Membrane Definition and 148 Threads

How did you find PF?: by searching If I have an old 5000 lt pressure tank and as I see it needs a change of its membrane (Bludder) what is the recommendation that must be followed and also what is the volume ratio between the membrane before using and after testing or working situations

Hello everyone, All living things have a growth cycle in which they gain mass and volume. These elements are obviously and undoubtedly taken from the environment in which these creatures live. Therefore, it is undeniable that the amount of potassium, for example, in the body increases during...

1.If the thickness of soap water surface decrease, whereas the concentration remain the same, how will the surface tension change? 2. If the membrane of soap water start to evaporate, its thickness become thinner and it’s concentration increase, How will the surface tension change? Thank you!

Hello everyone, I am studying the physiology of the kidneys and in all of the textbooks they say basolateral membrane referring to the basal membrane, does anyone know why we don't just say basal membrane?

Hey guys, I just wanted to know if you think that a membrane field theory could ellucidate the non-perturbative framework of M-theory? Let me specify and explain what I mean by that: String field theory was intoduced to study the non-perturbative regime of string theory and some achievements in...

Hi guys, I am able to solve dif equation of passive membrane model. But later, author says following instructions to integrate first model. Even though I can solve the dif equation of model, I couldn't achieve the solution. Could you help me pls. Best regards.

Good evening, I got a seriously problem at understanding the membrane potential for ions in a cell. Particulary, i don't understand the case for example for ions with a charge of 2 or higher. I take a look on two scenarios: If you got an ion like calium and got a concentration ratio of 1:10...

I am having problems writing the initials conditions.

When anodizing aluminium (or Titanium) a dense hexagonal pattern of microscopic pores is formed, and you can get a pretty high aspect ratio with them. But the illustrations always show the oxide layer with pores on top of a pure aluminium layer. But can you oxidize a thin sheet of material so...

My attempt, Considering that it jumps in the maximum compression position: $$\frac{kA^2}{2} = mg(H+A)$$ replacing k / m with w ^ 2 : $$A^2 w^2-2gA-2gH=0$$ Solving the second degree equation: $$A=\frac{2g+\sqrt{4g^2+8gHw^2}}{2w^2}$$ But the answer is...

Given 4 spaceships are pulling an elastic rubber membrane with constant speed and slow velocity into an asteroid belt. - In that way, that they all start in empty space and have a constant low speed of say 50km/h as they reach the belt. - The four edges of the membrane are tied to one of the...

My attempt: p and T allows us to calculate ##Z=402 \frac{kg}{sm^2}## using ## Z=p*\sqrt(\frac{\gamma*M}{R*T})## . The sound intensity level at 10 meters allows us to calculate the intensity at 10 meters to be I=10``````^{-7} W/m^2 using ##50 = 10*log(I/I_0)##. Then, using the formula...

Actually i am trying to see what the first equation to the entropy means, maybe N1 remets to the part 1 (the left suppose) of the system? (or the molecules type 1?) I am not sure about the equations i will do below, probably it will be wrong, anyway. ∂S/∂U1 = 1/T1 = 3NR/2U1 Okay, it will give...

Please give me clues as to how to solve this question. The answer provided is (c).

Hi All, I considered filing a patent for this invention, but instead decided to publish it so people could use it to advance the state-of-the-art in drums. You don't need to add tape or pillows to your drum heads to muffle the overtones. Using tape or pillows also kills the strike of the...

Let's try inputting a solution of the following form into the two-dimensional wave equation: $$ \psi(x, y, t) = X(x)Y(y)T(t) $$ Solving using the method of separation of variables yields $$ \frac {v^2} {X(x)} \frac {\partial^2 X(x)} {\partial x^2} + \frac {v^2} {Y(y)} \frac {\partial^2 Y(y)}...

what are the main concepts of membrane theory? the most beautiful possible giresults. g → 1/g where g is the coupling constant ive read that this transformation changes a dirichlet membrane into fundamental strings. does this have something to do with evaporation of black holes?

We have a small (15 X 25mm), thin membrane (0.03mm thick) that we currently inspect for pinholes and small cracks manually by backlighting and inspecting under magnification, one at a time. Does anyone know of an instrument that can do this inspection for us, with a high degree of accuracy?

Homework Statement Not sure if this is the appropriate place to ask this question, but I didn't know where else to ask. Anyway. Let's assume that I have a film (or membrane) material that is stretched over some boundary, (lets assume a thin hollow cylinder). Then some constant force is...

Hello, natural frequencies of (circular) membrane are expressed in every textbook as: where is the m-th positive root of the Bessel Function of the first kind of order n. For m=1, n=0: ξmn = 2,405. represents the radius of membrane, and is the velocity of wave propagation...

Homework Statement A typical human cell is approximately 10 μm in diameter and enclosed by a membrane that is 4.2 nm thick. To simplify the calculations, model the cell as a sphere. 1) What is the volume of cell? (in μm^3) 2) What is the volume of cell membrane? (in μm^3) 3) Percent cell volume...

I am trying to anallytically determine natural frequencies ƒ of the tympanic membrane. I am using 2D sectorial annulus membrane as a simplified model of tympanic membrane according to following picture The parameters that i want to use are following: THICKNESS = 0,1 mm The natural...

Homework Statement An elastic membrane in the x1x2-plane with boundary circle x1^2 + x2^2 = 1 is stretched so that point P(x1,x2) goes over into point Q(y1,y2) such that y = Ax with A = 3/2* [2 1 ; 1 2] find the principal directions and the corresponding factors of extension or contraction of...

I am trying to solve for the theoretical relative decay rates of the various (m,n) modes of an ideal circular membrane, if that membrane is excited momentarily by an impulse or deformation. I would ideally like the decays of the (m,n) modes in dB/s. Imagine a simple isolated drum head being...

This little industry news article walks through how some researchers identified the channel proteins underlying a skate's (similar to a ray) electrosensitivity, which allows it to find prey buried in sand or otherwise obscured (heartbeats make weak electrical signals the animals can detect)...

I wasn't sure whether to post this in here or in computer programming, since it touches on both. I have a personal project that is based on a 2-dimensional finite-element fluid simulation (which already works just fine) but needs to be able to simulate an elastic membrane stretched across a...

I would like to understand this a bit better, so I am looking for a reference to refer to and not necessarily an explanation in a reply. I have a non-porous membrane of a compressible material wrapped around a solid body. I then draw out the air between the membrane and the solid body. I want...

I am aware of laminar flow but would like to look for some other ways. Is it possible to block ions from flowing in the "wrong" direction by applying a magnetic field to the electrolyte and let neutral molecules pass through?

Say I have a small solid polymer container filled with gas A. The walls of the container are semi-permeable, so gas A on inside can't get through/out. On the outside, gas B at atmospheric pressure, which can migrate through the membranes of container. Pressure inside the container is 0,6 bar...

I am in the process of trying to develop a modal drum synth. I have the following graphics as references for the frequencies of some of the first modes relative to the fundamental: This is a good start. But I want to be able to model more modes than just that. What is the formula required...

Suppose I apply a pair of equal and opposite harmonically varying forces perpendicular to an infinite drum membrane. Consider the following forcing functions at two nearby points,(x=0,y=a) and (x=0,y=-a), separated by a distance 2a, F(t,0,a) = Acos(ωt), F(t,0,-a) = -Acos(ωt) Let the forcing...

What is the process? And can/cannot it filter out?

Various sources describe the origin of the eukaryotes as occurring when a bacterial cell ingested an archaea cell, which then symbiotically became the nucleus of the created cell, and which was then the LUCA (Latest Universal Common Ancestor) of all the eukaryotes. The cell membranes of the...

Is it possible to 3d print a neuronal structure with a different material than neurons that would work just like a neuron with membrane potential?

Hello, I have recently picked up drumming and the topic of tuning has peaked my interest. I have gone over numerous sources (academic theses, Wikipedia, HyperPhysics, etc.) trying to piece together what is occurring when drums (right now tom with two heads, batter and resonant, are of most...

Hi, I have a rectangular membrane (material: laminated aluminum like food packaging). The membrane is clamped around perimeter. From one side I have uniform (gas) pressure. The membrane is constrained from another side with rigid plate and, hence, do not deflect. But I can measure force that...

I have a question about membrane distillation. I have read the following from a review paper about membrane distillation: The membrane distillation should be applied for membrane operations having the following characteristics: - The membrane should be porous. - The membrane should not be...

Hi! I found a nice thing via google for a measuring forces by using a light pipe. The light gets coupled into a light pipe and the amount of light is measured by a diode (http://www.dr-iguana.com/prj_LightPipe/). I think you can also use such a device for measuring the deflection of a membrane...

I have been wanting to write an equation which predicts the tension on a circular membrane (AKA drumhead). However, I'm not sure that my answer is on the right kind of track, if it's even correct. As for the procedures I took, first I started with the equation for tension on a string, which I...

Is there an existing equation, or set of equations, that directly links the specific vibration of a superstring filament with the resultant particle mass? A brief explanation of any mathematics would be helpful. Thank you.

Hello, I will be doing an experiment to separate N2 from O2 in air using membrane separations. I need to write my own experimental procedure to find the objectives of the experiment. Here is our experimental set up I'm trying to figure out how to do objective i. I need to figure out the...

What is the best source for understanding the membrane polarization effect in rocks??

Nucleus - Double membrane Nucleolus- no membrane Chromatin- no membrane Nuclear Envelope - Double membrane Smooth/Rough Endoplasmic Reticulum -single Membrane Golgi Body- single Membrane Central Vacuole- single Membrane Lysosomes - single Membrane Chloroplasts - Double membrane Mitochondria...

I am quoting from wikipedia https://en.wikipedia.org/wiki/Endomembrane_system "In eukaryotes the organelles of the endomembrane system include: the nuclear membrane, the endoplasmic reticulum, the Golgi apparatus, lysosomes, vesicles, endosomes and the cell membrane." From this question arises...

Homework Statement This is not a homework or anything similar, but it is a problem I am trying to solve and I don't know how to start. I do know, that the most stable structure in 3D is a sphere - that is the reason why the drops are in a spherical shape. But now imagine a rectangle and...

Is it possible to switch the porosity of any microporous material by external stimuli (eg. optical, pressure or electrical ). I'm trying to imagine something akin to an "Artificial Stomata" where the pore opening & closing Can be externally controlled. I'd be very thankful if someone could...

I believe I know the answer to this question; I need an expert to verify it for me. I work for a company that makes latex balloons. The people that have been here for a long time insist that if one is putting a small (5" balloon) filled with helium inside a larger (30") balloon then one must...

Homework Statement A string is sewn in a 2D membrane. What is the amplitude of the reflected wave? All the parameters you need in order to get to the result are known. Homework EquationsThe Attempt at a Solution Ok, so we have a 2D membrane, with a string at ##x=0## along the the ##y## axis...

Homework Statement Find stationary state of a circular membrane, on which a coin is put. Homework EquationsThe Attempt at a Solution I am not sure about the second boundary condition, so if any of you has the time, please check the following solution: $$u_{tt}=c^2\nabla ^2u+\rho g$$ Where...

Hello, Suppose sinosodial AC and pulsed DC magnetic fields with equal rms are applied on animal cells in the presence of magnetic nanoparticles. For the mean field strengths to be equal, the peak value of the square wave (with 50% duty cycles) must be sqrt. 2, which means that the maxiumum...