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Flux & Flux Density

Flux comes from the Latin word fluxus which means flow. There are two common uses for the term flux. In the transport phenomena, flux is defined as the rate of flow of a property per unit area. Flux as a mathematical concept also represents the surface integral of a vector field. Both definitions of flux are based heavily on mathematics and differential calculus.

In the transport phenomena there are eight different types of transport fluxes. The eight include: momentum flux, heat flus, diffusion flux, volumetric flux, mass flux, radioactive flux, energy flus and particle flux. Each of these fluxes are vectors at each point in space and have a definite magnitude and direction. For incompressible flows, the divergence of the volume flux is zero.

The surface integral of flux is


F is the vector field

dA is the vector area of the surface A

The surface normal is directed usually by the right-hand rule. Once can consider the flux the more fundamental quantity and call the vector field the flux density. Often a vector field is frawn by curves following the flow. The magnitude of the vector field is then the line density. The flux through a surface is the number of lines. 

China State in Flux

I need help on writing a response discussing a state (China) that has been "in flux" between a democracy and another form of goverment over the past 20-25 years (an example might be Russia's struggle with establishing a democracy).

Magnetic circuit model: A second winding is added

The core illustrated in Fig. 13.51(a) is 1 cm thick. All legs are 1 cm wide, except for the right-hand side vertical leg, which is 0.5cm wide. You may neglect nonuniformities in the flux distribution caused by turning corners. a) Determine the magnetic circuit model of this device, and label the values of all reluctances in

Insulating material bombarded with electrons - charge density

In pdf format, please provide the following, the derivations of formulae. I will draw all the sketches myself: When a block of insulating material such as Lucite is bombarded with electrons, the electrons penetrate into the material and remain trapped inside. In one particular instance a 0.1 microampere beam bombarded an

Flux explanations

Can someone take a look at the below explanations and let me know if I need to change how it is worded? Please make any suggestions you deemed as necessary. Thanks. 1 - "Decrease In the accrued Accounts Payable (A/P) account is due to larger A/P accrual in December 2008 of $2.0M vs. A/P accrual in May 2009 of $1.8M; larger


Please note this: In my textbook theta is angle from Z-axis to the vector-r Phi is the angle from the x-axis to the vector projection on the x-y plane Compute the total flux...of the vector field...out through sphere

Electrostatics: Electric flux through a rectangular sheet.

A flat sheet is in the shape of a rectangle with sides of lengths 0.400 m and 0.600 m . The sheet is immersed in a uniform electric field of magnitude 74.5 N/C that is directed at 20 degrees from the plane of the sheet (see the attachment). Find the magnitude of the electric flux through the sheet.

Heat transfer Using Reynolds Analogy

A circuit board with a dense distribution of integrated circuits (ICs) and the dimensions of 120mm by 120mm on a side is cooled by a parallel flow of atmospheric air with a velocity of 2 m/s. From wind tunnel tests under the same flow conditions , the average frictional shear stress on the upper surface is determined to be

Electrostatics: Charge, flux and Field.

The electric field strength 4.10 cm from a very wide charged electrode is 4000 N/C. What is the charge (in nC) on a 2.00-cm- diameter circular segment of the electrode?

Electric Field Components

An electric field has the components Ex = -5, Ey = 6 and Ez = -6. A unit cube has its corners at (x,y,z)=(0,0,0), (1,0,0), (1,1,0), (0,1,0), (0,0,1), (1,0,1), (1,1,1), and (0,1,1). (All fields are measured in N/C and all distances are in m.) Calculate the electric flux through the cube at the side x=1. Calculate the electric flu

Flux Analysis

Obtain the most recent financial statement of any company that you would like to research. Please state the name of the company, its business activity along with key financial data (sales, operating profit, net income, assets, liabilities and equity of this company). 2. Obtain the same information for one of company's compe

Magnetic Circuits

Given the relationship B/H=u H=IN/l and L=N*change in magnetic flux/change in coil current show that the inductance of a coil is: L=N^2/S where S=l/uA

Vector Fields

1 Calculate the divergence and curl of the vector field F(x,y,z) = 2xi+3yj+4zk. 2 Find the potential of the function for the conservative vector field: F(x,y,z) = (y+z)i + (x+z)j + (x+y)k. 3 Use Green's theorem to calculate the work done when a particle is moved along the helix x = cos t, y = sin t, z

14 Modern Physics Questions

See attached file for full problem description. 1. A certain string on a piano is tuned to produce middle C (f = 261.63 Hz) by carefully adjusting the tension is the string. For a fixed wavelength, what is the frequency when this tension is doubled? a. 130.08 Hz b. 185.00 Hz c. 370.00 Hz d. 446.63 Hz e. 523.26 Hz 2

Transformer Magnetising Current

The primary winding of the transformer considered in question has 1000 turns. The iron core has a cross section of 70cm^2, and a mean path length of 150cm for the magnetic flux within it. The permeability of the iron may be assumed to be 0.0040 henrys per metre. (a) Calculate the maximum flux and flux density in the iron core

Megnetic circuits: MMF and reluctance.

The magnetic circuit shown in figure below is built up of solid iron cross section, 1x1cm2. Each air gap is 1 mm wide. For this type of air gap, the effective cross-section of the air may be taken as 1.2 x that of iron path to allow for fringing. Two different grades of iron are used. When a coil having 2000 turns is wound on pa

Transformer Wiring

Please help me draw a picture with a description of the solution with a step-by-step analysis using equations: 1) An enclosed transformer has four wire leads coming from it. How could you determine without taking the transformer apart: a) which wires are paired with which and b) what is the ratio of turns on the two coils? A

Electrostatics: Unequal Charge density on parallel plates

(See attached file for full problem description) --- 1. Consider two infinite parallel plane conducting plates, of finite thickness, with separation d. Suppose a charge density of sigma; is placed on one plate, while the other plate has -2sigma. A) Determine the resulting charge densities on each of the 4 surfaces B) De

Current in a Loop

If the current in the loop of the attachment were halved, the total flux threading the loop would: 1) Halve 2) Be reduced to 1/4 of the previous value 3) Decrease to 3/4 of its original value 4) Decrease by more than 1/2 but greater than 1/4 its previous value.

Electrostatic flux through a circular region

What is the electrostatic flux of a field of magnitude 6 N/C through a circular region with radius 9.2 meters, if the field makes an angle of 25 degrees with a perpendicular to the plane of the region?