Skin Definition and 157 Threads

People usually dislike people with big birthmarks (I mostly mean sexual attractiveness, but not only). It seems that the presence of moles correlate with something bad in the organism. With what? Is that possibly that the moles can correlate with bad features of character? I have found the...

I feel 12 years old asking this. Your nails grow. Isn't the skin attached to the underside of the nail? Why doesn't it pile up at your finger tips? It doesn't, so that must mean your nail slides over the skin like a glacier over land?

Scientific American June 2, 2022 Vol 32 Number 6 Page 62 Title: Skin Cancer around the World Two Quotes: “The main cause of skin cancer is the exposure to the sun’s ultraviolet rays…” “UV radiation is about 40% stronger in New Zealand than it is at corresponding latitudes in the Northern...

My work Q= 0.025 * 4190 * (34-100) = -6910 but on chegg but did they do Q= 0.025 * 4190 * (100-34) = 6910. I thought the initial is 100C and final is 34 because it goes from 100 to 34

In vibroacoustic therapy does the transducers have to be touching the skin ? I get that power is lost in the air, but it is enough to matter ?

When you try to create time varying magnetic fields in solid metals, there is severe heating due to eddy currents, when you increase the frequency, just like in NDT(non destructive testing) the magnetic field is pushed away from the core to the periphery due to eddy currents opposing the field...

However, I can't find any proof on this ? Can someone help to explain this ?

Homework Statement:: Not a specific question, more just a conceptual clarification for a project. But generally: What is an equation for the effective skin depth of a multilayered (in this case only 2 layers) wire, as a function of the resistivities and relative permeabilities of both of the...

London penetration depth that's defined for superconductors has a similar equation to skin depth in conductors derived from maxwell's equations. Are they equivalent?

That's it, just the question. I am figuring that the tarnish is an irrelevance as it does not participate either magnetically or electrically, so any RF current passing through the [still metallic] silver top layer, albeit with tarnish over the top, will pass through the same thickness of...

Why is it generally accepted that black skin is only caused by melanin, due to the intensity of UV radiation, in order to protect the body from skin cancer to develop? Because melanin is also, together with adrenaline, linked to the precursor: dopamine, thus both chemicals share the same pathway...

I herd about this, is it true. Is eating clams or oysters good for mens skin?

Hi, Its my first time here in PF, I was wondering what could be a fast endothermic reaction(with water) that does not burn the skin/ cause severe allergic reactions when/after touching or in contact with the reaction. (With high rate of cooling and hopefully no bubbles or gas forming). E.g to be...

I was reading about why blue eyes look blue. After all, the human body does not create any blue pigment. It turns out, it's the same reason the sky is blue: the Tyndall effect. When there is minimal pigmentation, the first frequencies of light to scatter are the blue frequency waves. When there...

Hello, I have an unusual case in that I am using XRD to study plant skins before and after certain chemical treatments. So the resulting pattern will have a lot of amorphous regions but also some characteristic peaks showing the presence of fatty acids, etc. Basically I grind everything to a...

if the human skin consists of hydrogen, then why does not happen hydrogen bond through contact with something or with another person?

This may be one of those things that everybody knew but me (come to think of it, I think I'll add it to the "things I learned today" thread elsewhere). There are some plastic bags I use which come on a roll. I have been struggling to open them when I remove a bag from the roll, rubbing...

If you have fillings (such as from iron dusts or carbon fiber) stuck in your skin? would it eventually join with your blood flow? What is the filter system of the blood where it couldn't accept the smallest particle and how big is the particle? Imagine iron dust filling or 1 carbon fiber...

Has anyone got thoughts/opinions on the brush applicator for the product being a bit unsanitary? Just saw it, and the cut in the model's hand is being "painted" shut/closed with a brush that is obviously being returned to the bottle. Is there not potential for wound fluid(s) to...

recently i saw a thread where skin depth was mentioned (I guess in one of my own threads) and then it got me thinking, well imagine we have a rather thick wire thick enough so that for a given frequency there is almost no current running in the middle of the wire due to skin effect. let's take...

I'm studying conductors, where complex wave number ##K=k+iα## and complex index of refraction ##N=n+iκ## is introduced. My textbook(Fowles Optics) says that for "very low frequencies", skin depth δ is equal to ##δ=\frac{1}{α}=\sqrt{\frac{λ_0}{cπσμ_0}}##. What is "very low frequency"? How much...

Hello, I am trying to figure out how much the human skin temperature would increase when the skin is illuminated by radiation of a certain intensity (W/m^2). We can assume that the skin has an emissivity and absorptivity both equal to 1. For instance, imagine the skin illuminated by the sun (I=...

A little complicated and interesting story, I will get down to the point: I need a number of substances that cause skin rashes/skin redness or overall has a bad reaction to human skin. This is all for research purposes for natural skin products me and a group of friends are developing.

Hey, guys. There is something interesting about the skin effect, which also made me curious:wink:. Could you please help to solve it? The following is what I got from Wiki. It is said that, according to theory of induction, induced current would oppose the change of magnetic field. Then when...

Hello, is there a common name/word/terminology for any protective layers on an organism, for example, skin on humans, bark on a tree, etc?

Hi folks, I want to build a heater similar to this http://www.thermon.com/us/products.aspx?prodid=10 , using a ZVS power supply from ebay (such as this one -http://www.ebay.com/itm/381569526996?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT) ) As well I would like to replace...

hi, nowadays I try to get involved electromagnetic waves equations, and I came across that $$ \nabla $$ is treated like $$ ik $$ and $$ \frac {\partial } {\partial t} $$ is treated like $$ -iw $$ And if you look at the part painted with orange in my attachment, afterwards you can see that $$...

I see 2 commonly quoted maps for distribution of native human skin colour. Both are old; they have a lot of odd divergences - as well as many matching features, some of which are hard to explain. One is Biasutti, 1940: https://upload.wikimedia.org/wikipedia/commons/8/81/Map_of_skin_hue_equi.png...

A conductor with a large high frequency AC current causes a "Skin Effect" meaning that most of the current flows at the surface of the conductor. What does the skin effect look like if you have a conductor with one side flattened? And what does the resulting magnetic field look like? See...

First of all, hello. I have a problem in understanding the skin effect. Often I read, that the skin effect is directly caused by eddy fields inside the conductor, which oppose the "desired" current flow. Problem at this is, that the eddy fields are not in phase with the desired current. The...

Homework Statement Amoung soap and detergent,which is more harmful to our skin? Homework Equations None The Attempt at a Solution Soap is what we use for bathing so if it is harmful we wouldn't have used it.The detergents are used for washing clothes more often. So I think detergents are harmful.

If I use 10mm (thickness) of a metal for the sides of a Faraday cage, with a 5mm skin depth at the frequency to be shielded, & increase the v/m of the EM wave to be blocked gradually, will there be a stage where the skin depth will increase to 6mm, or is 5mm the maximum limit?

Is it possible for skin to hold a negative or positive charge on one part of the body, such as the back of a hand? How does this occur? Thank you

Hi, I need to run wind tunnel tests on a simple shape which will be made of foam whilst the skin friction is to be negligible. Is there easy ways of cover the model to achieve this ? thanks

For a good conductor, an incoming plane electromagnetic wave will be attenuated exponentially as it penetrates a distance ##z## into the conductor, ##|\vec{E}(z)| = |\vec{E_0}|e^{-z/ \delta}##. ##\delta## is called the "skin depth". The current generated by this incoming electromagnetic wave is...

Hello, My name is Chris and I am trying to understand why UVA radiation, with a longer wavelength, penetrates deeper into the skin than UVB which has a shorter wavelength. Since E=hv=hc/ λ and , then how does a lower energy and lower intensity UVA wave penetrate deeper into the skin than a...

[Mentor's Note: Thread moved from New Member Introductions] Hello, My name is Chris and I am trying to understand why UVA radiation, with a longer wavelength, penetrates deeper into the skin than UVB which has a shorter wavelength. Since E=hv=hc/ λ and then how does a lower energy...

I modeled honeycomb core and face sheet seperately now i want to add or glue them to make a sandwich but it shows error so how can i join them.anyone please

Is it possible for an organism to evolve with skin stronger than bone? theoretically? As in, a humanoid only instead of strong bones, it has strong skin? Would that make sense biologically? Thank you for any aid!

Hello everyone, thank you for helping me in the other post, this one is different but includes pressure and how to calculate how much of it is present when an object is being "indented" or dug into. I come from a forum that discusses fictional characters a lot and we find it highly enjoyable to...

Hello. The skin depth is nothing but measure of penetration depth of EM Wave when it is incident on the conductor. It is well known that the skin depth is decreased when the EM wave frequency increases. But thinking about DC field. We know that when DC is applied to metal (metal is installed...

Homework Statement A thin metallic strip on a circuit board has length L, width a and thickness t, with L>>a>> t. Derive an expression for the resistance between the ends of the strip at frequency f, assuming that the skin depth is small compared with the thickness t. Homework Equations The...

is skin effect of ac due to eddy current?

I am desperate with an assignment and i would be grateful if someone could answer the following question. I read about skin effect and skin depth and i found the following one. "The skin effect depends upon the nature of material used for the conductor diameter of the wire, frequency, shape of...

Skin Effect: . where = resistivity of the conductor = angular frequency of current = 2π × frequency = relative magnetic permeability of the conductor = the permeability of free space ------------------------------ From Wiki According to Skin Effect, the higher the frequency, the less...

Homework Statement i) At rest a 70 kg person with an area of 1.7 m2 consumes around 14 litres of oxygen per hour. Around 2% of this is provided by diffusion through their skin. Calculate the diffusion rate for oxygen through human skin, in millilitres per second per square metre. ii) What...

I am very interest in knowing about how skin reduced force that can damage bone. I guess it act like a protective layer by flexing and stretching such as a trampoline. Also skin redistribute the force and spread out evenly and the soft tissue play role here too. Please help if someone have any...

Hello forum, I have a few doubts on EM. 1. The skin depth formula for constant current(DC) shows that there can be current uniformly distributed through the cross-section of a conductor.However as there can be no electric field within a conductor(as per Maxwell's equations) there can be no...

I read that essential oils can go through the skin. I am told that there are more water molecules in just 10 drops of water than stars in the whole universe, so if they are so tiny, why don't they go through the skin membrane pores, which are perfectly visible under an optical microscope? You...