and form essentially a layer which we will be calling the layer of salivated electron Sir, which has deep implications in the chemistry. 143 00:25:53.250 --> 00:25:58.320 Mark Kushner: The other way to discharge is the Antarctica which so you instead of using a negative. 144 00:25:59.550 --> 00:26:13.470 Mark Kushner: potential use a positive positive potential of the electrode and say to think what happens inside the plasma, well, it will be pushing all the positive ions pieces to the water and pulling electrons to worry electrode. 145 00:26:14.490 --> 00:26:30.330 Mark Kushner: So all the heavy iron species, now has have a preferential way to be pushed into one specific did actually inside the water, the water itself, it will be acting as an electric meter so there will be implications, also on these on the chemistry. 146 00:26:31.680 --> 00:26:41.730 Mark Kushner: Now, when you start a plasma chemistry model, you have to take decisions, especially for the species and that's the difficult part that which species i'm including my plasma condition moment. 147 00:26:42.570 --> 00:26:58.950 Mark Kushner: Now for a system like these, where we have our governor and water, we have to take decisions on what to track inside the plasma gas phase inside the liquid, and here the result Easter of will be included so for Dr garner we have both. 148 00:27:00.000 --> 00:27:08.790 Mark Kushner: are going plus or can shoot blaster for the charts pieces and you met a stable state lumped together in the in the neutral known. 149 00:27:09.510 --> 00:27:20.730 Mark Kushner: For the new service, we also have to include are going to class so, then the first class or foreign is actually very, very important water is the critical part of it so describing water is very difficult okay. 150 00:27:22.380 --> 00:27:39.300 Mark Kushner: So we included the old the major positive and negative radicals of water for the plasma portion but those inside the water portion clusters were track it up to the H3 or plus level so that's on hayden o'neill yona. 151 00:27:41.580 --> 00:27:47.370 Mark Kushner: Even if we know of a day for example classes are forming in the gas phase, much more than that, especially beyond situation. 152 00:27:49.440 --> 00:28:06.690 Mark Kushner: And then you have to make a decision which reactions to include the the results that I will be showing are coming from a model of 300 reactions for the gas plasma face and about 70 reactions for the for the water face and i'm not going to read all of them. 153 00:28:09.810 --> 00:28:14.940 Mark Kushner: Right, so we started looking at the results so first the flow structure and temperature. 154 00:28:16.530 --> 00:28:31.740 Mark Kushner: So here you have an accuracy metric caught up on a two dimensional plane of the of the system, few hardware things so, so there is a glass to you, but that is kind of easy board here. 155 00:28:32.400 --> 00:28:40.440 Mark Kushner: And then, at the Center of the pain electro the argonne is coming through the tuba through the gas tube as any lead from the top. 156 00:28:42.090 --> 00:28:42.870 Mark Kushner: and 157 00:28:44.040 --> 00:28:52.620 Mark Kushner: So from the cfd sober we have a solution for the field that for the velocity feeder inside a gasser any say the liquid. 158 00:28:53.580 --> 00:29:02.730 Mark Kushner: Inside the liquid that there is a comeback, it says that there is for me it's very slow it's in the media meters per second ranger willing the gasser it's moving a little faster in CG meters per sacrifice. 159 00:29:04.050 --> 00:29:09.720 Mark Kushner: One interesting thing is temperature so in such a system, you have the tip temperature the REACH is pretty high. 160 00:29:10.710 --> 00:29:18.780 Mark Kushner: Pretty high conditions it's the order of 1000 calvin's but then it's interfacing with a gas are going in Oregon is not a very good conduct or. 161 00:29:19.200 --> 00:29:30.180 Mark Kushner: tournament speaking, and so the temperature drops pretty quickly to the point that would have surface doesn't work much only few Calvin degrees so and it's true sponsored by the conversation. 162 00:29:31.890 --> 00:29:37.080 Mark Kushner: So let's start looking much more in detail what happens between the electrode and. 163 00:29:37.650 --> 00:29:45.660 Mark Kushner: In the water layer So here we are reducing the domain at to a one millimeter domain in the plasma in 10 microns in the liquid. 164 00:29:46.260 --> 00:29:56.550 Mark Kushner: And we are looking essentially along a vertical line that is moving from the electro that to the water in the chief animation you have an example of discharge evolution. 165 00:29:57.360 --> 00:30:09.750 Mark Kushner: That is showing or left the plasma phase, so these guys plasma phase or rise, the liquid water, the speed attention to the electrodes and it will be coming back or seen a sequence. 166 00:30:11.340 --> 00:30:17.820 Mark Kushner: slide on these so electrons eventually reach a steady state inside the plasma, which is coming from, because the neutrality of the system. 167 00:30:18.120 --> 00:30:25.350 Mark Kushner: But who can say the liquid, these are a discharge operating cathartic mold so the categories pulling pushing all the like pros towards surface. 168 00:30:25.950 --> 00:30:33.840 Mark Kushner: So why there are the surface and three is a very high concentration of electoral see several orders of magnitude larger than the plasma. 169 00:30:34.320 --> 00:30:46.560 Mark Kushner: Why, because then I can simply accumulator the sword phase and they form these layer of salivated electrons which is sitting there and eventually the density of electricity, so the liquid exponentially decays. 170 00:30:50.460 --> 00:30:59.310 Mark Kushner: Then, even before thinking about the species of the plasma one wants to think about delay the electric condition so what's the potential was electric. 171 00:30:59.310 --> 00:31:00.540 Mark Kushner: field inside the discharge. 172 00:31:01.530 --> 00:31:05.040 Mark Kushner: Because that offers a way to think about the. 173 00:31:06.450 --> 00:31:11.430 Mark Kushner: The transport of the species here, you have the plasma domain on the left. 174 00:31:12.660 --> 00:31:19.710 Mark Kushner: or right for the shoe overeating or no and all the services quality look at the potential, which is the the topper. 175 00:31:22.710 --> 00:31:23.490 Mark Kushner: Applause here. 176 00:31:24.810 --> 00:31:28.380 Mark Kushner: And we're looking again are along the line that goes from the lecture that. 177 00:31:30.150 --> 00:31:36.660 Mark Kushner: Now feature, the most important feature that we're interested is the castle the folder so when most of the potential. 178 00:31:38.400 --> 00:31:43.500 Mark Kushner: And for analytical operational person right in front of the sort of the world. 179 00:31:44.880 --> 00:31:46.710 Mark Kushner: Wide for preparation. 180 00:31:47.670 --> 00:31:48.150 Mark Kushner: According to the. 181 00:31:50.340 --> 00:31:54.240 Mark Kushner: occasion own where the electric temperature we've been teasing much. 182 00:31:55.470 --> 00:31:57.840 Mark Kushner: More and eventually how the chemistry. 183 00:32:10.950 --> 00:32:14.010 Mark Kushner: Inside the water, the potential drop is a little more. 184 00:32:14.730 --> 00:32:18.660 Mark Kushner: About a fraction of all the 0.0 we see sponsor. 185 00:32:19.410 --> 00:32:20.700 Mark Kushner: You say inside the water. 186 00:32:23.970 --> 00:32:26.460 Mark Kushner: So when we look at the electron temperature. 187 00:32:28.440 --> 00:32:34.980 Mark Kushner: And these are very important feature, the two modes offer a completely different profile of an interim temperature they. 188 00:32:35.400 --> 00:32:45.630 Mark Kushner: it's it's quite intuitive and we say because they they follow the the carpet folder because we were they electric field is the largest they use again, most of the average electron energy. 189 00:32:46.140 --> 00:32:53.910 Mark Kushner: So for cathartic operations, the peak electron temperature is close to the copper wait for an article operations is right in front of the surface. 190 00:32:54.480 --> 00:33:06.030 Mark Kushner: Okay, so these are already telling us that, for an article operations, most of the radicals of the plasma will be forming in front of the surface versus for catalytic operation and it's the other way around. 191 00:33:07.350 --> 00:33:26.040 Mark Kushner: So so informative looking at the profile of evolution of the species over time because disease telling how much for keeping species, the plasma is producing and how that is transported into the liquid eventually so to start from capacity corporations. 192 00:33:27.990 --> 00:33:45.360 Mark Kushner: So for a cathartic operations is quite interesting behavior because the density of the beginning during the break down phase, time is in the nano seconds Here are two seconds here in the science of nano cycle range the density in the Catholic faith begins to spike. 193 00:33:46.380 --> 00:33:56.010 Mark Kushner: And jumps into 10 to the 20 per meter Cuba range at that point, the current The self regulates because the ballast resists or begins to. 194 00:33:56.730 --> 00:34:14.340 Mark Kushner: leave me the discharge, and there is a characteristic time for transit of the ionization wave that is starting from the cathode it's arriving to the liquid is establishing the car rental policy resistor is taking taking off and then the discharge begins to be sunny very good. 195 00:34:16.890 --> 00:34:23.850 Mark Kushner: Eventually the chemistry, such that the most abundant positive species is the hydro pneumonia so the glass of water. 196 00:34:25.380 --> 00:34:33.990 Mark Kushner: For a Nordic operation, so we don't have that ionization waiver and socially intuitive because this piece is already forming close to the surface and so. 197 00:34:34.290 --> 00:34:44.250 Mark Kushner: You don't allow the spike in densities to occur, so they the densities are growing essentially monotonic it for most of the species, except for few. 198 00:34:45.300 --> 00:34:45.840 Mark Kushner: and 199 00:34:49.110 --> 00:35:01.650 Mark Kushner: yeah so for for the water barter is the issue, plus or writer, the most abundance pieces that you're serving water for cathartic operations is H two. 200 00:35:02.250 --> 00:35:16.440 Mark Kushner: And four day an article creation so that's a competition between hydrogen hydrogen peroxide and oxygen, so there are multiple species that are forming inside inside the water doing an article operations and. 201 00:35:17.280 --> 00:35:22.710 Mark Kushner: So the question could be at this point that okay how this partial profile looks like. 202 00:35:24.090 --> 00:35:40.680 Mark Kushner: And here, there is the density of few selected species as a function of the vertical coordinator, so in a cathartic operations inside the gas we for mainly hydrogen peroxide and hydroxide so H2 or H3. 203 00:35:41.880 --> 00:35:45.870 Mark Kushner: The quality neutrality of the plasma is established, mainly by the high drama. 204 00:35:46.980 --> 00:35:47.820 Mark Kushner: With a. 205 00:35:48.930 --> 00:36:00.090 Mark Kushner: very small deviations from quasi neutrality, except right in front of the sources, where there is a deviation of 5% so the plasma becomes mildly electro negative close to the surface. 206 00:36:02.190 --> 00:36:13.950 Mark Kushner: You know the corporation steal the species are the most abundant species are hydrogen peroxide and I hydroxide but no let's look at what happens inside the water, because this is telling us something. 207 00:36:15.150 --> 00:36:22.230 Mark Kushner: For the qatari case electrons for a layer of submitted electrons so that's the blue a black for. 208 00:36:22.950 --> 00:36:32.370 Mark Kushner: In in the case, but when we look for electrons indiana case we don't find much not on these range of 10 cities so they. 209 00:36:33.060 --> 00:36:50.460 Mark Kushner: They sit have submitted electrons in another case it's much smaller okay these already telling me something, because when electrons have a strong reducing agent a property, so if I operated discharging two different modes, I can play. 210 00:36:51.630 --> 00:36:56.220 Mark Kushner: With electrons I can use electrons you know very. 211 00:36:57.690 --> 00:37:01.680 Mark Kushner: You know very targeted way to essentially producers PCs versus destroy that. 212 00:37:03.990 --> 00:37:11.880 Mark Kushner: Then from the analysis of the actual mechanism where we analyze the mean the actual pathways that we've been able to construct. 213 00:37:13.140 --> 00:37:27.030 Mark Kushner: The reaction mechanism for clinical operations so and that's the way they were it's essentially a way to go from a very complicated plasma chemistry model of more than 300 species down to very simple reaction mechanism. 214 00:37:30.120 --> 00:37:41.310 Mark Kushner: So ions are bombarding the cathode and imaging secondary and throws the secondary electrons are essentially sustaining the discharge, they can either Ionized our governor or. 215 00:37:42.510 --> 00:38:00.420 Mark Kushner: Or do another two or three processes that are afraid of is that better we mentioned later so let's try to follow the branch after our guns i&i is that it has very high probability of participating in our free body reaction which you need for alarcon's forming a relationship last. 216 00:38:02.430 --> 00:38:09.240 Mark Kushner: know are going to plus is a very large charges change cross section, with a vote water molecule so that. 217 00:38:10.620 --> 00:38:26.160 Mark Kushner: Now we can form an H2 hopeless at that point that the molecule has two pathways I can follow can either interact with me like throwing to be dissociated into oxygen and hydrogen are can. 218 00:38:27.210 --> 00:38:32.850 Mark Kushner: He asked me the hydrogen molecules and form a hydro nehemiah and said, plus atomic hydrogen. 219 00:38:34.830 --> 00:38:39.840 Mark Kushner: Then let's go to the other branches so let's start again for the electrodes of the sword face. 220 00:38:40.470 --> 00:38:55.860 Mark Kushner: And let's see what happens when they collide our water molecule well, they can discuss it diva ionization is is is an important, in fact, there is a very large cross section and which is forming hydrogen invoice miles so then. 221 00:38:56.850 --> 00:39:16.020 Mark Kushner: hydrazine at these range of temperatures, is a very large cross sections for electronic attachment it's okay for each mind when it's a interacting with an electron each miners can also interact with water with water molecule forming always miners and again hydrogen gas in the gas face. 222 00:39:17.460 --> 00:39:21.600 Mark Kushner: Most of the times, however, electronic simply excited article without are uniting it. 223 00:39:22.170 --> 00:39:33.330 Mark Kushner: In here and using our gold star as just a symbol for the metal stable Oregon that is formed out of the process and the metal stable can carry around energy. 224 00:39:33.990 --> 00:39:50.850 Mark Kushner: So the argument, a stable has some probability, which is not negligible it's pretty high to interact with a water molecule and D excited or better transfer that energy to dissociate the molecule so our goal goes back to mute rolla and former. 225 00:39:52.140 --> 00:39:54.750 Mark Kushner: dissociated monitoring tweets hydroxyl. 226 00:39:55.920 --> 00:39:57.870 Mark Kushner: Radical radical in hydrogen gas. 227 00:39:59.400 --> 00:40:11.250 Mark Kushner: Then Oh, he can interact with another O H in a free body processing Morgan also one are gonna toner forming hydrogen peroxide which can collide with one electrode and former. 228 00:40:12.300 --> 00:40:22.590 Mark Kushner: Always radicals in different kind of different charge, then the oh he begins to go into self limiting cycle with hydrogen peroxide. 229 00:40:23.130 --> 00:40:40.560 Mark Kushner: And they essentially begin to feed each other so always the excuse me, the destruction of hydrogen peroxide is for middle age, which is for me again hydrogen peroxide and that's why we see, we saw that the two most abundant species are peroxide and O h. 230 00:40:43.200 --> 00:40:50.910 Mark Kushner: Reading an article operation a reaction mechanism is a little similar, but there are few fundamental differences now. 231 00:40:52.110 --> 00:40:57.060 Mark Kushner: The main difference physically speaking, is that the positive electrode is pushing the is to have the surface right. 232 00:40:57.750 --> 00:41:14.580 Mark Kushner: And so electrons are moving upward that will the positivity bias electrode and the most important is probably that in another corporations that are no, so this is like, for us, or at least no significant amount of submitted electrodes of the interface, and this has consequences because. 233 00:41:15.780 --> 00:41:26.550 Mark Kushner: Now older articles forming the gas by the plasma can be sold in boulder Okay, they have higher probability of having a longer life was the disorder. 234 00:41:27.390 --> 00:41:41.640 Mark Kushner: And so inside the water we begin to see H two O H hydrogen peroxide in larger quantities, there is also some production of molecular oxygen in water through a reaction involving the age of shoe. 235 00:41:43.620 --> 00:41:58.560 Mark Kushner: What you find inside the water during the preparation in green quite quite expensive, I would say is more liquid oxygen when I call an oxygen because it's essentially working like in a connection and literally Dixon where an article operations are for me. 236 00:41:59.760 --> 00:42:14.880 Mark Kushner: oxygen and cathartic hydrogen so that point we said Okay, we can predict hydrogen peroxide let's see if it's working so we started a collaboration with professors and kind of be the system, and he confirmed that. 237 00:42:15.960 --> 00:42:19.830 Mark Kushner: Yes, there is a good way to measure hydrogen peroxide that in. 238 00:42:21.000 --> 00:42:39.180 Mark Kushner: In a reliable way, so we started looking at the generation mechanism of hydrogen peroxide another important thing is that hydrogen peroxide is useful for these infection so probably I told my you have used hydrogen peroxide multiple times when you have to disinfect the moon, or something. 239 00:42:41.460 --> 00:42:48.480 Mark Kushner: So from from the motor, we see that hydrogen peroxide is mainly producing the gas phase me from the you h. 240 00:42:49.590 --> 00:43:08.220 Mark Kushner: O H, as I discussed in the previous natural mechanism can count from metal stable our goals are who are going to star or Asia to now from the modal we see a very significant difference in the concentration of the peroxide inside the liquid. 241 00:43:09.360 --> 00:43:18.750 Mark Kushner: And that's a blotter right so doing an article operation we have four orders of magnitude of hydrogen peroxide more with respect to cathartic that's a pretty large difference. 242 00:43:19.800 --> 00:43:27.210 Mark Kushner: And the results have something more that we can learn from the model because, from the difference between cathartic and an article operations. 243 00:43:27.660 --> 00:43:34.620 Mark Kushner: You know where the electron temperature is high gear and so you can also have a clue on where the. 244 00:43:35.070 --> 00:43:43.170 Mark Kushner: monster boone and arguments PCs in the plasma phase we are present, that we start eventually triggering the reaction mechanism for the production of radicals. 245 00:43:43.680 --> 00:43:54.210 Mark Kushner: And in fact in another corporation So you see that are gone Star and are going to plus or for me right in front of the water surface, the first the very first things of micrometres. 246 00:43:55.230 --> 00:43:57.720 Mark Kushner: In also hydrogen peroxide is speaking there. 247 00:44:02.010 --> 00:44:03.660 Mark Kushner: And then we started also the. 248 00:44:05.460 --> 00:44:15.810 Mark Kushner: did last mechanisms, because Okay, we are producing hydrogen peroxide in the gas phase, but once he arrives the liquid what happens in here you have a table. 249 00:44:16.710 --> 00:44:25.860 Mark Kushner: between them, that is, essentially, highlighting the three most dominant last night running for hydrogen peroxide inside the liquid phase. 250 00:44:26.760 --> 00:44:36.330 Mark Kushner: And for an Audi operation, so we see that hydrogen peroxide is essentially dissociated or consumed by hydrogen or H1 and H2. 251 00:44:37.020 --> 00:44:41.610 Mark Kushner: And there is no significant mechanism of production of these pieces inside the water okay. 252 00:44:42.600 --> 00:44:54.660 Mark Kushner: Well, for cathartic operation, Sir, hydrogen peroxide is carbons it by electrodes on mine was an age, but most likely by electrodes. 253 00:44:55.470 --> 00:45:06.930 Mark Kushner: Okay, so we did a control simulation running a cathartic qasr artificially turning off that reaction that single reaction that is destroying hydrogen peroxide. 254 00:45:07.500 --> 00:45:24.960 Mark Kushner: And that's what you see in the on the plot so for cathartic operation with the food network, you see the classical layer of surveys and electrons which is exponentially decaying we turn off that reaction, so the scavenger outrun of hydrogen peroxide we don't you see. 255 00:45:26.040 --> 00:45:29.880 Mark Kushner: dramatic increase in the proxy concentration inside the water. 256 00:45:31.110 --> 00:45:44.400 Mark Kushner: And so, when I describe these a film my son state, but is there any way that you can take away all the electrons and and that's the idea behind this controlled experiment. 257 00:45:46.140 --> 00:46:01.110 Mark Kushner: And so, in this experiment, we are essentially running the same cathartic discharge using or better adding an electoral scavenger and we use sodium nitrate for that na No three. 258 00:46:01.860 --> 00:46:14.340 Mark Kushner: Any MP3 once he's saying in the acquisition fully dissociate into any plus and No three minus in the liquid phase, and the resulting onions, and every minute Sir. 259 00:46:15.150 --> 00:46:33.870 Mark Kushner: are very eager to eat electrons so they they want to become an free to minors so Professor son cannot run these experiments, together with me cheaper with very controller quantities in the Milli Molar range of. 260 00:46:35.460 --> 00:46:46.350 Mark Kushner: sodium ninth writer in capacity condition, Sir, and at some point about the critical pressure that you see the concentration of hydrogen peroxide skyrocketing so that means that. 261 00:46:47.280 --> 00:47:03.510 Mark Kushner: The Saudi room nitrate onions are scavenging the electrodes on the distributor electrodes on the surface and at that point, the surface is no longer acting as a barrier and the species producing the gas phase can be sold in the water. 262 00:47:05.910 --> 00:47:18.720 Mark Kushner: And then we need a separate that far they're looking at concentrations and comparing the concentrations coming from the mobile versus the concentration from experiments that are mainly two ways to come to well probably more. 263 00:47:19.740 --> 00:47:34.350 Mark Kushner: To measure hydrogen peroxide in a liquid and it's a using GIs or four in the million dollar range and another say the fox say in the micro Molar range is much more sensitive but it's. 264 00:47:35.190 --> 00:47:43.290 Mark Kushner: Looking at the micro Molar range and when we try to do this comparison, I mean there is a very sophisticated procedure in order to do this. 265 00:47:44.490 --> 00:47:55.380 Mark Kushner: We find that as a function of time and, as a function of the discharge carbine that you have a pretty much leaner increase of the concentration of the peroxide in the liquid. 266 00:47:56.340 --> 00:48:06.450 Mark Kushner: And and that's pretty much in agreement with a with the simulations and then we can also think to scale these with respect to car, and so the plot on the top on the. 267 00:48:07.110 --> 00:48:20.790 Mark Kushner: bottom is the production rate of a hydrogen peroxide per unit car rent in the discharge, we have another estimate from the simulations of 22% that we are today to the experiments. 268 00:48:21.960 --> 00:48:22.800 Mark Kushner: and 269 00:48:24.030 --> 00:48:29.220 Mark Kushner: But it's pretty much a satisfactory result So how do we summarize everything. 270 00:48:30.360 --> 00:48:49.140 Mark Kushner: So what have we learned today when when we open it a plasma liquid interface, we can control the amount of hydrogen peroxide by operating the discharge which shoe polarities with opposite polarities so when we overlay the surgeon or Qatar de moda. 271 00:48:51.090 --> 00:48:59.550 Mark Kushner: electrons are pushed by the castle toward the surface, polygamy service where they speak and they essentially form a wall I call it the electron Warren. 272 00:49:00.240 --> 00:49:07.950 Mark Kushner: So if you're producing hydrogen peroxide in the gas phase, and that is produced very close to the car to work, the legend temperature is larger. 273 00:49:09.030 --> 00:49:23.580 Mark Kushner: When that hydrogen peroxide first has to be transferred to the surface and then has to cross the wall, but that one is a very eager to destroy the molecule so when you find inside the liquid is just the oil so it's the broken molecule. 274 00:49:24.870 --> 00:49:33.750 Mark Kushner: But if you reverse the polarity when that's a very nice way to have ideas and products, I mean a liquid solution produced by a plasma why. 275 00:49:34.140 --> 00:49:42.180 Mark Kushner: Because the electron temperature peaks right in front of the surface so most of the articles are phone there, which is where you want them. 276 00:49:42.690 --> 00:49:57.600 Mark Kushner: And there are no service electrons so you can deliver much more efficiently hydrogen peroxide to the water and indeed that is confirmed by his payments, where we find a very significant and dramatic difference between cathartic and analytics. 277 00:50:00.570 --> 00:50:09.930 Mark Kushner: Right So to conclude that I have done a quick overview of crane and zappos, which are two applications that you're free to use we're happy to have people using the colder. 278 00:50:10.230 --> 00:50:24.450 Mark Kushner: So if you're interested or you have a plasma chemistry problem, please take a look at crane and that those are open source there is training material online that you can use to learn the code. 279 00:50:25.470 --> 00:50:39.360 Mark Kushner: And then it's presented sure one application one application of cleans up this to a plasma liquid interface or four plasma triple H is silent and i'm not going to repeat the difference between an audition cathartic I hope. 280 00:50:40.770 --> 00:50:41.220 Mark Kushner: This comes from. 281 00:50:42.300 --> 00:50:46.920 Mark Kushner: We this relate to thank you for the attention and we'll be happy to take any questions. 282 00:50:54.090 --> 00:50:57.780 Mark Kushner: very much a sprint seminar are the questions. 283 00:51:00.270 --> 00:51:16.260 Mark Kushner: year I mean like like using doing the same experiment, by changing the temperature of the water to see it now like if there's more you know embracing other you like more hydroxide in the water, the. 284 00:51:17.310 --> 00:51:25.680 Mark Kushner: temperature definitely plays a role, and we have to control the temperature we, I mean experimentalism have to control the temperature very I don't control. 285 00:51:27.870 --> 00:51:37.560 Mark Kushner: And they they use a thermometer to make sure that the temperatures increased much in the US so have optical diagnostic studies looking specifically at the temperature. 286 00:51:38.400 --> 00:51:49.260 Mark Kushner: Especially because we're interested in calibrating the temperature and transport component of the model against experimental measurements, we have a paper just about that. 287 00:51:49.710 --> 00:52:05.790 Mark Kushner: it's essentially making a very important point that even if the electrode is warm enough, but then 1000 calvin's the surface temperature of the water doesn't change much in temperature goes up to 10s of calvin's degrees kelvin degrees when i'm much more than that. 288 00:52:06.810 --> 00:52:13.800 Mark Kushner: We haven't tried to repeat experimenter as a function of temperature of the water that would be a Defense for sure yeah. 289 00:52:17.760 --> 00:52:21.090 Mark Kushner: Question so in the model itself to. 290 00:52:22.500 --> 00:52:30.990 Mark Kushner: You address electron transport, so this is one big deal with is that Catholic or negative. 291 00:52:32.340 --> 00:52:37.410 Mark Kushner: And second question is like we run with and then. 292 00:52:38.610 --> 00:52:39.060 Mark Kushner: Potentially. 293 00:52:40.860 --> 00:52:58.410 Mark Kushner: Some patterns and that suggests that there is always there but it sounds like maybe it's not much of default based on right so for the transport of electrons we have several estimates for the dishes DVDs and the transport parameters of the electrons in the liquid. 294 00:52:59.790 --> 00:53:09.510 Mark Kushner: which I didn't ask whatsoever, but they are being a big important part in component of the of the worker, so the electrons can diffuse into the liquid that. 295 00:53:10.350 --> 00:53:22.080 Mark Kushner: There is a very dramatic change in issues evenly between the gas plasma face and the liquid remember bodies, but in our in the 10 or 10 to the minus nine meters square per second ranger so it's a very. 296 00:53:23.280 --> 00:53:24.450 Mark Kushner: Very low dishes ability. 297 00:53:26.970 --> 00:53:36.210 Mark Kushner: For the other question I think we can address that the the the the cell structure and the and the patterning of the plasma only with a 3D model which we didn't do. 298 00:53:38.040 --> 00:53:53.430 Mark Kushner: If it's just transport or chemistry, or even we can capture that if it's something else i'm not sure about that I think when i'm not very familiar with the structure that you're talking about, but it became the must be the during life structures right all sorts. 299 00:53:54.780 --> 00:53:57.390 Mark Kushner: yeah cuz we're assuming that there's like an old. 300 00:53:59.370 --> 00:54:04.260 Mark Kushner: model show that alton shop is like is it is like 10 bucks. 301 00:54:06.570 --> 00:54:10.620 Mark Kushner: In the gas face is much more than than the teaching the mega with ranger. 302 00:54:12.390 --> 00:54:17.880 Mark Kushner: At the analytics so you have probably six eight megabits per meter. 303 00:54:24.360 --> 00:54:36.630 Mark Kushner: Oh yeah in the capacity case that the reason small drop in front of your face but it's so much, I must have the drop most of the catalog for ladies happening in front of electoral votes in that case 10s 10 megabit per meter. 304 00:54:41.400 --> 00:54:53.670 Mark Kushner: fireball surface plasma surface of the water when you're running successfully making a lot of plasma yeah it could be also any faith connected today. 305 00:54:54.750 --> 00:55:03.240 Mark Kushner: Probably a sad face instability that is happening because they have water molecules are colonizing in front of 10 megabits per meter electric fee that. 306 00:55:03.630 --> 00:55:11.940 Mark Kushner: Now that point, you can sustain a continuous ventilator static structure right there in front of electric field that and probably so it's causing some. 307 00:55:12.540 --> 00:55:25.380 Mark Kushner: capillary waiver that is interface with a with electrons there or the species, the chance pieces, that would be an interesting problem for a 3D simulation like this, like. 308 00:55:26.790 --> 00:55:34.950 Mark Kushner: yeah that's another interesting feature so changing from one day to 2d to 3D it's a geometrical change so in trainings outdoors it's a. 309 00:55:35.760 --> 00:55:51.150 Mark Kushner: But these are very common featuring means you don't have to change anything else about that, but the geometry all the rest of the model doesn't change you spend four weeks in Brighton these hundreds of flying files, but you don't have to change it. 310 00:55:54.750 --> 00:55:55.230 Mark Kushner: For the. 311 00:55:56.550 --> 00:56:09.720 Mark Kushner: scenario, if he introduced sodium nitrate with that i'll break down that electron electron wall, and you know it doesn't do much you know actually in the simulations we included or something fluoride. 312 00:56:11.370 --> 00:56:13.470 Mark Kushner: chloride, the mind fine night right. 313 00:56:14.490 --> 00:56:21.630 Mark Kushner: Yes, yes, and you got the point so that specifically they controlled experiment that we did here. 314 00:56:25.980 --> 00:56:34.260 Mark Kushner: yeah so by changing the concentration of nine fighter at some point you're scavenging, although the electrons, including the electrons are the interface. 315 00:56:34.830 --> 00:56:49.410 Mark Kushner: And then you see the concentration of the radicals forming the gas face to be larger significantly larger posting the liquid, and so there is a way to scavenge the electrons are using an additional chemical yes. 316 00:56:55.740 --> 00:56:57.000 Mark Kushner: Any other questions. 317 00:56:59.280 --> 00:57:00.930 Mark Kushner: If not there's a question. 318 00:57:02.910 --> 00:57:17.190 Mark Kushner: teacher model on different barbiturates suppose that again better under, is it possible to use your bottle for different water matrices that like contain organic matter, for instance for with the model breaks down at that point. 319 00:57:18.870 --> 00:57:32.610 Mark Kushner: Is it possible to use the model for other matrices including organics but one or the other yeah no, I think, no, because that needs to be extended, there is no organic chemistry in the model. 320 00:57:34.110 --> 00:57:42.300 Mark Kushner: So, accounting for anything that is connected to organic chemistry requires a specific section in the model that is not included. 321 00:57:43.890 --> 00:57:53.820 Mark Kushner: And I think it's highly problem dependent, I would say, so if you're tackling I don't know body nursing water versus some financing water that would be probably independent. 322 00:57:56.310 --> 00:58:00.210 Mark Kushner: There is a question from john hey john can you hear me. 323 00:58:01.200 --> 00:58:02.580 John Verboncoeur: Yes, I can thank you. 324 00:58:03.000 --> 00:58:03.360 I. 325 00:58:06.840 --> 00:58:14.910 John Verboncoeur: don't know if that I think that must be on your side, so thank you for a nice talk to me, I have a question about the interface. 326 00:58:15.390 --> 00:58:19.950 John Verboncoeur: Between the water and the gashes phase, in particular, you showed a number of densities. 327 00:58:20.190 --> 00:58:31.050 John Verboncoeur: it's hard by the eyeball to add up the the current continuity, you know, without knowing also the velocity distributions along with those densities, but i'd love to see the divergence. 328 00:58:31.380 --> 00:58:37.650 John Verboncoeur: Of the occurrence as a function of position in the water, to see if there's a buildup of charge at the surface. 329 00:58:37.920 --> 00:58:41.340 John Verboncoeur: And in transverse buildup of charge, due to the profile. 330 00:58:47.610 --> 00:58:49.020 Mark Kushner: Okay, can you still hear me. 331 00:58:49.320 --> 00:58:49.860 John Verboncoeur: Yes, I can. 332 00:58:50.370 --> 00:59:00.060 Mark Kushner: Okay yeah that's that's the point that we actually analyzed and consider that, and especially for capacity corporation, we have found that there is. 333 00:59:00.600 --> 00:59:11.310 Mark Kushner: A mind V electro negative behavior of the disorder which is not present in an RD condition, Sir, and as you move to where the surfaces charger charging. 334 00:59:12.540 --> 00:59:19.920 Mark Kushner: Because the neutrality is broken by which amount they can mention the results, because it on a call, but there is a. 335 00:59:21.000 --> 00:59:25.950 Mark Kushner: A large deviation from cozy neutrality inside the California yeah. 336 00:59:26.700 --> 00:59:42.000 John Verboncoeur: So, so that that divergence I think when can involve with the velocity distribution might be very interesting signature or something going on, because it, you also noted, for example, high charge transfer cross sections between between argon two plus and water molecule so. 337 00:59:42.150 --> 00:59:50.460 John Verboncoeur: One could imagine the opportunity for large deposition and large buildup of charge and polarization of the water, maybe following. 338 00:59:53.310 --> 01:00:04.170 Mark Kushner: Yes, that's a good point, yes, I think that that's something that can potentially be looked with the moderator it's already there with doesn't require any additional running it's just another feature to look at. 339 01:00:04.410 --> 01:00:05.730 John Verboncoeur: yeah very good Thank you. 340 01:00:06.270 --> 01:00:06.720 Thank you. 341 01:00:08.160 --> 01:00:08.610 Mark Kushner: one. 342 01:00:12.930 --> 01:00:14.580 Mark Kushner: Vision vision. 343 01:00:16.530 --> 01:00:16.800 Mark Kushner: What. 344 01:00:18.810 --> 01:00:19.920 Mark Kushner: is the one that you guys. 345 01:00:22.350 --> 01:00:41.280 Mark Kushner: Water is a dielectric electrical speaking with electric primitives your feet you wanna I mean it's a typical value for the boundary conditions well the the we have several and have different natures needs nature so did our boundary conditions for the lateral flat says. 346 01:00:44.520 --> 01:00:45.960 Mark Kushner: he's coming from the first equation. 347 01:00:47.370 --> 01:00:49.440 Mark Kushner: For the feed, we have. 348 01:00:51.270 --> 01:00:55.230 Mark Kushner: yeah so for the persona equation, and let me go back to the sketch. 349 01:00:56.430 --> 01:00:57.150 Mark Kushner: Okay. 350 01:00:58.650 --> 01:01:10.980 Mark Kushner: So we are setting the applied voltage and abundance resistor and then there is a voltage are the car or the electric plasma interface, that is coming from the secret equation. 351 01:01:12.030 --> 01:01:27.180 Mark Kushner: Okay, so it's taking other given Nice and, in time, the current density, which is coming from the contribution of all the charts pieces arriving at that location integrating data over the aria and essentially solving for the syrup with equation. 352 01:01:29.460 --> 01:01:39.510 Mark Kushner: of equilibrium of we observe a different voltages for the different operating conditions and, for example, for a typical decides which were just worried. 353 01:01:40.260 --> 01:01:50.460 Mark Kushner: That report here we have a car to fall off around the three of us around 300 minus three and avoid Sir so that's but that's not a boundary condition is coming from the secret equation. 354 01:01:50.970 --> 01:01:58.860 Mark Kushner: Okay, and for the analogy between the 400 it's the apply voltage depends on the plasma Convent have experimented. 355 01:01:59.160 --> 01:02:16.440 Mark Kushner: It seemed the range it's around 2500 balls, but it can be changed because we control the current experiment and depending on the carton and you're using We said we said that um and then it's grounded on on the on the liquid very good sized city soon. 356 01:02:20.550 --> 01:02:21.270 Mark Kushner: Thank you very much. 357 01:02:27.840 --> 01:02:32.160 Mark Kushner: Important procedural issue right outside the room there is food. 358 01:02:34.500 --> 01:02:40.710 Mark Kushner: very late late late lunch early dinner, the second poster session will begin at five o'clock.