Systems and methods for dispensing fragrances are disclosed. The air separator blows the relatively light MSW recyclable materials up though a chamber and onto a first conveyer while the other relatively heavy MSW material drops down a chute onto a second conveyer. The tubes of each boiler form at least one water wall. The sensor control unit also includes two or more conductive contacts disposed on the housing and configured for coupling to two or more contact pads on the sensor. For example, the film structure can be used as an effective barrier layer in integrated circuit fabrication.