Fungal nail infections can be caused by three different types of fungus, alone or in combination. 1  Dermatophytes are a type of fungus that can grow on the skin, hair, and nails. 2  They don't invade the deeper tissues of the body. 3  The most common dermatophyte, Trichophyton rubrum, causes most cases of athlete's foot.
Negative Airflow. Negative airflow is the opposite of postive airflow its having more exhaust fans then intake fans, this is good because its always taking new air into the case, but then you have more dust because the intake is mostly coming from gaps in the case and then causing trapped air.
A negative pressure (-) is below. The amount of air flowing through a duct is regulated by the amount of pressure difference and by the system resistance. The higher the pressure difference, the greater the air velocity and the greater the quantity of air that will flow from the duct. Friction is a resistance which slows down airflow. The flow of air creates friction as it rubs against the side of the duct, and the friction creates resistance to the airflow. Think of blowing through a piece of garden hose 6 inches long. You can feel a good stream of air coming out of the tube. Now try to blow through a hose 50 feet long.