Final answer:
Porosity due to excessive moisture on a joint surface can be prevented by properly preparing the joint surface, ensuring it is clean and dry to avoid issues during solidification, similar to the role tight junctions play in biology.
Step-by-step explanation:
Porosity caused by excessive moisture on the joint surface can be prevented by properly preparing the joint surface before the joining process. This includes making sure the surface is clean and dry. The preparation avoids porosity issues by ensuring that no moisture is present which might create cavities in the joint during solidification. In welding, for example, it is vital to remove any contaminants that could prevent the proper fusion of materials. By increasing heat transfer and filling in gaps, a well-prepared surface leads to a stronger and more reliable joint. In biology, tight junctions serve a similar purpose by preventing undesired substances from permeating tissue. Both of these examples highlight the importance of proper surface preparation and the use of tight junctions to maintain integrity and function.