Molecules with a diffusion constant D = 1.0 x 10-10 m?s-1 are released at a constant...
During the non-steady state diffusion of nitrogen in a semi-infinite bar of steel, it is found that it takes 5 hours to reach a concentration of 1.38 wt% nitrogen at a depth of 1.0 mm. How much time would it take to reach the same concentration of nitrogen at a depth of 2.0 mm assuming the same surface and initial concentrations. Co = 1.38 wt%, Given T = 800 °C, D = 2.22 x 10-10 m?s-1, Cor = Owt%, Cs...
It is necessary to dope a pure silicon wafer with boron to have a conductivity 1.0 x 10% ( 2-m) 1. at a distance 0.1 μm below the surface. The concentration of boron on the silicon surface is held constant at 1.0 x1025 m3. How long does the experiment have to run if the furnace is at 900 °C? The diffusion coefficient for B in Si at 1200 °C is 2.5 x10-12 cm2/s and the activation energy, Qd, is 3.87...
(b) A dru A drug particle has a diameter of 3 nm. The release of the drug is considered as a point source and the drug is assumed to undergo 1D diffusion. (i) Estimate the diffusion coefficient of the drug in water at room temperature. (ii) How long would it take for the drug to first reach a point 1 cm from where it was released [5]
a) What is the diffusion coefficient (DHCi) at 99 °C for a very dilute solution of hydrogen chloride, HC, in water? The ionic diffusion coefficients in water at 25°C are 9.31 X 105 cm2/s for H and 2.03 X 105 cm2/s for Cl. Start this problem by calculating the ionic |diffusion coefficients at 99 °C from those given at 25 °C assuming the viscosity of water at 25 °C and 99 °C is the same. Assume there is no current...
(1 point) Consider the diffusion of a dye in a narrow tube 40 cm long whose ends are connected to large dye-free chambers for all t> 0. Find an expression for the concentration c(x, if the initial concentration in the rod is given by the function 0 sx s 20, 40-x. 20
plastic 5. Consider the diffusion of water vapor through a polypropylene (PP) sheet 2 mm thick T pressures of H20 at the two faces are 1 kPa and 9 kPa, which are maintained constant. Th permeability coefficient of H2O through PP is 38 x 103 (cm STP)-cm/cm2-s-Pa. Assumin conditions of steady state, what is the diffusion flux, in [(em STP/em-s), at 298 K? Answer:ー-52,10ーフ (cm3 STP)/cm2-S 1.52 10 5. Consider the diffusion of water vapor through a polypropylene (PP) sheet...
3. Consider a growth factor (e.g. VEGF) that is released in the extravascular space such that its concentration Co in the extracellular space is constant and equal to 1 μM. The goal is to deliver the VEGF to the endothelium of a blood vessel passing through this space. The outer radius of the vessel (RO) is 200 μm and the inner radius Ri is 150 μm. The thickness of the endothelial layer is 1 μm. The diffusion coefficient of the...
Diffusion Mechanisms - Nonsteady State Diffusion - Copy Learning Goal: To learn how the diffusion rate changes in dynamic conditions where the diffusion profile changes with time, and how in some cases it can be modeled easily In steady stadision, the concentration Cis a function only of position (not of time). When usion is nonsteady Cis a function of position and time, Oix Nonsteady state diffusion in one direction can be modeled using Fick's Second Law -D where is the...
Problem 1: Chapter 6, Problem 12 IN 1.0 x 10% kg 1.5 X 1010 m 1.0 x 1010 m A spaceship of mass 1.0 x 10° kg is accelerated at a rate of 1.0 m/s? towards a binary star, which consists of two stars of equal mass m, as shown in the figure. Find the mass m of each star.
The decomposition of XY is second order in XYand has a rate constant of 7.12×10−3 M−1⋅s−1 at a certain temperature. What is the half-life for this reaction at an initial concentration of 0.100 M? How long will it take for the concentration of XY to decrease to 12.5% of its initial concentration when the initial concentration is 0.100 M? How long will it take for the concentration of XY to decrease to 12.5% of its initial concentration when the initial...