The name is absent



Chapter 3

echo at time t∈∙ The measurement is repeated after time spacing fR.

(--------

________________⅛_____________________________I

-----------------)

Repeat..

_____Time

ξ_________

90o

I code

180 o

g read

Echo
л

A A A

0                               '

------------------------------------------------∣-J----∣-W-------------------------r
V V

Figure 3.6 Sequence of MRI 1-D profile measurement

Magnetic gradient pulse is applied during echo signal collection. The total
signal at the time of the echo is [2]:

¾(0 = jp(z)exp[-i/Gz(t-tE)]dz                                 [3.31]

A Fourier transform of Sz(t) yields the spin density p(z).

Signal amplitude at position z is proportional to spin density ρ(z) and can be
expressed as the function of T∣, T2, fR and ⅛ pl:

A = AQ(l-e~tRlTl)e~tE,T2                                          [3.32]

3.4.2. Ti weighted 1-D MRI profile measurement

When the oil∕water concentration is varying as a function of z, the contrast in
the spin density is not large enough to give useful information of oil/ water
distribution. This is the case for water-in-diluted bitumen emulsions in which large
drops may accumulate at the bottom while small drops may stay at the top. To

54



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