A membrane is to be manufactured to the following specifications. At 700°C the leak rate ofhydrogen at steady state is not to exceed 103 mol cm2 hr' when the concentrations ofhydrogen are maintained at Chigh = 7.7 × 1019 atoms cm³ on one side of the membrane and Cloweffectively zero on the other side. Determine the minimum thickness, {, of iron foil that willmeet these requirements. The diffusion coefficient of atomic hydrogen in iron, DH, at 700°C is3.091x104 cm? s. Express your answer in units of cm.

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Answered: A membrane is to be manufactured to the…

Elements Of Electromagnetics

7th Edition

ISBN:9780190698614

Author:Sadiku, Matthew N. O.

Publisher:Sadiku, Matthew N. O.

ChapterMA: Math Assessment

Section: Chapter Questions

Problem 1.1MA

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Methane is diffusing at steady state through a 0.5mm diameter and 4mm long tube containing nitrogen gas at 101.32 kPa and 298K. Methane entering the tube is at 2.31x10 Pa and leaving the tube at 1.013x10 Pa. The diffusivity of nitrogen in methane gas is 0.140 x10m/s. Calculate flux of methane. Mention the unit of the flux. Paragraph BIEE
[Decarburization] An FCC iron-carbon alloy initially containing carbon with the concentration, C0, is exposed to anoxygen-rich and virtually carbon-free atmosphere. Under the given conditions, the carbon diffuses from the alloy andreacts at the surface with the oxygen in the atmosphere, meaning that the carbon concentration at the surface position is maintained essentially at 0 wt% C. The subproblems are independent.(1) Determine the diffusion coefficient at the temperature T given below. Use T = 1250 °C(2) When the value of D is given below, what position will the carbon concentration be Cx after a treatment for thetime, t? Use D = 1.93 × 10−10m2 /s; C0 = 0.35 wt%; Cx = 0.11 wt%; t = 12 hr
True or False? Justify your answer. A. In a rectangular drug delivery device that consists of a drug reservoir and a diffusion barrier made of a polymer gel, the steady state diffusion (mass transfer) rate through a barrier of thickness 1 cm was found to be 20 mg/day. If the barrier thickness were to be doubled keeping the reservoir drug concentration the same, the mass transfer rate would be 10 mg/day. B. In a spherical drug delivery device consisting of a core reservoir surrounded by a polymer gel barrier, the steady state diffusion (mass transfer) rate through a barrier of thickness 1 cm was found to be 20 mg/day. If the barrier thickness were to be doubled keeping the reservoir drug concentration the same, the mass transfer rate would be 10 mg/day.
Choose the correct Statement O a. Collision & diffusion is possible in all phases of a substance O b. The main forcefor Forced convection is the Buoyancy effect. O c. Radiation can take place only in objects having a temperature greater than 0 °C O d. For gases, Thermal conductivity (K) increases with increase in temperature
Define the two units used to express the concentration atmospheric polhutants: parts per million (ppm) and Cu = . Covert 0.l ppm to Cu.
Problem 1 0.1 moles of an ideal gas at pressure p= 1.000 bar is confined to a cylinder by a piston. The apparatus is thermostatted at T = 300 K. A weight of mass m is placed on the piston, and the gas expands until its pressure has dropped to 0.9600 bar, lifting the mass through a height of 0.500 m. (1) What is the largest value that the mass m can have in this process? (2) After the expansion is complete, we remove the mass m and replace it with a weight of larger mass m'. The piston now falls back through 0.500 m, compressing the gas, and returning the gas to its initial thermodynamic state. What is the smallest value that m' can have in this process? (3) Assuming that m has its maximum value, and m' its minimum value, compute the total thermodynamic work for this cyclical process. Is net work done by the system, or on the system, or is no work done? Draw a qualitative graph on a pV plot that illustrates what you have found. We will see later that your result is a consequence of the…
**JUST PART C PLEASE** The pressure in a pipeline that transports helium gas at a rate of 5 lbm/s is maintained at 14.7 psia by venting helium to the atmosphere through a 0.25-inch internal diameter vertical tube that extends10 ft into the air. Helium and atmospheric air are at 60F. The diffusion coefficient for a mixture of helium with air is 2.79 ft2/h at 77oF. Assume the mole fraction of helium in the atmosphere is negligible, and the mole fraction of air in the helium pipeline is negligible. Determine the following:(a) The mass flow rate of helium flowing to the atmosphere through the tube.(b) The mass flow rate of air that infiltrates into the pipeline.(c) The net mass flow rate in the vertical tube.
The diffusion coefficients for species A in metal B are given at two temperatures: D (m²/s) 7.81 x 10-17 7.70x 10-16 i (b) Determine the value of Do. (a) Determine the value of the activation energy Qd (in J/mol). i T (°C) 1030 i 1260 J/mol m²/s (Use scientific notation.) (c) What is the magnitude of D at 1180°C? m²/s (Use scientific notation.)
At approximately what temperature (in Kelvin) would a specimen of an alloy have to be carburized for 2.0 h to produce the same diffusion result as at 760°C for 13 h? Assume that values for Do and Qd are 1.3 × 10-4 m²/s and 135 kJ/mol, respectively. T= i K
(5) The characteristic equation of gasses (PV-mRT) holds good for (a) Monoatomic gases (b) ideal gases (c) mixture of gases (d) diatomic gas (e) Non in the mentioned. (6) The processes or systems that do not involve heat are called a) Isothermal processes (b) equilibrium processes (c) thermal processes (d) (e) steady processes (f) Non in the mentioned adiabatic processes (7) Which of the following is not a property of the system? a) Heat, mentioned (b) Temperature, (c) specific volume, (d) pressure, (e) Non in the (8) During throttling process (a) Internal energy does not change, (b) pressure does not change, (c) volume change is negligible, (d) entropy does not change, (e) enthalpy does not change, (f) Non in the mentioned. (9) (a) Triple point involves equilibrium of solid, liquid and vapor phases, (b) Critical point involves equilibrium of solid and vapor phases, (c) Critical point involves equilibrium of solid and liquid phases, (d) Critical point involves equilibrium of solid,…
You wish to carburize 0.2 wt% C steel ball bearings. The balls have a diameter of 2.5 mm. You anneal them at 930 °C in an atmosphere which fixes the surface carbon concentration at 1 wt% C. (a) How long will it take to raise the average C concentration to 0.6 wt% ? (b) What is the concentration at the centre of each ball at this time?
3. Mass Transfer from a Pipe Wall. Air at 52.6 °C and 1 atm abs pressure passes through a pipe with naphthalene lining. The pipe's diameter in 25 mm. The vapor pressure of naphthalene at 52.6 °C is 1.0 mm Hg. The diffusivity in air of naphthalene at 0 °C is 5.16x106 m?/s. For a 0.20 m section of a pipe that is lined with naphthalene, calculate the exiting concentration if the entering air carries 0.001 kgmol/m of naphthalene and has a velocity of 0.30 m/s. A.3-3 Physical Properties of Air at 101.325 kPa (1 Atm Abs), SI Units Ax 105 (Pa s, or (K) (kg/m) (kJ/kg K) kg/m s) (W{m K) N, (1/K) Bx 10 9Bp 1 (1/K -m) k (°C) - 17.8 255.4 1.379 2.79 x 10% 2.04 x 108 1.72 x 10 1.12 x 10 0.02925 0.702 2.95 0.775 x 10 0.03115 0.694 2.74 0.534 x 108 0.03323 0.692 2.54 0.386 x 10* 0.03531 0.689 2.38 0.289 x 108 0.03721 0.687 2.21 0.214 x 108 0.03894 0.686 2.09 0.168 x 10* 0.04084 0.684 1.98 0.130 x 10 0.04258 0.680 1.87 0.104 x 108 1.62 0.02250 0.720 3.92 0.02423 0.715 3.65 1.0048 273.2 1.293 1.0048…

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