Meshing a particle inside a cube with surrounded interphase

Hi,
Sorry about my english :">. I am trying to mesh a spherical particle with a surrounded interphase centered in a brick. I see a topic with something like that before, then I followed the ideas and I did it, it’s work well, here is a snapshot of this first model:

or http://s635.photobucket.com/user/thinhgt18/media/Brick_2_zps2bbbfe58.png.html

But, I don’t like very much the mesh in the interphase. Because I want some radial things in the interphase. So I did another way to mesh, here is the journal file:

reset
brick x 50
create sphere radius 16
subtract body 2 from body 1
create sphere radius 16 inner radius 10
webcut body all with plane xplane offset 0
webcut body all with plane yplane offset 0
webcut body all with plane zplane offset 0
undo group begin
imprint body all
merge body all
undo group end
volume 3 7 15 11 17 13 5 9 scheme Polyhedron
mesh volume 3 7 15 11 17 13 5 9
volume 14 18 16 6 10 8 12 4 size auto factor 5 propagate
volume 14 18 16 6 10 8 12 4 size auto factor 5 propagate
mesh volume 14 18 16 6 10 8 12 4

Here is a snapshot for this second one:

or http://s635.photobucket.com/user/thinhgt18/media/Brick_zps0a54d426.png.html

But, I have a problem. I can’t mesh the particle inside the interphase. I tried to partition it with a cylinder, but it isn’t work.
So I post this message to ask for some help.

Have a nice day!

Am I correct that the journal file leaves an empty space in the middle? I created a sphere with radius 10 to fill that inner core. Then I webcut all so the inner sphere would also be decomposed. Then set vol all scheme Poly.

reset
brick x 50
create sphere radius 16
subtract body 2 from body 1
create sphere radius 16 inner radius 10
create sphere radius 10
webcut body all with plane xplane offset 0
webcut body all with plane yplane offset 0
webcut body all with plane zplane offset 0
undo group begin
imprint body all
merge body all
undo group end
volume all scheme Polyhedron

volume all size auto factor 5 propagate
mesh volume all