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Selker and Or: Soil Hydrology and Biophysics
United States
เข้าร่วมเมื่อ 7 ก.ย. 2018
6 - Overview of ADE solution: sorption, degradation, and Gaussian solution to transport to the ADE
This is a longer video (14 minutes) that covers how an instantaneous injection into a media is transported, as predicted by the advection-dispersion equation, including linear degradation, and linear sorption.
มุมมอง: 1 353
วีดีโอ
6.5.1 Colloidal transport (Selker)
มุมมอง 6634 ปีที่แล้ว
Colloids are micron-scale particles which can be mobile within the vadose zone ands in aquifers. Though small, they can have very large portion of the total surface area in a soil, and are generally highly reactive. Solutes frequently sorb to colloids, and if the colloidal particles dissociate from the soil grains, this can mobilize those sorbed compounds. This can move compounds, such as heavy...
6.2.4.1 Dani and John Discuss dispersion
มุมมอง 6674 ปีที่แล้ว
Drs. Selker and Or discuss the occurrence of dispersion and diffusion in the vadose zone. They point out that, in contrast to aquifers where movement can be meters per day and dispersion is the most important spreading process, the very slow movement of water in the vadose zone implies that diffusion often dominates spreading. They also clarify the confusing terminology that authors use in desc...
2.5.2.3 Dani and John discussion retention functions
มุมมอง 6184 ปีที่แล้ว
Here Drs. Or and Selker talk about the fine points of selecting a mathematical model to describe soils. What issues should you think about when choosing a model for soil-water behavior? Advantages and disadvantages of the van Genuchten, Brooks-Corey and other representations are discussed informally.
2.1.5 Dani and John discuss REV and scales
มุมมอง 6194 ปีที่แล้ว
The "Representative Elementary Volume" or REVB is a fundamental underpinning of describing flow through porous media. Here Dani and John talk about this important concept in a discussion format, relating the REV to scaling ideas, fractals, and watersheds.
1 3 3 The Gouy Stern layer and cation exchange in Clays
มุมมอง 1.3K4 ปีที่แล้ว
Dr. Selker speaks about the interactions of cations and anions immediately at the surface of clays, as well as in the water films attached to clay surfaces. These ionic attractions and repulsions control much of the chemical behavior of clays.
1 3 1 2 Families of clays (Selker)
มุมมอง 6264 ปีที่แล้ว
Clays take on vastly different character because of the underlying structural building blocks from which they are constructed. Here the major families of clays are presented, as well as the impact of the family characteristic on hydrological processes.
1 3 1 1 Silica tetra and octahedral drive clay properties
มุมมอง 2.1K4 ปีที่แล้ว
Dr. Selker speaks of the basic silica-dioxide structures that dominate clays. The differences between the tetrahedral and octahedral building blocks is shown to control much of the chemical properties of clay soils. Cation exchange capacity, surface area per gram, and other features are discussed.
1 1 A 4 minute history of continuum quantification of vadose flow (Selker)
มุมมอง 5014 ปีที่แล้ว
Dr. Selker describes the move from intuitive understanding of flow in porous media to the age of quantification of flow. We discuss the landmark achievements of the 1800's (Darcy, Boussinesq, Schlichter), and then the pillars of the 20th century, with Buckingham, Green and Ampt, Richardson, Richards, Haines and the Miller brothers.
1.1 A 4 minute history of complex processes in the vadose zone
มุมมอง 4764 ปีที่แล้ว
After the 1950's scientists began to see the role of macroscopic features of soils that gave rise to water flow and chemical transport moving far differently than described by equations and descriptions developed for idealized media. Fingered flow, macropore flow, and capillary barrier flow added rich new horizons to the understanding of the vadose zone.
1.1 A 4 minute history of ancient understanding of the vadose zone
มุมมอง 5994 ปีที่แล้ว
Dr. Selker reviews some of the remarkable historical context for understanding water movement in soils over the past 2,000 years.
7.5.3.3 Enhancement of Vapor Transport in Soils (Dani Or)
มุมมอง 6014 ปีที่แล้ว
7.5.3.3 Enhancement of Vapor Transport in Soils (Dani Or)
4.2 Surface Radiation Balance (Dani Or)
มุมมอง 3354 ปีที่แล้ว
4.2 Surface Radiation Balance (Dani Or)
2.5.2.3 Mathematical Representations of the Soil Water Retention Curve (Dani Or)
มุมมอง 4.1K4 ปีที่แล้ว
2.5.2.3 Mathematical Representations of the Soil Water Retention Curve (Dani Or)
6.0 Mechanism of Solute transport in Soils
มุมมอง 1.8K4 ปีที่แล้ว
6.0 Mechanism of Solute transport in Soils
1.2.3.3 Intro to Soil Structure (Dani Or)
มุมมอง 7684 ปีที่แล้ว
1.2.3.3 Intro to Soil Structure (Dani Or)
3 3 3 Estimation of van Genuchten parameters
มุมมอง 3.9K6 ปีที่แล้ว
3 3 3 Estimation of van Genuchten parameters
2 5 5 Geophysical methods in the vadose Zone - K. Singha
มุมมอง 7076 ปีที่แล้ว
2 5 5 Geophysical methods in the vadose Zone - K. Singha
2 5 2 3 1 Rien van Genuchten: Water retention and conductivity functions
มุมมอง 2.8K6 ปีที่แล้ว
2 5 2 3 1 Rien van Genuchten: Water retention and conductivity functions
6 0 1 Rien van Genuchten: Modeling of water and solute transport
มุมมอง 3.7K6 ปีที่แล้ว
6 0 1 Rien van Genuchten: Modeling of water and solute transport
2 4 6 1 Jesus Carrera: the concept of head when liquid density is not constant
มุมมอง 4436 ปีที่แล้ว
2 4 6 1 Jesus Carrera: the concept of head when liquid density is not constant
6.2.4.2 Jesus Carrera: Transport equation for porous media and how to deal with flux and velocity
มุมมอง 2906 ปีที่แล้ว
6.2.4.2 Jesus Carrera: Transport equation for porous media and how to deal with flux and velocity
6.2.4.1 Jesus Carrera: Advective and Diffusive Time Scales
มุมมอง 4576 ปีที่แล้ว
6.2.4.1 Jesus Carrera: Advective and Diffusive Time Scales
2.1.5.1 Michel Quintard part 2: upscaling variables
มุมมอง 4426 ปีที่แล้ว
2.1.5.1 Michel Quintard part 2: upscaling variables
2.1.5.1 Michel Quintard part 1: multi-scale media
มุมมอง 6696 ปีที่แล้ว
2.1.5.1 Michel Quintard part 1: multi-scale media
Que grandeeee mi causa, gracias
Eh, pretty sure they just mirrored the video horizontally, folks. He probably isn't doing superhuman writing. Just stating Occam's Razor here.
Really? I spent weeks and months learning to be right handed and writing backwards to make these videos. ... joking - you are right - the system flips the video to make the writing correct, but it does make me appear to use my right hand, whereas I am actually left handed.
This is very meaningful for a novice in scientific research, and thank you very much for sharing your knowledge！
Amazing, Thank you for you effort.
Nice！
Thank you for the greatest work! And how to find the e-book, the link is unavailable now, what a pity.
thank you sir for clear explanation
As one of the comments mentioned below, l is missing in the relative hydraulic conductivity equation I think.
Please can you share soil hydrology and biophysics
Very clear explanation Prof. Thank you !
thanks dude
This reminds me of the awkward silence you experience when someone you don't know is watching you work on something.
This is the first time I see a video filmed this way and I love it!
Brilliant! Did anyone notice how quickly he could write backwards?!
Muchas gracias por la explicación! solo un comentario, por favor cambiar de color del plumón, gracias
Why could I also do this in terms of the mass of water and the mass of soil if all depend on the volumes, those would depend on the density for that.
First, let's think about a soil that does not swell. In that case, the volumetric and gravimetric moisture contents are related by a single "conversion constant" (the bulk density - mass per volume). If the soil does swell, then you would need to have a function that describes how volume and moisture content were related, and the conversion would be a function of moisture content itself. Finally, if the relationship between volumetric and gravimetric moisture are themselves hysteretic (that is that for the same gravimetric water content, but for the cases where water content is increasing versus decreasing) then you would need to have another hysteretic mathematical relationship between the two water contents. I don't know of anyone who goes to this level, but it may well be needed for precise accounting for swelling soils.
Thank you Prof.!
there will be cos theta in the equation as we will take upward component of surface tension
Not in this first case, where the energy of the air-glass interface is larger than the combined air-water and glass-water energy - this gives a zero contact angle. For contact angle, see video 11 of this chapter: 2 5 1 5 Contact angle effects on capillary pressure.
Thanks for the info. This one video has at once answered many of my most complicated questions regarding nutrient uptake in the root system, in a surprising and pleasant way. ❤❤
Thank you 👍👍👍👌❤️ so much better than just memorizing
Dr. Selker- you are so inspirational!
Fantastic
I think the argument inside the degradation term should also be divided by R?
Thank you
you help me understand this confusing thing, Thanks for sharing sir!
what is the reference for this?
van Genuchten, M.Th. (1980). "A closed-form equation for predicting the hydraulic conductivity of unsaturated soils". Soil Science Society of America Journal. 44 (5): 892-898. Bibcode:1980SSASJ..44..892V. doi:10.2136/sssaj1980.03615995004400050002x. hdl:10338.dmlcz/141699.
Thanks you for sharing sir, very interested video topic
Thankyou sir, Love from India,🇮🇳
Very well explained , Thank you !
Super🎉! Really a good stuff❤
thx for this video <3
In what year U.S. net farm income swelled to $33.3 billion?
Hello, any one can help me by giving Modflow and Hydrus software for Macbook, thanks Well Explain You great concepts are clear now
Hi! Good information here. But aren't you missing the lambda exponent on the relative saturation term in the hydraulic conductivity function? I have literature that shows a lambda exponent on there, but its missing here, so just confused. Thanks in advance.
i think l (nomally 0.5) is missing there?
Thanks for this video - very helpful
Nope, still can't get past this guy writing backwards.....sourcery
My good sir, he is writing on a glass window with a camera filming him from the opposite side.
the best explanation !!!
Home take away is not to exceed the scale(REV) of applicability..
I'm amaze that he write everything mirrored. Different types of genius 🙌
thank you so much! Very clear and straight to the point!!!
clear and to the point!
Excellent, time of concentration of a pollutant
Perfect and simple
Nicely explained
Why is gravity neglected in the force balance?
it is displaced into p*pi*r^2
Gravity had to catch a train that day... ;-)
great video thank you very helpful
Hello, Thank you very much for this very useful and interesting video!! I have a question, how can I get the excel? Thank you again!
Good explanation sir
sir, your video about SWRC is very good. I am interested in soil water retention curve representation kindly send me a calculation spreadsheet in excel format.
It's cool that professor can write backward, and I read some definition (e.g. Maliva, R.G., 2019 ) is "unsaturated zone=vadose zone + capillary fringe"