The pitch circle diameter (PCD) of a gear is a vital measurement when using gears. When you mesh two gears together, the teeth need to mesh to a precise distance, if too deep then the teeth will bind and wear, too shallow and you will get excessive back lash and risk damage to the teeth.
Burping gas that smell strongly of rotten eggs is actually indicative of the presence of sulfur in our stomach. This is the reason why this type of burps is commonly known as sulfur burps. The smell of sulfur burps or rotten egg burps usually comes from the presence of hydrogen sulfide.
Excessive burping. Burping is also referred to as eructation, ructus or belching. It may be described as the expulsion of air or gas from the stomach through the esophagus to the mouth. In some cultures, this is acceptable and is taken to mean that one is appreciating the good meal he or she has just had.