update heading sizes

uni/mmme/2044_design_manufacture_and_project/bearings.md

@@ -14,7 +14,7 @@ lecture_slides: [ ./lecture_slides/Lecture 7 - Bearings 1 – Plain Hydrodynamic
 <details>
 <summary>
 
-## Plain Journal Bearings
+### Plain Journal Bearings
 
 </summary>
 
@@ -24,7 +24,7 @@ lecture_slides: [ ./lecture_slides/Lecture 7 - Bearings 1 – Plain Hydrodynamic
 - the insert provides lower friction and less wear than if just rotating in the support
 - the bearing may be dry rubbing or lubricated
 
-### Lubrication
+#### Lubrication
 
 - hydrodynamic---a shaft continuously in oil. the load is carried by pressure generated in the oil
   as a result of the rotation
@@ -38,7 +38,7 @@ lecture_slides: [ ./lecture_slides/Lecture 7 - Bearings 1 – Plain Hydrodynamic
 <details>
 <summary>
 
-## Ball and Roller Bearings (Rolling Element Bearings)
+### Ball and Roller Bearings (Rolling Element Bearings)
 
 </summary>
 
@@ -54,7 +54,7 @@ lecture_slides: [ ./lecture_slides/Lecture 7 - Bearings 1 – Plain Hydrodynamic
 <details>
 <summary>
 
-## Plain Rubbing Bearings (Dry Sliding)
+### Plain Rubbing Bearings (Dry Sliding)
 
 </summary>
 
@@ -68,7 +68,7 @@ lecture_slides: [ ./lecture_slides/Lecture 7 - Bearings 1 – Plain Hydrodynamic
 <details>
 <summary>
 
-## Oil Lubricated Porous Bearings
+### Oil Lubricated Porous Bearings
 
 </summary>
 
@@ -82,7 +82,7 @@ lecture_slides: [ ./lecture_slides/Lecture 7 - Bearings 1 – Plain Hydrodynamic
 <details>
 <summary>
 
-# Hydrodynamic Bearings
+### Hydrodynamic Bearings
 
 </summary>
 
@@ -94,6 +94,8 @@ lecture_slides: [ ./lecture_slides/Lecture 7 - Bearings 1 – Plain Hydrodynamic
 
 ![](./images/vimscrot-2022-11-15T17:56:26,739425867+00:00.png)
 
+</details>
+
 
 
 # fun graphs that may be useful for bearing selection