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Topic: Ficks law of diffusion


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In the News (Fri 19 Jul 19)

  
  Math Forum Discussions
Re: Matlab - Solution of Ficks Second Law Diffusion Equation
Matlab - Solution of Ficks Second Law Diffusion Equation
The Math Forum is a research and educational enterprise of the Drexel School of Education.
mathforum.org /kb/thread.jspa?messageID=941818&tstart=0   (146 words)

  
  Fick's law of diffusion - Wikipedia, the free encyclopedia
Fick's laws of diffusion describe diffusion, and define the diffusion coefficient D.
Fick's laws of diffusion were derived by Adolf Fick in the year 1855.
Equations based on Fick's law have been commonly used to model transport processes in foods, biopolymers, pharmaceuticals, porous soils, semiconductor doping process, etc. A large amount of experimental research in polymer science and food science has shown that a more general approach is required to describe transport of components in materials undergoing glass transition.
en.wikipedia.org /wiki/Ficks_law_of_diffusion   (589 words)

  
 Wikipedia: Diffusion
In cell biology, diffusion is described as a form of "passive transport", by which substances cross membranes.
Diffusion is one kind of transport phenomenon: compare it, for example, to radiation.
In cell biology, facilitated diffusion is a process of passive transport; via which polar molecules diffuse across membraness, with the "help" of transport proteins.
www.factbook.org /wikipedia/en/d/di/diffusion.html   (669 words)

  
 Fick's law of diffusion: Encyclopedia topic   (Site not responding. Last check: 2007-10-09)
Fick's laws of diffusion describe diffusion (diffusion: (physics) the process of diffusing; the intermingling of molecules in gases and liquids as a result of random thermal agitation).
Fick's laws of diffusion were derived by Adolf Fick (Adolf Fick: adolf eugen fick (1829-1901) was a german physiologist and inventor....
Fick's First Law is used in steady state diffusion (diffusion: (physics) the process of diffusing; the intermingling of molecules in gases and liquids as a result of random thermal agitation), i.e., when the concentration within the diffusion volume does not change with respect to time (J
www.absoluteastronomy.com /reference/ficks_law_of_diffusion   (470 words)

  
 Diffusion
Diffusion is the mixing, in the absence of any chemical reaction or external force, that occurs when two fluids are placed in contact.
The term is also used figuratively to describe the spontaneous mixing of abstract entities such as ideas and cultures: see diffusion (anthropology).
In physics, diffusion is one process by which matter, heat or momentum moves from one place to another.
www.teachersparadise.com /ency/en/wikipedia/d/di/diffusion.html   (618 words)

  
 Fick's law of diffusion - TheBestLinks.com - Ficks law of diffusion, Diffusion, Gas, Membrane, ...   (Site not responding. Last check: 2007-10-09)
Fick's law of diffusion - TheBestLinks.com - Ficks law of diffusion, Diffusion, Gas, Membrane,...
Ficks law of diffusion, Fick's law of diffusion, Diffusion, Gas, Membrane, 1855...
Fick's law of diffusion is a law of the diffusion of a gas across a fluid membrane.
www.thebestlinks.com /Ficks_law_of_diffusion.html   (259 words)

  
 Wikinfo | Diffusion
Electric current flows by diffusion in most conductors.
In cell biology, facilitated diffusion is a process of passive transport; via which polar molecules diffuse across membranes, with the "help" of transport proteins.
Images, some of which are used under the doctrine of Fair use or used with permission, may not be available.
www.wikinfo.org /wiki.php?title=Diffusion   (726 words)

  
 [No title]
This law was first applied to study the diffusion properties of oxygen by Bohr (1909), and states that for blood transversing the lung capillary the total oxygen transport (V.O2) is proportional to the alveolar-lung capillary PO2 difference, i.e.
Indeed in studies using the MIGET the concept of diffusion impairment is seldom required to describe abnormalities in gas exchange, except in cases of pulmonary fibrosis (Agusti et al., 1991), exercise, or mild exercise during hypoxia (Torre-Bueno et al., 1985; Wagner et al., 1986).
Charles’ law and Boyle’s law, which together state that for a fixed mass of gas the pressure multiplied by the volume is proportional to the temperature i.e.
www.miba.auc.dk /~sr/bookchpt.DOC   (6689 words)

  
 [No title]   (Site not responding. Last check: 2007-10-09)
Imaging of the injected or infused drug agent is performed by MR diffusion mapping using the RF microcoils attached to the distal shaft of the injection device, or by imaging an MR-visible contrast agent that is injected or infused through the walls of the dialysis fiber into the brain.
The MR signal is dephased by the random motion of diffusing water molecules, and the presence of the delivered material locally affects the degree to which the amplitude of the signal is altered by the dephasing.
Diffusion has been determined employing radioactive or fluorescent tracers, in which the concentration profiles of the tracer are monitored over time, and its diffusivity is inferred from the data.
www.wipo.int /cgi-pct/guest/getbykey5?KEY=00/07652.000217&ELEMENT_SET=DECL   (11229 words)

  
 Freediving - Diving Physiology
The gaseous exchange of oxygen and carbon dioxide across the alveolar-capillary membrane occurs solely by a process known as diffusion and is governed by Ficks Law.
This law simply states that, because a large percentage of the human body is water, more gas will dissolve into the blood and body tissues as depth increases, until the point of saturation is reached.
Thus the diffusion rates of oxygen and carbon dioxide are much sharper, since there is a fresh flow of water passing through all the time.
freediving.dyndns.org /physiology.html   (4897 words)

  
 ME 482/582 Homework Two   (Site not responding. Last check: 2007-10-09)
In this situation, because we assume a steady state at the interface, the diffusion flux through the weld interface must be equal to the average flux of C down the concentration gradients on either side of the interface (whatever comes in one side of the weld region must go out the other).
WELD ZONE DIFFUSION: In the weld zone, the diffusion is being driven by two opposing driving forces; the concentration gradient (a flux to the left), and the partial molar free energy gradient (a flux to the right).
We can assume that diffusion only occurs due to the composition gradient, and that the partial molar free energy of C in the right side is constant (though it has a different value than the left side of the couple).
oregonstate.edu /instruct/me482/Homework/W06/ME482Hmwk2.html   (1917 words)

  
 BME 403: Respiratory Section
FICK'S LAW OF DIFFUSION STATES: "The rate of transfer of a gas through a sheet of tissue is proportional to the tissue area and the dirfference in gas partial pressure between the 2 sides and inversely proportional to the tissue thickness."
Fick's Law of Diffusion is the property that governs the transfer rate of gases through tissue.
The diffusion consant is proportional to the solubility divided by the square root of the molecular weight.
www.usc.edu /dept/biomed/bme403/Section_1/fick.html   (417 words)

  
 21533. How to qualify a metallic plating-substrate system regarding its diffusion properties? [France]
In the connector industry, it is this way the growth of intermetallic compounds is mitigated to reasonable low thickness by choosing the mating surfaces according to their diffusion constants and the required "mean" operating temperature during the timelife.
Diffusion considerations are intended to ensure that the material chosen from corrosion considerations to be on the surface will not be replaced by an other one.
Firstly, Ficks Law of diffusion is x^n = kT, where x is the diffusion distance, T is the temp and n is the growth law exponent and K is a constant.
www.finishing.com /215/33.shtml   (1273 words)

  
 Fick's law of diffusion: Facts and details from Encyclopedia Topic   (Site not responding. Last check: 2007-10-09)
Fick's laws of diffusion describe diffusion ((physics) the process of diffusing; the intermingling of molecules in gases and liquids as a result of random thermal agitation)
Fick's laws of diffusion were derived by Adolf Fick (Adolf eugen fick (1829-1901) was a german physiologist and inventor....)
Fick's First Law is used in steady state diffusion ((physics) the process of diffusing; the intermingling of molecules in gases and liquids as a result of random thermal agitation)
www.absoluteastronomy.com /ref/ficks_law_of_diffusion   (573 words)

  
 Diffusion Coefficient and Atomic Mechanisms
We are looking for an equation that links the diffusion current j of Ficks 1st law with the individual atomic jumps of a particle like an interstitial atom or a vacancy.
Ficks first law thus can be deduced in an unambiguous and physically sensible way for primitive cubic crystals in one dimension.
And g is a constant which is specific for the lattice under consideration, it is the so-called geometry factor of the lattice for diffusion.
www.tf.uni-kiel.de /matwis/amat/def_en/kap_3/basics/b3_1_3.html   (658 words)

  
 Fundamentals of Ventilation
Ficks Law of diffusion states that the amount of gas that moves across a sheet of tissue is proportional to the area of the sheet but inversely proportional to its thickness.
Diffusion of gas within the airways then takes over as the dominant mechanism of ventilation in the respiratory zone.
The rate of diffusion within the airways is so rapid, and the distances covered arson short, that differences in concentration within the alveoli are virtually abolished within a second.
www.ebme.co.uk /arts/vent1   (2644 words)

  
 Fick's law of diffusion Information Center - ficks law of diffusion
Fick's Second Law is used in non-steady state diffusion, i.e., when the concentration within the diffusion volume changes with respect to time.
Q is the activation energy for diffusion in dimensions of [energy / parts]
Carbon Dioxide in air has a diffusion coefficient of 0.16 cm^2/s, and in water, it's coefficient is 1.6 X 10^-5 cm^2/s [1].
www.scipeeps.com /Sci-Biochemistry_Topics_E_-_F/Fick's_law_of_diffusion.html   (418 words)

  
 Chap 14
Diffusion is a transport of atoms or molecules caused by their random thermal motion.
The law of mass balance is applied to both bloodflow and oxygen flux in Eq.
Although the diffusion area at rest is close to the size of half a tennis court, and the diffusion distance (L) is 0.5 - 1 micrometer, it is difficult to predict their variations between individuals.
forlag.fadl.dk /sample/paulev/book/chapter14/kap14.htm   (4649 words)

  
 Learn more about Diffusion in the online encyclopedia.   (Site not responding. Last check: 2007-10-09)
Learn more about Diffusion in the online encyclopedia.
Enter a phrase or search word in the box below.
Hint: Play with putting spaces before and after your words to see the different results you get.
www.onlineencyclopedia.org /d/di/diffusion.html   (738 words)

  
 HUCM Intro to Pharmacology: Pharmacodynamics
Passive diffusion is the direct movement of a solute through a biologic barrier from the phases of higher concentration to a phase of lower concentration.
The transport mechanism is by invagination of the cell membrane to form a vesicle and the engulfing of the invagination.
Y is a lipid-soluble drug which combines with carrier, C, at the outside surface of the membrane to form a complex, CY, which moves across the lipid membrane.
www.med.howard.edu /pharmacology/handouts/pharmacodynamics.htm   (3965 words)

  
 Chem / Physics Notes 7/7   (Site not responding. Last check: 2007-10-09)
rate of diffusion of a gas compared to another gas varies inversely with the sq root of the mw(reciprocal) of time with uptake - can plot out uptake of anesthesia gas for eg 1 large molecule diffuses slower than a small molecule, but the solubility of a molecule can alter this rule.
Consider solubility - CO2 diffuses 20 times faster than O2, because its more soluble than O2, even though its larger than O2 Daltons law - the total pressure exerted is = to the pressure of all the gasses in the mixture.
diffusion is affected and different per different gas (bec of the wt), think of the rate of flow of the same amt of molecules of different gasses and how gasses are delivered
www.hodsonhome.com /mna2001/chemphysics/chemphysic_notes7.7.htm   (1506 words)

  
 Oct 21 2005 journal club   (Site not responding. Last check: 2007-10-09)
Turbulent transport is an important and fairly ubiquitous process in nature, relaxing gradients and moving passive and active constituent quantities in systems ranging from geophysical (oceans, atmospheres and magnetospheres) to lab (chemical, biological, fusion plasmas etc) and all the way to astrophysical (stellar, galactic and larger).
We often model this turbulent transport using a parameterized diffusion equation (Ficks Law) and add ballistic flow terms to the equation to fix the inconsistencies between the observed behavior and diffusive behavior.
The end result is a general fractional diffusion equation whose derivation and implications will be discussed.
ffden-2.phys.uaf.edu /Oct_21_2005_journal_club.htm   (126 words)

  
 [No title]
Experiments are being conducted to determine the suitability of a cellophane membrane 0.029 thick for use in an artificial kidney device.
In an experiment at 37oC using NaCl as the diffusing solute, the membrane separates two components containing stirred aqueous solutions of NaCl, where c1=1.0X10-4 g.mol/cm3 and c2=5.0 X 10-7 g.mol/cm3.
The mass transfer coefficients on either side of the membrane have been estimated as equal and its value is 5.24 X 10-5 m/s.
www.annauniv.edu /academic/mqp5sem-ug/ib333.doc   (985 words)

  
 Untitled Document   (Site not responding. Last check: 2007-10-09)
The chloride diffusivity of Irish portland cement concrete is being investigated through laboratory and field trials.
The performance of pulverised fuel ash and ground-granulated blastfurnace slag concretes in comparison with portland cement concrete is also being examined.
These parameters will be used to test the validity of mathematical models of service life prediction, particularly those based on Ficks Second Law of Diffusion.
www.ucd.ie /civileng/berg/projects/cdrsc.htm   (92 words)

  
 Pysiology Class Notes 7/8, 13 & 15
diffusion works great over tiny distances but is inefficient over large areas, such as in multicellular animals.
Ficks law describes diffusion in terms of proportionality- and looks at proportionality of movement in one direction as well as movement in another direction.
Think of diffusion and conc gradient, and how the flow is between the capillary to the tissue and back to the cap again.
www.hodsonhome.com /mna2001/physiology/physiology1/phys1notes7.8.htm   (2523 words)

  
 Dissolved oxygen   (Site not responding. Last check: 2007-10-09)
A sediment oxygen flux model is developed whereby the sediment flux is related to the dynamic oxygen budget in the sediments.
The sediment dissolved oxygen flux is based on Ficks law of diffusion (e.g.
The diffusion coefficient is adjusted to include the effect of bioturbation, which can increase diffusion by up to 15 times the molecular value, i.e.
melchior.cwr.uwa.edu.au /Presentations/lake_management/images/caedym_science/section09.html   (1785 words)

  
 Walters Replies to Patterson. Origins Research 10:1. Walters, Tracy
Patterson's misdirection is also clearly evident in his second "fact." In context, my point here was merely that a definition of the Second Law can begin with any number of physical phenomena.
That mass doesn't diffuse against a concentration gradient is just a statement of Ficks' Law of diffusion.
Although there may be specific cases where the Law doesn't hold, because another phenomenon is operating simultaneously, Ficks' Law can be used as a basis for defining the Second Law.
www.arn.org /docs/orpages/or101/101walt.htm   (860 words)

  
 [No title]
A model function based on Fick's second law of diffusion is used to describe the concentration with respect to location and time.
In order to find the values of the diffusion coefficients they are encoded to data structures on which the mechanisms of evolution can be applied: mutation and selection.
It is shown how the convergence speed is influenced by the optimization parameters: the more individuals are involved in the evolution process, the fewer the generations it takes the algorithm to fit the parameters.
alife.ccp14.ac.uk /memetic/~moscato/memetic.bib   (7380 words)

  
 Legal Marijuana : Law Books and Data   (Site not responding. Last check: 2007-10-09)
Completely revised legal marijuana and expanded in content, it includes new topic areas such as HIPAA, delegation legal marijuana and supervision of unlicensed personnel, environmental safety issues, disaster situations, impacts of the nursing shortage, medication errors, communication, mandatory overtime, nurse-patient ratios, legal marijuana and the medicinal use of marijuana.
See live article   Boyle's law Boyle's Law is one of the gas laws, and relates the volume and pressure of an ideal gas held at a constant temperature.
The law, expressed in symbols, is: PV = k Where V is the volume of gas, P is its pressure, and...
www.compdatagovtedi.com /193-Legal-Marijuana.html   (784 words)

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